Nutrient deficiencies in hydroponic systems
Nutrient deficiencies are especially important in growing plants hydroponically as the plants are completely dependent on the nutrients we supply in the water. Ethan Walter from www.brightagrotech.com has a nice video explaining in detail how to spot each type of deficiency and what to do in case of emergency.
If you like reading instead of watching the video, here is the summary:
In hydroponics we mainly talk about macro-nutrients and micro-nutrients. They can be mobile or immobile (meaning the plant can move the deficient nutrient where is needed or not) and this is important when you check for signs.
Besides knowing what are the signs of deficiencies and how do they look on a plant, the most important thing is to spot the signs early. If you spot the signs late, the plant might be too damaged to easily identify the initial problem so it’s harder to know what went wrong. Secondly, each plant has different nutrient level needs, so if lettuce does well in a nutrient solution, tomatoes might not feel so well. So it’s good to know the general demands of each plant you are growing hydroponically.
The macro-nutrients are: nitrogen, phosphorus and potassium.
Nitrogen is a mobile nutrient, so you first start to notice its deficiency in older leafs. Chlorosis is the main symptom of nitrogen deficiency – the leafs will become less green, pale or white, beginning from the tip of the leaf on the older leafs as the plant will try to move the nitrogen to the newer leafs.
Phosphorus deficiency is especially easy to spot as the leafs will turn darker or become purple (note that there are plants that are supposed to be red)
Potassium deficiency looks a bit similar to Nitrogen deficiency: the leafs loose the green color, but the difference is that the leafs will start to be affected on the margins first.
The micro-nutrients are: magnesium, iron and calcium.
The Magnesium deficiency main symptom is chlorosis, but the difference is that the veins are still green (so the chlorosis in called interveinal chlorosis)
Iron deficiency is spotted in younger leafs as it’s an immobile nutrient and it’s looking as interveinal chlorosis.
Calcium deficiency is very common, especially in rooms that are not well ventilated. The symptoms are necrosis at the margin of the leafs and curled leafs. Calcium is immobile.
Here is the video explaining it all:
If you are looking for a more detailed explanation that also talks about pests and other nutrient deficiencies you can watch this e-Grow webinar: