Hello! How do you do? I would appreciate your help with identifying which nutrient has become deficient among my tomato plants. Peat soil, pH ~5,5, not yet flowering, have grown for about 1,5 months. The deficiency symptoms are on the lower half of the plant (e.g. on the older leaves) Thank you very much ! --close please
What ratio and how often do you fertilize? Off hand it looks like salt buildup which can burn the foliage.
I haven't added any fertilizers yet, since the new peat soil which I bought was with fertilizer. (NPK + all micronutrients) Frankly, I do not know anything about salt and its possible toxicity.. I was thinking about Mg deficiency maybe. BTW, some plants with higher pH have fewer symptoms.
Fertilizers supply elements in salt form. Your plants may be getting too much of some element, the higher pH of the less affected plants point to that diagnosis.
Ideal pH for tomatoes is at least a point higher, around 6.5. You may be right about the magnesium deficiency, since that is probably the most common deficiency in tomatoes, but it is very difficult to supplement individual nutrients without serious testing. It's pretty rare I think to have a soil that is ideal for tomatoes specifically without added fertilizer, I would probaly start using some. Many growers have had good results also adding epsom salts to supplement magnesium (it's technically hard to combine into commercial fertilizers, so they're often short of it). A safer way to get your fertilizer might be to add pure organic compost at 50% of your container soil when first planting; then you can reduce your fertilizer requirements by at least half, since you know the organic half at least is coming truly "complete" levels of nutrients.
saltcedar: do you assume that it is nutrient toxicity rather than deficiency? What could it be then? mr. Hulse: I will add some full-specter fertilizer, but I think I will get some Mg salts as well to help plants recover more quickly. My tomato growing manual tells that the ideal range pH is between 5,5-6,5, so I assumed that I am in the clear. Guess I was mistaking. edit: perhaps it is manganese toxicity??