Iron in Hydroponic Systems

Have you ever noticed the different presentations of iron when selecting ingredients to make nutrient recipes?

Iron can be presented in different ways. This element can easily precipitate in tanks or reservoirs when mixed with other elements. The best way to avoid precipitation is by adding Iron through chelates. This is why when looking to add Iron to your nutrient reservoir you should look for Iron chelate options.

However, there are multiple types of Iron chelated in the market. How can we know which could be the best option for our system? Iron chelated can be presented in different forms with different levels of stability. The stability of different Iron chelates in the system depends on the pH level of the solution. Iron chelated is used in soil and hydroponic systems. Also can be applied directly to the leaves by foliar applications. Based on this we can find mainly three types of Iron in the market: EDTA Iron chelates, DTPA Iron chelates, and EDDHA Iron chelates.

EDTA Iron chelates

  • Is the least stable type of Iron chelate showing stability between a pH of 3-6.
  • Is commonly used for foliar applications
  • Not recommended for use in tanks or reservoirs

DTPA Iron chelate

  • The most common form used in hydroponic systems
  • The stability of DTPA Iron chelate meets the requirements for most horticultural crops, showing stability between a pH of 3-6.5
  • There are different options for DTPA Iron chelate in the market. Is recommended to choose options with less sodium content (e.g DTPA 6%)

EDDHA Iron chelate

  • Shows stability between a pH of 3-10. The reason why is commonly used in alkaline soils.
  • Recommended for nutrient solutions with a pH of around 6.5 or more
  • There are different options for EDDHA Iron chelate. It is important to select the product with the highest ortho-ortho level. 
  • In ortho-ortho iron, the chelating agent “binds” iron in a more stable way, since it does not allow water to polarize and thus destabilize the particle.

A successful nutrient recipe will require us to understand the nature and chemistry of all ingredients. In Hort Americas, you can find the products and educational resources required to create successful recipes and keep your crop growing healthy.