Plant nutrition is a key factor in growth and yield. But how can we know which nutrient is missing? Or which is the best fertilizer for our crop?
In learning about plant nutrition, we first need to know there are nutrients required in greater quantities than others. The nutrients that are essential for plant growth are called “macronutrients”. The rest of the nutrients also essential for plant growth but in lower quantities are called “micronutrients”.
It’s not that hard to do once you understand some fertilizer basics.
By Deidre Hughes
Mixing your own fertilizer solutions might seem like a daunting task at first. But once you understand some fertilizer basics you’ll realize it’s not that hard to do. One of the biggest benefits of mixing your own fertilizer solutions is the amount of money you’ll save. Another benefit of mixing your own solutions from dry fertilizers is that it requires less storage space than pre-mixed fertilizers which are often in liquid form.
How you grow and process fresh cut basil will impact the flavor and shelf life of the harvested product.
Basil is one of the most popular culinary herbs. Whether grown as a potted crop or for fresh cut sales, basil is an herb that’s in demand year-round. Growers looking to add edibles to their product mix should consider basil to be a must-have herb in their product offerings.
The 17 Essential Plant Elements include nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, chlorine, iron, manganese, zinc, copper, molybdenum, and nickel.
The non-mineral essential plant elements include hydrogen, oxygen, and carbon. These are either taken up as a gas or water.
There are 4 elements that are beneficial to promote plant growth but are not considered to be necessary for completion of the plant life cycle. They are silicon, sodium, cobalt, and selenium.
Figure 1 illustrates the essential and beneficial elements location on the periodic table. You can see that there are three clusters of elements within the periodic table.
These elements can be further divided into either macro- or micronutrients based on the relative concentrations typically found in plant tissues. The macronutrients include nitrogen, potassium, calcium, magnesium, phosphorus, and sulfur. The micronutrients are chloride, iron, boron, manganese, zinc, copper, molybdenum, and nickel.
The 17 essential plant elements can be remembered using a clever Mnemonic device that my botany professor Dr. Max Bell taught me in my undergraduate days at Truman State University. Here is the mnemonic device to remember the 17 essential plant nutrients of higher plants:
HOPKNSCa Fe is Mighty good and Clean. The owner is my Cu Zn Mo B the Nickel Miner.
The beneficial mineral elements can be remembered as a “Cozy Sinner” (Co Se Si Na).
Figure 1. Periodic table of the elements illustrating the essential and beneficial elements in higher plants.
In hydroponics, these mineral elements come from either the fertilizer salts you add to your source water or are already present in your source water. The macronutrients carbon, hydrogen, and oxygen come from either water or gases in the air.
Our Hort Americas Hydroponic fertilizer (9-7-37) was specifically designed to meet the unique needs of hydroponic plant production. Please contact us at to find our why Hort Americas Hydroponic Fertilizer is the perfect fertilizer for your hydroponic system.
Trials with organic and conventional fertilizers in hydroponic production systems are showing it’s possible to produce edible crops at much lower nutrient levels.
How much different is it growing edible crops organically than it is with conventional production inputs? Hort Americas special projects manager Tyler Baras is studying the differences in trying to grow organically versus using conventional production methods.
Baras has been doing organic production research in a 12,000-square-foot greenhouse in Dallas, Texas, using four deep water culture ponds and a nutrient film technique system. The ponds measure 4-foot by 8-foot and are 10 inches deep. Baras said the ponds are smaller than what would be found in many commercial greenhouse operations, but said the pond size is common in vertical farm setups. Baras has been trialing commercial organic fertilizers including Pre-Empt and an experimental organic fertilizer. The organic fertilizers are being compared with crops grown with Hort Americas 9-7-37 hydroponic fertilizer with calcium nitrate and magnesium sulfate. All of the production systems have also been incorporated with the commercial microbial inoculant TerraBella. Crops being grown in the production systems include Italian basil, green butterhead and red butterhead lettuce.
Rethinking optimum nutrient levels
Baras said the deep water culture production results he has gotten with Pre-Empt organic fertilizer have been comparable to the crops grown with the conventional Hort Americas hydroponic fertilizer.
“With Pre-Empt we have been able to match the growth rates of the conventional salt fertilizer,” Baras said. “As a result of the growth rates we have gotten with the organic fertilizer, we have started to question the nutrient recipes that have been recommended for hydroponic edible crop production. Many of the traditional recipes for hydroponic production have a target level of 200 parts per million nitrogen. But we are seeing the same growth rates in the organic fertilizer ponds with 10 ppm nitrogen as the 200 ppm nitrogen conventional fertilizer pond.”
Baras said the electrical conductivity level in the organic fertilizer ponds has been as a low as 0.5 compared to 2.5 in the conventional fertilizer pond and the crops are coming out nearly identical in terms of production time and plant weight.
One difference between the organic- and conventional-grown crops is the time in propagation.
“The crops are finishing at the same time from transplant to harvest time, but we are keeping the plants an extra week in the seedling stage for the organic fertilizer,” Baras said. “We are running the seedlings for two weeks with the conventional fertilizer and about three weeks with the organic fertilizers.
“The organic plugs are started a week earlier, but they are transplanted on the same day as the conventional plugs. We want the roots coming out of the side of the plugs before we transplant them into the ponds. The seedlings are fairly similar in size when they are transplanted into the ponds.”
Once the organic and conventional plugs are placed into the ponds, they both spend the same amount of time there until the crops finish.
“The plants are coming out of the ponds with nearly identical weights,” Baras said. “Overall the seed to harvest time is faster with the conventional fertilizer, but that it is because we are able to transplant the plugs into the pond faster because the roots are coming out of the plugs sooner.”
Baras said the plants grown with the organic fertilizers have also shown they can be grown with lower levels of other nutrients. For example, with the conventional fertilizer the nutrient solution may contain 200 ppm potassium and the level is only 12 ppm with the organic fertilizers.
“Aquaponic growers have seen similar situations,” he said. “Some aquaponic growers may be running an EC of 0.7 with a relatively low nutrient level, but they are still seeing good growth.
We are seeing that as well with the organic fertilizers. There are low nutrient levels in the solution, but the crops are coming out the same and the leaf tissue analysis is nearly the same as well.
“For our trials the macronutrient uptake for the plants, even when they are grown in a low fertilizer concentration like 0.5 EC, they are still able to pull what they need out of the solution. Leaf sample analyses of butterhead lettuce and Italian basil grown in 0.5 EC organic fertilizer vs. 2.5 EC conventional fertilizer, most of the macronutrient levels in the leaves are very similar. It appears the plants are doing a good job of regulating the nutrient uptake to get what they need.”
