One of the easiest deficiencies to spot on plants.
Potassium deficiency is characterized by a cupping or “puckering” of leaves and affects older leaves first. Leaf cupping is usually accompanied by a slight marginal chlorosis, with the leaf margins dying especially at the tip in severe cases. Leaf symptoms are accompanied by abnormal fruit development, cucumber fruit often developing a brown or spotted appearance and melons often developing abnormal flesh texture and off flavor.
In aquaponics, potassium is the number 1 most deficient nutrient there is. The issue is very easy and quite cheap to control to insure you have healthy plants in your system at all times. One of the first tell tell signs is that your plants will start to wilt during the heat of the day, and this does not mean high heat. We see leafy greens wilting and laying down on the media beds in only 75 F temperatures. Next you will see the older leaves become chlorotic, then necrotic, from the edges of the leaves and working back to the center of the leaves.
In some cases, the tomatoes when becoming ripe will display areas that remain green.
Correcting Your Potassium Deficiency
For PH from 7.0 and up you have two choices
- Seaweed Extract (power)
- Potassium Sulfate
For the lower range PH systems below 7.0
- Potassium Hydroxide
For all PH ranges.
- Potassium Chloride sprayed on the leaves of the plants only.