Tomato stress symptoms
I have some problems with my tomato plants (cultivar Moneymaker) that always develop the same stress symptoms around 24 days after you see the first seedlings emerging. Before that, they look healthy and fine. The symptoms start on the cotyledones and are then appearing on the older leaves (egdes of the lower leaf side get purple and there are yellow . Plants are growing in 1l of potting soil at 24°C-22°C and 70% relative humidity. The way the symptoms appear made me assume that it is a lack of one or more nutrients but that doesn't seem to be the problem. I tried different fertilizers (slow release, specific commercial tomato fertilizer, a general commercial fertilizer and half-strength hoagland solution) but with each of these fertilizers, the symptoms appear exactly at the same time as they do in unfertilized plants. There is also no difference in plant size, which makes me think that 1l of potting soil is providing them with everything they need at this growth stage. The rest of the conditions look pretty much normal and are used in many studies. I attached some pictures as well. Many thanks in advance.
Have you tried giving them a dose of Epsom salts?
If you live in Derbyshire, as I do.
I'd say carry on as you are. Black marks (like a bruise) on the stem of the plant may indicate blight.
If you try to give supplements such as magnesium (epson salts) you have to be careful. If it's not needed then excess Mg can lock out Calcium which may cause blossom end rot.
There's no need to fertilize the plants until the first tiny tomatoes start to form, then use Tomorite or similar
Wisdom is not putting it in a fruit salad.
Or of course it could just be the natural growing cycle of this variety. As the plant grows it slowly allows the lower leaves to senesce and die off
I think it is normal that the cotyledones are die off after some time but especially the patterns that you see on the leaves in the picture do not look as if they were part of the normal growing cycle. Maybe there's another person here that grows Moneymaker and can confirm that.
Many thanks to everyone for the great input!
I am no expert but I think :
1. The pots are too small.
2. The plants seem to be over-fertilised - no fertiliser required until the tiny tomatoes form and then only once a week
3. The humidity is too high
4. The small shoots on the main stem should be pinched out