Aging fertilizer solutions
Baras said letting the organic fertilizer solutions age in the ponds may have an impact on the availability of nutrients for some crops. The aging of the fertilizer solutions also has an impact on increasing the microbial population.
“We have definitely seen some differences in plant growth,” he said. “Our first crops of butterhead lettuce and basil did very well with Pre-Empt organic fertilizer. However, one of the other organic fertilizers we trialed grew a quality first crop of lettuce, but not the best looking basil. As we continued the trial with our second and third crops, the basil grown with the other organic fertilizer started doing much better. It appears the organic solutions in the ponds may need to age until the nutrients reach adequate levels.
“This is what we were seeing in a 9-month old Pre-Empt pond vs. a 2-month old Pre-Empt pond. A lot of nutrients have accumulated in the 9-month pond and are approaching the recommended nutrient levels that would be found in a conventional fertilizer system. Organic fertilizers like Pre-Empt don’t have a lot of magnesium in them. However, when the fertilizer is run in a pond system for 9 months the magnesium level rises and approaches what would be considered a conventional fertilizer target level for magnesium.”
Aging of the fertilizer solution also has had an impact on the root growth of the crops.
“When we compare how the roots look visually in the 9-month solution vs. the 2-month solution, the roots in the 9-month solution look much healthier,”Baras said. “The roots are very white, are longer and look really healthy and well-developed. There are also more roots on plants in the 9-month system.
“The root color is also significantly different. In the 2-month solution the roots look healthy, but there is some browning. They don’t have that crisp white look.”
Rethinking optimum pH levels
Baras said he has been able to produce healthy crops in a pH range from as low as 4 up to 6.5.
“For hydroponic leafy greens the recommended pH ranges from 5.5 to 6.5,” he said. “We have basil and butterhead lettuce growing very well in organic systems at a pH of 4. On the other side of the pH range, I’ve heard of aquaponic growers growing these crops at a pH up to 7 without any problems. Based on our trial results some of the conventional recommendations for hydroponics for both pH and nutrient levels might need to be revisited.
“One of the biggest issues I see with hydroponic growers is overcompensating. For instance, they feel that they need to be constantly watching the pH. They may set up monitoring and dosing systems to ensure the pH doesn’t go below 6 or 5.5. They are investing in extra equipment because they think they need to keep the pH precisely in this range. It may be a case that the plants will do well outside this range.”
Impact on crop timing
Baras said one factor that could affect the optimum pH and nutrient range is the light level.
“If a grower is providing supplemental light, then the optimum pH and nutrient range may be different,” he said. “With the trials we are conducting we aren’t that far off from what most hydroponic growers are targeting for growth rates. Thirty-five days is a target number for a lot of lettuce growers. We have done 35-day crops. We want to be able to grow an organic crop in the same amount of time as a crop grown with conventional fertilizers.”
For more: Hort Americas, (469) 532-2383; firstname.lastname@example.org; https://hortamericas.com.
David Kuack is a freelance writer in Fort Worth, Texas; email@example.com.
Tour of Hort Americas research and demonstration greenhouse in Dallas will show growers different hydroponic production systems for various vegetable crops.
Growers of hydroponic vegetables or those considering starting growing vegetables hydroponically should plan on attending the AmericanHort Production Technology Conference. Scheduled for Oct. 9-11 in Dallas, the conference begins with a Technology in Action Tour on Oct. 9 which will visit three local production operations: Hort Americas research and demonstration greenhouse, Seville Farms and Southwest Nursery.
All things hydroponic
Hort Americas, a horticulture and agriculture wholesale supply company, has retrofitted a 12,000-square-foot floriculture greenhousefor the hydroponic production of vegetable crops. Tyler Baras, who is the special projects manager at Hort Americas, is overseeing the trialing of five different production systems along with the testing of potential products for the company’s online catalog. The production systems include: nutrient film technique (NFT), deep water culture floating raft, a vertical hydroponic tower system, a flood-and-drain vertical rack system and a new capillary mat manufactured in Europe. The greenhouseis being used to grow a wide variety of lettuces, leafy greens, herbs and microgreens.
The NFT system uses a new channel design. Baras said the narrower channels allow for the aging of crops without having to physically move plants from nursery channels to finishing channels.
Hort America’s main floating raft deep water system is an in-house custom design that measures 32-feet by 28-feet.
“We have tried using a Venturi system to incorporate oxygen, but for the last two months we have been doing trials with compressed liquid oxygen,” Baras said. “We have been doing trials to see how plants respond to increased levels of dissolved oxygen. This deep water system hasn’t been flushed in over a year.
“We have been managing the nutrient solution with water tests and individual salts. Instead of using a standard N-P-K fertilizer like we have been using in the other production systems, we have really focused on water tests and making nutrient adjustments based on those tests. We have been trying to keep the nutrients within a target range and trying to run the system for as long as possible without having to flush any of the nutrient system. We are testing for all of the essential nutrients. We are also looking at sodium chloride levels and seeing how those accumulate. Also, we are tracking what essential nutrients accumulate over time and how we can adjust the fertilizer being added to accommodate the natural accumulation in the system.”
Baras is also studying how the water source can contribute to the nutrient level.
“We are considering how source water may be a limitation to applying this no-flush technique,” he said. “Our source water is municipal water, but it has a high sulfur content of about 44 parts per million. So we are looking at cutting out all sulfur inputs. We are learning the challenges of trying to manage a no flush system.”
In addition to the main deep water system, Baras said tour attendees will also see several smaller deep water culture systems.
“In these smaller deep water culture systems we will be showing the use of three different organic fertilizers where we are comparing the growth between them,” he said. “We will also be showing a smaller scale deep water culture system receiving aeration compared to one with no aeration.”
Vertical production systems
Another hydroponic system that Baras is working with is a vertical tower commonly used by smaller growers.
“We have a lot of customers who use this system so we decided to install one in the greenhouse so we could look at some of the issues that they are dealing with,” he said. “We also were looking to answer some of the questions that our customers had about using the system. An example is can this system be used to grow organically? We’ve done both organic and conventional trials with this system.
“We’ve also been looking at what crops perform best in this vertical system. We’ve done a lot of variety trials as well as with the other systems we’ve installed.”
Hort Americas is also trialing a vertical Growrack from Growtainer.
“This is a flood-and-drain vertical rack system,” Baras said. “The rack has three levels, but it could be expanded. The rack has a 2-foot by 5-foot footprint. We have equipped it with GE LED lights. This would be the type of system used in a vertical farm setup.”
