Did you see the post I just made about paper pots featuring TP tubes here?
Subject: Recycled containers for seed starting and uppotting
The reason your tomato seedlings are running into difficulties — tomatoes are aggressive and will range wide spreading roots in search of nutrients. Their roots are at least as wide-spread as their leaves. So at this stage, they are touching the cardboard tubes. This causes nitrogen deficiency, as well as dries out the roots if the paper becomes dried out.
These seedlings look a little leggy and weak. Partly due to needing more light, I would assign blame also on the high temperature. They needed to be in high 70’s for good germination, but as soon as they sprouted, they would have been better off in 60’s to low 70’s. If this is the first time you are fertilizing, they are probably nutrient deficient as well in general from trying to grow too fast.
Yes, they are somewhat stunted, but you could uppot and plant them deeper — at this stage, I would go to something larger like disposable beverage cups. 9 oz or larger — like 12-16 oz — if a good size if you have the room, and you may need to deal with long roots and need the extra depth. Drop them in all the way to the bottom offer cup with drainage holes (I cut off the bottom corner in 4 places with utility scissors and cut slits up the sides with box cutter). Use regular potting mix which has some fertilizer added but NOT moisture control. Bury them up the stems to just below the true leaves (yes, bury the seed leaves). They should start showing signs of recovery and new growths in a week.
— BTW: IF you keep them evenly moist inside the tubes and the paper is kept barely moist, THEN you can create a condition that will promote “root pruning” and could grow healthy seedlings. I have used TPPP for uppotted tomato seedlings at first few true leaf stage. So IF these had been started in a smaller container and had a smaller/tighter root system, THEN they could have been uppotted to TPPP and buried up to their necks. I think however, that these would have long roots and would not fit.
Basil to the right is looking good. They can stay where they are (I think this is another sign that light is not sufficient for tomato seedlings.). Basil is also drought tolerant so as long as you start fertilizing them (1/4 strength for now) they should be OK.
Peppers are much better off started in a smaller container and kept very warm — 80’s if you can, use bottom heat source or place near the ceiling in this room. Seed starting temperatures for tomatoes and peppers are different And peppers can take a long time if conditions are not met ... as much as 2-3 weeks — I always have problems myself. You may be able to get these to sprout still if put in more ideal conditions, but it may take just as long to start fresh seeds that you know for sure haven’t died. I would not recommend using paper pots for starting seeds that take a long time to sprout like peppers. Also, peppers have the opposite kind of root growth — very slow-growing Small root system that can easily get dried out or drowned. You need to pamper them more. Pepper seedlings don’t need as much light as tomato seedlings, so once they have sprouted and have first true leaves
, this location in the low to mid-70’s with the basils might be OK.