Steve Millett, Technical Service and Sales Representative:
As a certified crop advisor, Steve has experience in greenhouse operations, plant nutrition, plant growth consultation and plant diagnostics. His crop experience includes vegetables, ornamentals, mushrooms, microgreens, grapes, turf grass and forestry. With a Ph.D. in plant pathology/nutrition and a background in botany, Steve relates well to both scientists and growers. He has worked extensively with hydroponic growers, edible and ornamental plant growers, urban farmers, traditional vegetable farmers, orchardists, and viticulturists. He has a passion for the local food movement and helping communities become food self-reliant.
Dr. Gene Giacomelli has a dream to grow veggies on the moon. Gene has dedicated his research at the Controlled Environment Agriculture Center (CEAC) at the University of Arizona in Tucson to designing a lunar greenhouse that will enable astronauts to grow food in outer space. As a student of the UofA’s Greenhouse Tomato workshop I was given the opportunity to visit Gene’s Lunar Greenhouse. Walking into the room and first seeing the Lunar Greenhouse gave me goosebumps. Being that close to something that important to the future of space exploration gave me an adrenaline rush of inspiration. Gene’s work and the work of others at NASA and around the US will enable us one day to live on another planet. Thanks to Gene we are one step closer to that dream.
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.
Dean Kopsell, University of Tennessee
Eating marigold petals
Dr. Dean Kopsell talks about why we should eat marigold petals and what his students found to be the best red to blue ratio for peak carotenoid concentrations.
Dean is a professor at the University of Tennessee and has studied an eclectic range of crops including Arabidopsis, basil, broccoli, cilantro, kale, lettuce, microgreens, onions, purslane, spinach, squash, turfgrass, and tomatoes.
1. Dean’s UT url:
2. Selected work of Dean Kopsell:
3. Dean’s Social Media:
Dean on Twitter: @UTPhytonut
2015 ASHS Undergrad. Educator Award winner Dr. David Kopsell pictured with his older, less talented brother. pic.twitter.com/6Wad96QAVs
Dr. Gioia Massa, “Veggie” Scientist at the Kennedy Space Station, NASA
“NASA’s Veggie and Space Kids”
Dr. Gioia Massa is a plant scientist in NASA’s Veggie program which aims to grow plants in the International Space Station (ISS). Gioia is a Future Farmers of America (FFA) alumni and has grown her early love for plants to a career that is now helping us explore space and preparing humans for space travel. Her professional talks are captivating, inspirational, mind-boggling and always end up giving me goosebumps. She talks with me briefly about NASA’s “Veggie” program on the ISS and how kids on earth are being inspired to reach for the stars.
Dr. Frits Went and the Pursuit of the McCree Curve
Dr. Bruce Bugbee of Utah State University was the opening speaker at the 2016 International Society for Horticulture Science Symposium on Light in Horticulture. Dr. Bugbee talks candidly with me about how understanding history can give us a keen insight into today’s botanical questions about light and the outlook of our future.
For more information on Dr. Bugbee’s program visit these sites:
Propagating in coco coir is a great way to establish plants. Now with the new Closed Bottom Organic Plug, CBOP, from Hort Americas you can reap the benefits of what you sow.
CBOPs are available in three sizes to fit the specifications of your production system. Whether it is nutrient film technique, raft, grow bag, or directly back into Riococo blocks/slabs, the new CBOP is easy to use and has all the benefits of using Riococo coir.
Currently, we have the 32mm (1.26 in) and 42 mm (1.65 in) size available. The 25 mm (0.98 in) size will be available in 2016.
pH & EC measurements 2:1 water extraction
To see more product information on the Hort Americas Closed Bottom Organic Plug, click here.
The most important thing when using Grodan stone wool is that you need to saturate the product fully before using it. When you don’t fully saturate it, some of the stone wool can stay dry and will be hard to get wet at a later stage (hydrophobic). A way to check if the product is fully saturated is to weigh the product and it should be above a certain weight. As an example a Grodan Delta DM6G Grow Block of 10 x 10 x 6.5 cm (4” x 4” x 2.5”) has a volume of 650 ml, so in theory if it is completely filled with water it should weigh 650 grams. However, there will always be air in the Grodan rock wool so we take a water content (WC) of about 85% after initial saturation, meaning the Grow Block should be approximately 550 grams or slightly greater.
I recommend using nutrient solution at 5.5 pH when saturating the product so that nutrients are immediately available for the plant. For the germination itself nutrients are not needed, so some people saturate the plugs with just water and then add the nutrient solution immediately following germination. However, fairly quickly after germination nutrients are needed for further development. So to sure it is easier to saturate the plugs with nutrient solution. Most growers use 1/2 rate nutrient solution for starting then full rate at transplant.
Below are characteristics of some of the most common types of Grodan used in hydroponic production.