Baras said the Growrack system, which is set up in the greenhouse, has done well in warm conditions because its water reservoir is below the rack.
“The reservoir is usually stored underneath the racks so it is in shade,” he said. “The water isn’t always in the trays so it doesn’t collect the heat from the trays. It works well in warm climates.”
Although Baras has grown full size crops in the Growrack, it is being used now primarily for seedling propagation.
“The focus of the system is how it has enabled us to cut back on the amount of space that is needed for propagation,” he said. “We can easily grow enough seedlings in this system for a 10,000-square foot greenhouse.
“The system is also being used by a Central Market store in Dallas to finish crops for its Growtainer farm. We helped consult on the management of the system and showed store officials how it could grow crops from start to finish in the same Growracks. The store is growing fully mature butterhead lettuce and basil in the system. This system can definitely work in indoor vertical farms.”
Baras said he has grown both organically and conventionally with the Growrack system.
In addition to trialing LED lights vs. natural light for greenhouse seedling propagation and crop staging, Baras said he is also looking at using LEDs supplemental light throughout the production of butterhead lettuce in the floating raft system.
“We are looking at how LED light affects leaf texture and plant morphology of butterhead lettuce,” he said. We are trying supplemental lighting during the summer. We are pulling shade so the light isn’t very intense. It appears that intense light can lead to tip burn that damages the plants leading to a poor quality crop. So we pull shade cloth and then run a prototype high-output LED grow light provided by GE for almost 20 hours. We deliver a low intensity of light over a longer period so we can provide the plants the light they need without stressing them. We are trying to improve the quality by adding LED light in order to produce more compact growth that is associated with LEDs.
“Under greenhouse shade cloth the lettuce leaves look fragile. We are trying to grow the lettuce to hit a certain weight. If the plants are grown under shade they look fairly large and floppy and the head doesn’t have the right density at its core. By using the LEDs we can produce the more traditional morphology where the plants have a dense core. The leaves aren’t floppy and the plants look more like traditional butterhead should look.”
Matching plants and production systems
Baras said he is trialing a wide range of crops in all of the production systems he is using.
“Primarily we are focused on lettuce and basil, but we are trialing a lot of varieties,” he said. “We definitely see some systems are capable of growing some varieties that other systems are not. We want to be able to recommend what varieties grow best in what systems. We are preparing a book based on our research that will include an entire section on strategies for how to use these production systems. We will provide example situations in the book discussing location, climate, market, what crops are being requested by that market and how to use that information to determine what production system is most appropriate.
“We are looking at primarily butterhead, romaine and oakleaf lettuce and 20 different basil varieties. We are also doing trials with arugula, spinach, cilantro, kale, chard, Asian greens and microgreens. We are doing an extensive study of herb varieties. There are also some unusual crops like stevia, wasabi arugula, celeriac and sorrel. We are determining all of these plants growth habits in the different production systems. This information will be in the book along with the details and nuances of growing each crop.”
Based on the trial results, Baras said the book will provide details on each plant variety and its performance in each system.
“The book will provide information on the growth a grower should expect in different environments based on the amount of light and temperature,” he said. “The book will offer projected production numbers a grower should be able to reach. These will be realistic targets for each of the production systems we have studied.”
It is important to conduct water and nutrient solution analyses on a regular basis to ensure hydroponic tomatoes are receiving the proper level of nutrients.
Making sure that hydroponically-grown tomatoes receive the proper nutrient levels requires testing water and nutrient solutions. Growers also need to confirm that irrigation equipment is delivering the correct amount of fertilizer. Nutrient levels should be monitored and adjusted according to the crop developmental stage, the season, light levels and tomato type.
“In applying fertilizer to a plant grown either in soil or in a soilless medium, the goal is to match the nutrient uptake of the crop as closely as possible to the amount provided as fertilizer” (Mary Peet, USDA, Division of Plant Systems-Production, 2005). There are many reasons to do so, but a very important reason is to prevent fertilizer runoff which is actually money runoff.” For growers with open irrigation system this will hurt the most. In a closed irrigation system, excess fertilizer is recovered and recycled after water treatment.
Water sample analysis
It’s very important to regularly conduct irrigation water and nutrient solution (water + fertilizers) analyses. Irrigation water quality from a well, dam or municipal system should be determined before implementing any type of fertilization plan. Important levels growers should know include: water electrical conductivity (EC), water pH, sodium (Na), chloride (Cl) if using a municipal water source, calcium (Ca), magnesium (Mg) and sulfates (SO4). The preference is for low levels of all these elements. Water EC less than 0.5 millisiemens/centimeter (mS/cm) is a good level. If the water pH is high, a pretreatment can be done with sulfuric acid, phosphoric acid or citric acid. Optimum and safe pH levels are between 5 and 6.
Nutrient solution sampling should be conducted on a weekly or biweekly basis. Nutrient solution sampling should be taken from two sources:
1. Feed is the nutrient solution the irrigation system is pumping to the plants sampled at the dripper.
2. Drain is the leachate coming from the substrate. This is critical to a fertilization strategy.
The information obtained from the nutrient solution analysis helps to:
1. Verify the irrigation equipment is dosing the correct amount of fertilizer.
2. Verify the EC and pH of the nutrient solution are satisfactory levels.
3. Determine the amount of fertilizer by element being absorbed by the plants.
4. Determine the amount of fertilizer that needs to be added/subtracted from the nutrient solution.
It can be determined if the amount of irrigation is appropriate by looking at the drain EC. If the EC is too high, there may not be enough water being applied to the plants. If the EC is too low (lower than the feed EC) plants may be receiving too much water.
5. Verify if the amount of irrigation is appropriate by looking at the drain EC. If the EC is too high, there may not be enough water being applied to the plants. If the EC is too low (lower than the feed EC), plants may be receiving too much water.
There are many laboratories that perform this type of water and nutrient solution analysis. It is important to choose a lab where the staff has experience in hydroponics.
Two recommended laboratories are Groen Agro Control in the Netherlands and Perry Laboratory in Watsonville, Calif.
Recommended nutrient levels
In the photo of the Netafim crop management technology fertilizer dosing unit, the blue line on the left is the irrigation water (well water or municipal water with no fertilizer). This water is pumped to the mixing chamber where fertilizers are injected and the water becomes the nutrient solution (pink line on the right). The nutrient solution flows through EC and pH sensors to make sure that the target EC and pH are maintained.
Table 1 shows the nutrient levels by element or molecule recommended for tomato nutrient solutions measured at the drain. Elemental levels at the lower or higher margins are not necessarily bad. Maintaining the proper nutrient level is crop dependent.
