What can you do if there are problems with the plants in your aquaponic filter?
Where do you go for information on how to both diagnose and treat any problems you may occur. The most commonly found problems are due to plant nutrient deficiencies with insect infestations following. We are lucky in that there is a growing literature on growing fish powered plants on a commercial scale. Although we are focused on the home aquarium with an aquaponics garden as the filter, these larger installations provide a great resource to help solve and identify problems with plant nutrient deficiencies. There is a very good article that outlines the various tell tale signs that are shown by plants when they are in difficulty or stress. In Feeding your Food: Plant Nutrient Deficiency and Toxicity in Aquaponics Systems the deficiencies found are in two separate classes:
The word ‘nutrient’ refers to the elements plants ‘eat’. Some of these include nitrogen, potassium, phosphorus, magnesium, iron and calcium.. To help figure out if your plant is deficient in something, we can split these nutrients into two groups: ‘mobile’ and ‘immobile’.
– Mobile Nutrients: Yep, these nutrients move around inside the plant. In fact, these nutrients move from older leaves to newer leaves to assist with growth. If the plant is deficient in a mobile nutrient, the symptoms will show up in the older leaves first, because the nutrient will move up to where the new leaves are growing and won’t be replaced in the old leaves.
– Immobile Nutrients: These nutrients can’t move once they have been used in plant growth. This means that when a plant isn’t getting its fill, the symptoms will show up in the newer leaves first, as the old leaves still have their immobile nutrients fixed there, whilst there isn’t sufficient new supply for the new leaves.
Solving Plant Nutrient Deficiencies
The post goes on with a good troubleshooting guide to identify the problem the plants are displaying and then what possible treatments may be effective in dealing with them. It is quite possible that you are going to have problems with the plants if the aquarium is not maintained very close to neutral (pH of 6.8 is the best) and this is often the first place where an improvement will make a large difference for the plants.
It is a good thing that most fish will at least tolerate this pH value for their water. The actual communities that can be kept are not impacted too greatly in most cases. Extremes in this area will show up as plant nutrient deficiencies. Be sure the water in your tank is close as possible to the 6.8 pH value as possible. After this has been determined then actual plant nutrient deficiencies could be evaluated.