Grodan AO cubes 25/40 10/10
AO cubes are recommended for lettuce, herbs, and other greens in a raft system as the tapered base makes it easier to fit into the raft faster.
AO 25/40 mm (0.98 x 1.58 in) L25 x W25 x H40 mm 200 (20 x 10) cubes per pad 6,000 cubes per case 30 pads per case
Top = 25 mm Bottom = 19 mm Height = 40 mm Hole = 10 x 10 mm Weight dry (1 cube) = 2 g Weight saturated (1 cube) = 18 g Also available: AO 36/40 = 1.5 in; 98 cubes/pad; 2,940 cubes/case AO 50/40 = 2 in; 50 cubes/pad; 1,500/case
Grodan AX cubes 25/40 10/10
AX cubes are recommended for lettuce, herbs, and other greens in a NFT system as the wider base gives the plug more stability in the gutter.
AX 25/40 mm (0.98 x 1.58 in) L25 x W25 x H40 mm 200 (20 x 10) cubes per pad 6,000 cubes per case 30 pads per case
Top = 19 mm Bottom = 25 mm Height = 40 mm Hole = 8 mm (1/4”) # per pad 200 (20 x 10) Weight dry = 2 g Weight saturated = 18 g
Grodan Kiem Plugs in French Trays
Kiem Plugs in French Trays # per tray = 240 (12 x 20) Height = 2.1 cm Dry weight = 1 g Kiem Plugs Height = 2.1 cm Weight dry = 1 g Weight saturated = 9 g
Grodan Block Delta DM4G
DM4G 7.5 x 7.5 x 6.4 cm (3 x 3 x 2.5 in) Weight dry = 25.3 g each Weight saturated = 273 g each Volume = 368.7 cubic centimeters 85% WC = 313.4 g
Grodan Block Delta DM6G
DM6G 10.2 x 10.2 x 6.4 cm (4 x 4 x 2 1/2 in) hole = 1.5/1.6 in (36/40 mm) Weight dry = 45.6 g each Weight saturated = 494 g each Volume = 655.5 cubic centimeters 85% WC = 557.2 g
Grodan Block Delta DM9G
DM9G 15 x 10 x 6.5 cm (6 x 4 x 2.5 in) two holes Weight dry = 67-73 g Weight saturated = 879 g Volume = 975 cubic centimeters WC 85% = 828.8 g
Grodan Grotop Expert Slab
Grotop Expert 100 x 20 x 7.5 cm (39.4 x 7.9 x 3 in) (99 x 19 x 7.8 cm) Weight dry = 753 g
Also available from Hort Americas:
Grodan Block Delta DM9G 27 x35 top right (144/case)
If your phosphorus fertilizer is sourced from the U.S. it is probably derived from Hillsborough, Polk, Manatee, and Hardee counties in Florida. Recently, I had the opportunity to tour Mosaic’s South Fort Meade Mine facility. The Mosaic Company’s South Fort Meade Mine has an annual production of 6.5 million tons per year running 24/7/365. It’s size is 28,000 total acres with 15,000 currently active acres with 3 drag lines.
Process Overview: Three Steps
1. Mining – Phosphate matrix is extracted from the ground. Clay and sand are removed. The refined phosphate rock is transported by rail for further processing.
2. Fertilizer production – Mosaic process nutrients in the phosphate rock into a water soluble form suitable for plant uptake
3. Distribution – Finished fertilizer is distributed both domestically and internationally by ship, barge, rail and truck directly to growers.
The massive production draglines are massive excavators (Fig. 1) that actually can move slowly across the mine dragging an oversized bucket. The Production Draglines are manned by just two employees. Each of the draglines weigh 6.9 million pounds and the bucket alone weighs 100,000 lbs (Fig. 2). The mining cut can be up to 320’ (Fig. 3). The overburden (sand & clay) is first removed to uncover the matrix of phosphate rock, sand and clay. The matrix is removed until it reaches hardrock (limestone or dense clay). If you are lucky enough you can discover prehistoric shark teeth or bones from creatures that once ruled the ocean where the mine is today.
Pit cars deliver water hydraulically with 300 psi and 16,000 gym to churn the matrix into a thick slurry that can be pumped back to the plant. At the plant, the washer removes oversized material between 1- 8 inches. Clay is scrubbed and rinsed away where it is moved to the clay reclamation centers. The washer feeds all undersized phosphate and sand smaller that 1mm to the Flotation Plant for separation. A biodegradable soap from pine trees is used to separate the phosphate from the sand. The sand is used to reclaim the mine. Since 1975 all mined land is reclaimed acre for acre (Fig. 4).
The phosphate rock is then loaded and shipped to fertilizer plants all over the US and then it eventually ends up in your hands where you use it grow healthy plants.
Special thanks to Mosaic company and the American Society for Horticulture Science for offering this unique tour.