Table 1 reflects the desired values obtained by a drain sample analysis. By constantly analyzing the nutrient solution, the target levels can be matched that best suits the crop.
Some tomato varieties are more susceptible to blossom end rot (BER) http://ucanr.edu/sites/placernevadasmallfarms/files/86509.pdf) than others. Check irrigation strategy and nitrate levels since high nitrates could be the cause of BER.
Keep daily irrigation measurements in a logbook (EC, pH and drain percentage). This is a daily task that should be performed early in the morning before the irrigation cycles start. See handheld EC/pH meters https://hortamericas.com/product-category/growing-supplies/meters/
Compare the manual EC/pH readings with the irrigation unit readings, they should match.
Keep K:Ca ratio close.
Calibrate pH and EC meters once a week.
Calibrate pH sensors on the irrigation unit at least once a month.
Keep the irrigation system clean and flush it periodically.
Clean fertilizer tanks every month to avoid fertilizer sedimentation.
Keep the pH of the micronutrient stock tank low (pH 4).
For more: Hort Americas, (469) 532-2383; https://hortamericas.com.
Here are some of the fertilizers Hort Americas offers:
Bell peppers grown in greenhouse hydroponic systems follow similar environmental requirements as tomatoes and eggplants. It is a common production practice to leave all the leaves on the pepper plants. This creates very tall walls of foliage that slightly affect the plants’ nutritional requirements.
Pepper growth follows generally two different phases during greenhouse production. After the seedlings are transplanted, the first six weeks of production is geared toward developing a strong vegetative base. After fruit set, the nutrient recipe is changed slightly to keep the plants in balance. For peppers only potassium is significantly increased after fruit set occurs.
Table 1. Nutrient solution for hydroponic pepper cultivation.
270-300 ppm (200 ppm*)
200 ppm (300 ppm*)
Concentrations in parts per million (ppm) at the dripper. Micronutrients are in shaded boxes. (*) See below for explanation on blossom end rot.
Like all nutrient recipes the numbers in Table 1 are a starting point that will need to be adjusted depending on the local environment (temperature, humidity, solar radiation and water quality) and the different salt accumulations that occur in normal conditions depending on the absorption by any given strain of pepper. Note that the ammonium (NH4) levels for young and mature plants are very low compared to nitrates. Ammonium is not necessary depending on the substrate included for pH buffering.
Note also that chloride and sodium have upper ranges. These two are considered contaminants even if they have nutritional value for the plants. They are generally present in the water and their requirements are very low similar to micronutrients.
Preventing blossom end rot
Bell peppers’ most common physiological problem is blossom end rot, which is generally due to a water stress preventing the internal transport of calcium. It is common to increase the concentration of calcium ions in the solution together with chloride, phosphate and boron while reducing potassium to promote the absorption of calcium during potential blossom end rot periods, particularly during hot summers (* in Table 1).
The most common chemicals for mixing nutrient solution are the following:
Ca(NO3)2 (Calcium nitrate)
KNO3 (Potassium nitrate)
KH2PO4 (Monopotassium phosphate)
MgSO4*7 H2O (Magnesium sulfate)
H3BO3 (Boric acid)
MnCl2*4 H2O (Manganous chloride)
CuCl2*2 H2O (Cupric chloride)
K2SO4 (Potassium sulfate)
MoO3 (Molybdenum trioxide)
ZnSO4*7 H2O (Zinc sulfate)
Fe 330 – Sequestrene (chelated iron)
Commonly in hydroponic production, chemicals are mixed in concentrated solutions to be diluted at the time of irrigation. The drawback of this fertilization method is that some of the chemicals present will precipitate out and be removed from the nutrient solution and need to be kept separate in at least two reservoirs. As a common rule, calcium needs to be separated from phosphates and sulfates to prevent precipitation.
Growers have affordable options for ensuring plants receive sufficient oxygen in hydroponic production systems to maximize growth and to reduce the chances of disease.
Oxygen is critical in the development and growth of edible crops grown in hydroponic systems such as nutrient film technique (NFT) and deep water raft culture. Tyler Baras, special projects manager at Hort Americas, is studying methods of adding oxygen to both conventional and organic hydroponic production systems in the company’s 12,000-square-foot research and demonstration greenhouse in Dallas, Texas.
“One of the big differences is how growers add oxygen,” Baras said. “A lot of times in conventional hydroponics, growers use air pumps and air stones to add oxygen. In organic systems these tend to be hot spots for biofilm development. We have removed all air pumps and air stones from the organic systems we are trialing.
In the conventional production systems Baras is studying he has installed water pumps with a Venturi attachment to add oxygen to the nutrient solution reservoir.
“The pumps aren’t injecting air into the irrigation lines, but simply into the reservoir to circulate the water and to create a circular flow within the fertilizer reservoir,” he said. “As the pumps operate they draw in air through a ¼-inch emitter. There is the benefit of moving around the solution and the air being drawn in increases the level of dissolved oxygen.”
A method that organic growers use to increase oxygen levels is cascading the water when it returns to the reservoir. As water returns it is allowed to fall and break the surface of the reservoir so that the water can pull in oxygen.
“This can also be done in vertical farms where the water will fall down large return pipes to the reservoir,” Baras said. “This can happen in multiple stages where the water will drop several times. This is an effective method for increasing dissolved oxygen.
“For NFT, it appears more oxygen can be delivered to plant roots when the flow rate is increased per channel. As the flow rate increases, more oxygen is delivered to the roots so water isn’t sitting in the channel as long. This allows freshly oxygenated water to be delivered quickly to the roots. In conventional hydroponic NFT systems the flow rate is about ½ liter per minute. In our hydroponic NFT system I have been aiming for about 1-2 liters per minute.”
Adequate oxygen levels
Baras said oxygen is necessary for plant roots to perform metabolic processes.
“Most of the water uptake in plants is passive,” he said. “But there is a stage where the plants use energy to actively pull up water through the roots. This requires oxygen. If there isn’t any oxygen in the root zone no water will make it up through the roots to the top of the plant. Low oxygen in the root zone can appear as wilting at the top of the plants. This can seem counterintuitive in a hydroponic system because the roots are sitting in water, but the tops of the plants look like their wilting if there isn’t any oxygen in that water.”
Baras said the need for oxygen in an organic hydroponic system is even more important because of the presence of living microbes in the fertilizer solution reservoir.
“These microbes also require oxygen,” he said. “The oxygen demand is often higher in organic systems than conventional systems because not only do the plant roots need oxygen, but the microbes need oxygen as well. In an organic hydroponic system one of the best ways of keeping biofilm in check is to keep the beneficial microbes happy.”
