Micro Nutrients for Hydroponic Systems

By: Charlene Rennick

Micro nutrients are present in the soil in very traces amounts.  If a plant shows signs of ill-growth, they may need to be added to the hydroponic growing media. Because micro nutrients are not as high profile as macro nutrients are to hydroponic gardening, they are not usually included as part of the nutrient package.

Why would a Hydroponic Garden Require Micro Nutrients?

Sometimes, climatic abnormalities such as a sudden and intense heat wave can cause the plant to transpire too quickly.  When this happens, vegetation can become calcium deficient.  At other times, the pH level is the cause of improper nutrient concentrations. A pH level that is too high alkaline will reduce the probability that iron, manganese, boron, copper, zinc and phosphorus will be absorbed by the plant. A pH that is too low acidic will decrease the opportunities for potassium, sulphur, calcium, magnesium and phosphorous to be used.

Trouble-shooting micro nutrients for Hydroponic Systems

Let’s pinpoint some problem areas so you will know how to solve micro nutrient related growth problems:

Calcium is necessary for good cell wall strength. If the plant is calcium deficient, the leaves, flowers, or budding shoots might fall off the plant. Tomatoes may have brown and rotting spots on the bottom.

Sulphur aids in osmosis, protein production, seed formation and fruit development.  A lack of sulphur can result in yellow leaves that have a purple colour on the base.

Iron helps in the manufacture of chlorophyll, to respirate the sugar and to extract energy for growth.  Not enough iron is a common deficiency and will cause yellowing; it can be seen in the veins of leaves, and in new growth.  Often, new leaves will fall before they complete their growth.

Magnesium is used during the production of chlorophyll and plant enzymes.  When the plant does not have the right amount of magnesium, the area between the veins of the older leaves turns yellow, and will curl. The newer leaves stay green longer because the plant uses the chlorophyll from the old leaves, in the new growth.

Boron works with calcium to strengthen cell walls.  Without boron, the stems can become brittle and split.

Manganese is vital for plant growth and oxygen production. A deficit in the manganese level will cause yellowing of the area between the veins and failure to bloom.

Zinc is used during the process of respiration, the manufacture of chlorophyll and the metabolising of nitrogen.  If the zinc level is low, the leaves will be abnormally small with crinkling on the edges.

Molybdenum stabilizes the nitrogen levels.  If there is not enough molybdenum, the leaves will be yellow and tiny.

Copper energizes the process of photosynthesis and respiration.  Plants with a deficit of copper have yellow-coloured spots on paler than is normal, leaves.

Cobalt is one of the B-12 components necessary to all living forms.  The exact effect of cobalt in its excess or deficit is not known, but alfalfa and some legumes show trace amounts of cobalt in their nitrogen stabilizing organisms.

If you are having plant growth issues in your hydroponic system, bring a small sample of your nutrient solution and a spare leaf with you to a Hydroponics supply store.  The staff there should be able to help you.


  1. Rob says

    What is a good hydroponic micro nutrient supplement generally and specifically for a manganese deficiency? I am using an ebb and flow system if that matters.

Leave a Reply

Your email address will not be published. Required fields are marked *