Baras said most of the oxygen measurements he has been taking in his research have been showing very similar oxygen levels for both conventional and organic production systems when the crops are performing well.
“I have been aiming for a level of 7-12 parts per million (ppm) dissolved oxygen, but generally the readings fall between 7-9 ppm,” he said. “I’m using a ProODO meter from YSI that is a very sensitive piece of equipment that accurately measures dissolved oxygen.”
Although most hydroponic growers are concerned with maintaining adequate oxygen levels, Baras said if too much oxygen is added to the solution it can cause root stunting.
“I haven’t reached that threshold yet in my trials,” he said. “It’s crop dependent on what that level is. When there is too much oxygen the roots have less motivation to grow larger because they are getting everything they need with a smaller surface area. That can then translate to the plants producing less biomass resulting in less leaf tissue. So at some point too much oxygen can actually cause less growth. For crops like tomatoes, peppers and cucumbers the whole plant would be stunted.
“The only way growers could reach excessive oxygen levels that damage the plants are when liquid oxygen or possibly ozone is used. Using air pumps or air stones to add oxygen, the levels won’t be high enough to stunt plant growth. To reach higher oxygen levels of 15-16 ppm, a grower would have to use other methods like liquid oxygen and ozone. It’s very difficult to reach high oxygen levels above 10 ppm unless an alternative method is used beyond air pumps, Venturis and cascades. I haven’t seen any growers go much higher than 8-9 ppm using the conventional methods.”
Baras said growers using a deep water raft system could try increasing turbulence in the pond to increase oxygen level. However, too much turbulence can sometimes cause damage to the roots.
“The roots in the turbulent areas are the ones that often times grow poorly,” he said. “The plants that are near the irrigation outlets where the currents are stronger, they have the poorest root growth. Sometimes growers will use air pumps in their ponds and those plants directly above where the air stones are located grow poorly.”
For more: Hort Americas, (469) 532-2383; https://hortamericas.com.
David Kuack is a freelance technical writer in Fort Worth, Texas; firstname.lastname@example.org.
When it comes to changing from conventional to organic hydroponic production methods, there are three main areas that growers find most challenging.
Tyler Baras, special projects manager at Hort Americas in Bedford, Texas, said growers are increasingly inquiring about organic hydroponic production. Baras is running hydroponic production trials comparing organic and conventional production methods in a 12,000-square-foot research and demonstration greenhouse in Dallas.
“We’re doing the research because of market demand,” he said. “A lot of growers are getting feedback from their customers that they would prefer to have produce that is certified organic. Produce suppliers and brokers hear from the grocery stores and then they bring those requests to the growers.
“We don’t necessarily believe that produce grown with organic production methods is superior. We believe in conventional production methods as well. What we are trying to do is provide as many options to our customers as possible.”
Baras said that organic production is a whole system that includes substrates, fertilizers and pest management. But most of the questions coming from growers about organic production are related to fertilizers.
Inoculants and tank culturing
Baras said an advantage of traditional fertilizers is all of the research that has been conducted on them has enabled growers to target exact nutrient profiles for specific crops.
“Research has enabled traditional fertilizers to come down to fairly exact levels,” he said. “Growers are able to figure out exactly how many parts per million of each nutrient they want to put into nutrient solutions. The chemistry allows them to be that exact.
“Organic fertilizers are a little trickier because there isn’t the precision targeting each nutrient. Generally there are inputs that are going to have several nutrients in them. Growers don’t have the ability to adjust individual nutrients as easily.”
Another issue with many commercial organic fertilizers is they are animal-derived. These organic fertilizers include manures, bone meal, blood meal and feather meal.
“These animal-based organic fertilizers don’t mix well with water,” Baras said. “If growers are using recirculating hydroponic systems, these animal-based fertilizers tend to start going rancid and smell in a few days. These fertilizers can also form a sludge that can clog irrigation lines and emitters.”
Baras has focused his research trials on Pre-Empt, a plant-derived organic fertilizer which has blackstrap molasses as its major component. He has been comparing organic vs. traditional fertilizers in several hydroponic production systems, including flood-and-drain grow racks, two different nutrient film technique (NFT) systems, deep water culture floating rafts and a ZipGrow Tower system.
“We have successfully grown butterhead lettuce and basil in all of these systems using organic inputs,” he said. “We have several other crops that we are running through these systems in smaller trials, including spinach, cilantro, arugula, strawberries and other lettuce and herb varieties. Most of research is still focused on butterhead lettuce and basil.
“We currently don’t have any trials going with microgreens, but some of our first trials were with microgreens under LED lights using organic substrates and organic fertilizers. We definitely proved that is a viable production system.”
Baras said he knows of growers using Pre-Empt organic fertilizer who haven’t flushed their nutrient solution tanks for five months.
“The key is the slow development of the fertilizer tank,” he said. “Some growers have immediately added the organic fertilizer to their reservoir at full strength and they quickly notice that their tank starts to foam at the top and starts to smell similar to what happens with animal-based organic fertilizers. We’ve found if an initial charge, about half the target rate, is added first, along with a microbial inoculant at the same time, these issues can be avoided. We are using Terra Bella as the microbial inoculant because it has an extensive profile of different microbes.”
Baras said the half rate of fertilizer and microbial inoculant are run through the system for about two weeks.
“Once the microbial population becomes established, the nutrient solution in the tank can be brought up to full strength without any foaming or odors,” he said.
Nutrient solution pH management
Baras said one of the major issues with the organic nutrient solution during the first two weeks is pH swings.
“The pH of the nutrient solution on the first day the organic fertilizer is added to the tank is in a good range around 6-6.5,” he said. “Within a couple days of adding the fertilizer, the nutrient solution pH shoots up to around 8.0. There are a lot of plants that do not like a high pH. Iron-inefficient crops like basil have a hard time taking up iron at a high pH. There will be a lot of chlorosis at the top of the plants. This happens within a couple days of the pH going above 7.
“During the second week the pH drops to between 4 to 5. The plants continue to grow, there are a lot of nutrients in the solution, but the quality is very different. During the third week the pH stabilizes. As the microbial population stabilizes, the pH stabilizes around 5.5-6.5, which is ideal for leafy greens.”
Baras said growers have taken two routes to stabilize the nutrient solution pH.
“There are growers who will let the solution go for this two-week swing and let the solution stabilize similar to what we have been doing,” he said. “Other growers are trying to control the pH with inputs. When the pH goes up they will add citric acid. When the pH starts to drop they will add sodium bicarbonate.
“The inputs to adjust the pH are very limited. The main downfall with citric acid is that it is anti-microbial. So although a grower is able to lower the pH, it’s not good for the microbial population. Another option is vinegar, but most commercial growers are using citric acid for controlling pH for organic production.”
Baras said the options for raising the pH are also limited.
“Growers would like to use potassium bicarbonate, but potassium bicarbonate is not allowed for pH management under the organic rules,” he said. “Potassium bicarbonate can be used to control powdery mildew, but it can’t be used to control pH in the nutrient solution tank. What growers are left with is sodium bicarbonate or baking soda. The pH can be raised, but over time sodium accumulates. Once a certain threshold of sodium is reached then problems start to occur including nutrient disorders.”
Baras said another issue with using citric acid and sodium bicarbonate for pH management is the longevity of the nutrient tank solution is shortened.
“It could be a couple months, but at some point the sodium levels are so high that either the whole solution or part of the solution is going to have to be dumped,” he said. “The tank is going to have to be flushed. The amount of citric acid and sodium bicarbonate added can be done in small increments, but it is the accumulation that causes problems.”
Baras said once the nutrient solution stabilizes, the swings in pH won’t be as drastic when additional water and fertilizer are added to the tank.
Another option for controlling pH includes adding more water or fertilizer.
“Depending on the water source, adding water to the tank can sometimes raise the pH,” Baras said. “Also, the Pre-Empt fertilizer is somewhat acidic and that could be used to lower the pH simply by adding more fertilizer.”
EC targets and nutrient analysis
Baras said growers who switch to organic production systems should continue to measure the electrical conductivity (EC) of the nutrient solution to determine soluble salts levels.
“A lot of the nutrients in organic fertilizers won’t register on EC readings because of the forms they are in,” he said. “They aren’t yet broken down into simple salts. If growers are basing their feedings solely on EC readings, the EC of the nutrient solution will probably read much lower even when sufficient nutrients are being provided to the crop.
“The specific makeup of the nutrient profile, how many parts per million of each nutrient, for organic and conventional fertilizers are not the same. I don’t target the same nutrient profile for an organic nutrient solution that I do with conventional nutrient solutions.”
Baras said plants are fairly flexible on many of the nutrients, which can be maintained within a fairly wide range.
“With organics, sometimes the calcium level may only be 100 parts per million where with conventional fertilizers the target calcium level for most leafy greens is around 200 ppm,” he said. “But even at 100 ppm calcium with an organic fertilizer, we are not seeing the issues that we would expect from having a low calcium level.”
Baras said for fruiting crops like tomatoes, calcium can be an issue with organic production.
“Calcium sulfate is an amendment that can be used to correct calcium deficiency,” he said. “Another nutrient that can be low with plant-based organic fertilizers is magnesium. What we have found is nutrients like calcium and magnesium that are usually lacking in the organic fertilizer we are using, they are generally found in the source water of most growers.
“In our research greenhouse the source water contains 30 ppm magnesium and 30 ppm calcium. Those can make a fairly significant contribution to the nutrient solution, especially with calcium that isn’t taken up as quickly as other nutrients. Over time the calcium level accumulates in the fertilizer tank. As the organic nutrient solution is used over several months, the calcium level rises and nearly reaches the conventional target of 200 ppm calcium. Like calcium, magnesium generally rises over time with source water contributions.”
Measuring changing EC levels
Baras said that he uses an EC meter to get an estimate of the soluble salts level in the organic nutrient solution.
“For lettuce the EC of the nutrient solution in the greenhouse for conventional production is usually run at 2-2.3,” he said. “For organic lettuce production I typically run an EC between 1.2-1.6. I make sure that the crop has the nutrients close to the target range by sending water samples to a testing lab to get an exact analysis. But even that has some issues with organic production.
“I’ve found that the amount of time a nutrient solution sample sits after it is sent out can affect the nutrient analysis from the lab. Since nutrient solution microbes are constantly active, changes can occur within the sample. Initially a sample sent to a lab may have 100 ppm nitrogen. But a few days later the same sample may indicate there is 150 ppm nitrogen.”
Baras has sent the same samples to multiple labs and he has received analyses with significant variations, especially with nitrogen. He suggests growers stick with one lab.
“If there is a lab that is relatively close to a grower’s operation, this can help ensure that results are returned relatively quickly,” he said. “The best practice is for growers to create their own archive of the nutrient analyses so that they can compare test results to previous notes. Lab test results are likely mimicking what is happening in the nutrient solution tank. The microbes’ activities are also affected by temperature the solution is stored at as well. The readings could come out higher or lower.
“There are different factors that can affect the EC including the temperature and the crop stage when a water sample is taken. Crop age, whether plants are young or mature, whether there is a well-developed root system along with the crop itself, impact the interaction with the nutrient solution. These can affect the form the nutrients are in and how that would read out on a nutrient analysis.”
Baras said how often an EC analysis should be done depends on how large the reservoir is and how often water is added to the reservoir.
“A small reservoir that is frequently amended with water should be tested fairly often,” he said. “Nutrients can quickly accumulate in a small reservoir. Growers with a small reservoir might be testing every week. With a large reservoir used for deep water culture that may contain 8,000 gallons of water, it is not as urgent to test as frequently.”
For more: Hort Americas, (469) 532-2383; https://hortamericas.com.
David Kuack is a freelance technical writer in Fort Worth, Texas; email@example.com.
We have been receiving a lot of questions about Pre-Empt. He are some responses to the common questions:
When is Pre-Empt appropriate?
It is best suited for recirculating hydroponic production of leafy greens. It can be used as a direct substitute for conventional fertilizers in NFT, DWC/Floating Raft, and Flood & Drain. When used properly, it won’t clog 1/4″ emitters which is very rare for an organic fertilizer.
When is Pre-Empt not appropriate?
The cost may be prohibitive for drain-to-waste systems. We do not have any experience with the product being used in aeroponic or aquaponic systems.
Can Pre-Empt be used for tomatoes?
-Growth may be overly vegetative and not as reproductive as standard commercial tomato formulas
-Blossom end rot will likely be an issue on larger varieties like beefsteaks
-Works well with grape and cherry tomatoes but still may have overly vegetative growth
-Calcium may be supplemented with an organic solution grade gypsum
What amendments would you suggest to use with Pre-Empt?
-Organic solution grade gypsum and silica may be used to reduce tip burn or blossom end rot
-Inoculants like TerraBella can help reduce biofilms and improve nutrient availability
How do I inoculate a tank with beneficial microbes?
Fill a 5 gallon bucket with water and add 1 oz molasses. Let water sit for 1 day to remove chlorine (unless using RO or distilled water). Add 2 oz. of TerraBella and let sit for 1 day before adding to reservoir. This is enough to inoculated 300 gallons of nutrient solution.
How often should I change the reservoir?
This is going to vary a lot depending on growing environment, system, water source, and fertilizer rate. In general, using a water source with a very low EC and keeping the fertilizer rate low will help extend the life of the reservoir. Some growers flush their system once every 4-5 months and some growers flush every two weeks. The cost to build a reservoir with Pre-Empt may be up to 100x more expensive than conventional fertilizers so it is very important to reduce the frequency of flushes.
What EC should I maintain?
This will depend on source water EC and crop. The target EC is generally going to be lower than the EC used with conventional fertilizers. Generally leafy greens are grown at an EC ranging from .8 up to 1.6. It is best to start low to avoid the development of biofilms in the system
What pH should I maintain? And how?
I’ve seen growers completely ignore pH while using Pre-Empt. The pH may fluctuate from 4.8 up to 7.5 without noticeable effect on the crop. I’ve also seen growers maintain pH levels with citric acid and sodium bicarbonate.
How consistent is Pre-Empt from batch to batch?
There is variability in the product and it is possible that a batch may perform differently than previous batches. This variability is generally minimal enough that growers do not need to adjust practices.
Early results from fertilizer trials in Hort Americas’ research greenhouse show knowing the levels of nutrients in fertilizer solutions can go a long way in avoiding problems with deficiencies and toxicities.
Hort Americas has retrofitted a 12,000-square-foot greenhouse in Dallas, Texas, for the purpose of studying edible crop production in a variety of hydroponic production systems. The greenhouse is also being used to demonstrate products offered in the company’s online catalog.
Tyler Baras, who is the company’s special projects manager, is overseeing the trialing of leafy greens and herbs in five different production systems.
“We’ve got a deep water culture or raft system using Hort Americas’ fertilizer blend with calcium nitrate and magnesium sulfate,” Baras said. “We are using that same nutrient mix in a nutrient film technique (NFT) system and a capillary mat system.
“I’m using Terra Genesis organic fertilizer in a vertical grow tower. I’m also using the same organic fertilizer for all of the seedling propagation in a flood-and-drain vertical rack.”
Baras said the fertilizer recipe he is using in the deep water culture and NFT systems is based on general recommendations from Cornell University and the University of Arizona for leafy greens crop production.
Differences in nutrient levels
The deep water culture system has been running for three months. The water reservoir for the system is 8,000 gallons.
“Even if water evaporates, since it is such a large body of water, the electrical conductivity (EC) doesn’t really move much,” Baras said. “The EC has been very stable during the three months it has been operating. The reading has barely moved.”
The first trial with the NFT system, which has a reservoir of about 140 gallons, lasted for three months.
“Every week I added an additional 40 gallons of water on average to the NFT reservoir,” Baras said. “The water is evaporating and the salts are accumulating a lot faster in the NFT reservoir than in the deep water culture system. Because the NFT system has a smaller water reservoir, the quicker evaporation rate and the water replacement in the reservoir, has caused the EC to shift a lot more.”
Baras said even with the changes in nutrient levels all of the plants have been performing well.
“I haven’t seen any nutrient deficiencies or toxicities even as the fertilizer recipe has shifted over time. We have been trialing a wide range of crops, including butterhead and romaine lettuces, kale, spring mixes and basil. I’m trialing a lot of crops to figure out when these crops start to be impacted by possibly too much salt accumulation. I haven’t seen anything yet that is alarming.
“One of the things that I have seen over the years working with fertilizers is how wide the acceptable range is for plants to grow well. Between the NFT and deep water culture, the NFT is using half the nitrogen and the plants are performing very similarly. There are recommendations for EC, but none of these fertilizer levels are set. I have some systems that have 20 parts per million phosphorus and some that have 50 ppm and the plants look the same. Most general recommendations say 40-50 ppm. I’ll have some solutions that have 3 ppm iron and others that have 6 ppm iron. It is interesting to see how wide the range is for a lot of these nutrients and the crops are performing the same.”
Baras said he has seen a slowing of plant growth in the NFT system.
“I’m not seeing any deficiencies or toxicities, but the crops have slowed down about a week over the deep water culture,” he said. “Depending on the crop, it’s taking a week longer to reach either the plants’ salable weight or height.
“The slowing in growth could be related to the nutrients. This could be useful information for growers. If they are checking the EC, which may have been 2.3 when a crop was started, if there is a slowing of growth, growers may want to have a water test done. The test could show that the amount of nutrients might be changing.”
Identifying what makes up the EC
During the three months that Baras had been running the NFT system he never flushed the system.
“All that I’ve done with the NFT system is add water and additional fertilizer to maintain a targeted EC,” he said. “One of the goals of the trials is to see what ions are accumulating in the system and to see how long I can run the system before it has to be flushed. When I started the target EC was 2.2-2.3. I still achieved the target EC at three months, but the composition of what was actually in the water changed.
“Originally the NFT fertilizer solution contained about 185 parts per million nitrogen. At the end of the trial the EC was the same but there was only 108 ppm nitrogen in the solution. The calcium concentration was originally 250 ppm and ended at 338 ppm. Sulphur was originally at 80 ppm and rose to 250 ppm. Nutrients have accumulated as the water evaporated. Solely going by the EC meter reading doesn’t tell the full story of what is in that water. The EC of the fertilizer solution that I started with is the same as the EC for the fertilizer solution three months later. The difference is the ions that are making up that ending EC.”
Herb production with organic fertilizer
Baras is growing a variety of cut herbs in vertical grow towers. The plants are fertilized with Terra Genesis, a molasses-based organic fertilizer. He said Hort Americas has been hearing from tower growers who are interested in trying to grow organically.
“What we are seeing is the organic fertilizer solution can change a lot over time,” he said. “The fertilizer tank solution matures as time goes on. With the organic fertilizer, the nutrients tend to balance out as the solution is run longer.
“Our city water contains calcium and some magnesium. These elements are actually the nutrients that the organic fertilizer is slightly low in. So as I run the system longer, through the addition of city water, I actually start to see an accumulation of both calcium and magnesium, which actually helps balance out the total fertilizer recipe. The balance of the nutrients has improved over time.
The pH was fairly unstable as it seemed to be going through several biological waves. It was moving rapidly between high and low. As I run the tank solution longer the total alkalinity has increased, which has stabilized it. The biological activity has also started to stabilize. The pH has stabilized in the upper 5 range. For the plants grown organically I have seen deficiencies pop up. The deficiencies were reduced as the fertilizer tank solution ran longer. The deficiencies appear to have balanced out.”
Baras said one noticeable difference between the NFT, deep water and vertical grow towers is how much slower the plants grow in the towers.
“I don’t know what to contribute the slower growth to yet,” he said. “It could be trying to determine the best fertilizer rate for the fertilizer. It could be the crop selection, because most of the crops in the towers are different from what I’m growing in the NFT and deep water culture.
“I’m going to start a deep water culture and NFT trial using organic fertilizer. I’ll have three different organic production systems running simultaneously so I will be able to compare the plant growth in each system. I’ll also be able to compare the growth of the same crops grown with organic or conventional fertilizers.”
Controlling biofilm, disease pathogens
Baras said one of the issues that can arise with using organic fertilizer is the development of biofilm in the irrigation lines that can cause emitters to clog.
“I am incorporating a product called TerraBella, which contains beneficial microbes,” he said. “These microbes help mobilize certain nutrients, like phosphorus, which can promote the formation of biofilms. This biofilm buildup is usually more of a problem with high water temperatures.
“About every six weeks I add a booster application of the beneficial microbes depending on the production system. The deep water culture system has a larger reservoir so I am not replacing evaporated water as often. For the other productions systems, like the NFT and grow towers, where I am replacing the water, I am incorporating the beneficials more often. For these systems, the fresh city water that is added dilutes the fertilizer solution. Also, there is chlorine in the city water that possibly could negatively impact some of the beneficial microbes.
Proudly brought to the commercial hydroponic and organic grower by Hort Americas and specifically developed for recirculating nutrient film technique (NFT), the Pre-Empt Hydroponic Nutrient is packed with the essential micro- and macro-nutrients, amino acids and vitamins plants hunger for!
Pre-Empt goes through a five stage fermentation process which is above and beyond other products by incorporating molasses with other natural plant extracts. This process packs Pre-Empt with essential macro-nutrients, micro-nutrients, amino acids like humic and fulvic acid, as well as an array of vitamins which build a full spectrum of nutrients that plants desire.
Excellent for lettuces, basil, leafy greens and culinary herbs
We suggest pairing with Terra Bella to naturally promote the uptake of nitrogen and other essential nutrients for plant health. The combination of aerobic and anaerobic microbes works throughout the root zone to increase crop yield and resistance to disease and pests.
For further resources including a quick video and Organic Fertilizer Programs, click here!
Pre-Empt can be used in conjunction with a solution grade organic gypsum (calcium sulfate) and magnesium sulfate.
Hort Americas is an innovative leader in North America’s controlled environment agriculture industry (CEA) and strives to continually innovate in agriculture via premium technical support, professional salesmanship, unmatched customer service and outstanding products to our customers in the United States, Canada, Mexico, and the Caribbean.
If you missed the e-GRO webinar “Managing Nutrient Solutions for Hydroponic Leafy Greens and Herbs” on Jan. 22, 2016, which was sponsored by Hort Americas, you can still view the webinar on YouTube.
Hydroponic greens and herbs are produced in systems with recirculating nutrient solutions. In order to maintain productive and quality crops, it is important to know how to properly maintain the nutrient solutions. Dr. Chris Currey at Iowa State University and Dr. Neil Mattson at Cornell University discuss strategies for managing pH and EC, formulating nutrient solutions and identifying common nutrient disorders.
Part 1: Common production systems, pH and EC management
Presented by Dr. Chris Currey, Iowa State University
Part 2: Nutrient solution recipes, common nutrient disorders
Testing your irrigation water quality is important and
should be done regularly. Frequency of water
samples is dependent on several factors. Growers should test their irrigation
water at least twice a year if producing crops year round. I know one grower that tests their water
weekly! At Hort Americas we are becoming
inundated with fertilizer requests and nutritional recommendations. The first question we’ll ask is “Do you have
results from a recent irrigation water quality test?” If the answer is yes,
great, please forward a copy of the results to us. If the answer is no, please have your irrigation
water quality tested. Next question,
“How do you sample your irrigation water?” Collecting water samples correctly
is important to ensure the results are accurate.
If you are not testing your irrigation water, why
not!?! That is one of the first things
you should do before a single seed is sown. Why? Well, if you don’t measure it,
you can’t manage it. On one hand, you
could be undervaluing your irrigation water by adding unnecessary soluble nutrients.
On the other hand, your irrigation water may be unsuitable for crop production
and/or require additional treatment before use. What do I mean? The irrigation water chemistry made need to
be treated to remove or correct nutritional issues. Or, your irrigation water
may have unwanted sediments that must first be filtered. Entire books are written on irrigation, so we
cannot cover everything in one edition of an e-newsletter. For now, let’s first focus on collecting the irrigation
water sample. As you recall, last month
I shared some videos on growing winter salad greens created by Dr. Brian Krug
from the University of New Hampshire. Once
again, Dr. Krug has composed both a valuable how-to article and a video to help
you correctly collect an irrigation water sample.
Have the right tools e.g. hose or spigot,
bucket, collection bottle, paper towels, submission form, envelope etc.
Flush the water line/hose for at least 3 to 5
Fill collection bucket
Use a clean collection bottle/container (at
least 8 ounces)
Submerge and fill the collection bottle and cap
under water (no head space)
Complete a submission form (if provided by
Dry and label the collection bottle accordingly
Deliver the envelope to the testing lab
Wait for results
Send Hort Americas a copy of your results J
For more information on irrigation water quality you may
want to read the following extension publications. Many state extension agencies have produced
similar articles. These are simply two examples of such articles. Check with your local extension specialist as
they may have more information relevant to your geographic location.
You may also want to
visit the Water Education Alliance for Horticulture. The Water Education Alliance for Horticulture is a team
of researchers and industry experts led by the University of Florida. Their mission is to “help growers conserve
irrigation water and manage water quality issues.”
Written by Dr. Johann Buck, Technical Service Manger at Hort Americas
Posted by Maria Luitjohan
Visit our corporate website at https://hortamericas.com
Its finally up and live! Kimitec.com is the perfect place to go to learn about the latest trials on this organic and non-organic line of fertilizers. From Amifort to Tundamix, the Kimitec Group (along with the support of American Clay Works in North America) continue to focus increased yield, plant health and vigor. Please follow this link to learn more about Kimitec Trials in hydroponics, commercial greenhouses and general agriculture.
Visit Hort Americas for additional technical information and to buy your Kimitec today.
Visit our corporate website at https://hortamericas.com