So I planted these beefsteak tomato seeds on May 8th and have started transplanting them into larger containers yesterday and the day before yesterday. They are kind of leaning over and I just wanted to make sure they are okay/ getting what they need. I keep them under LED lights for 16 hours a day. Are they a normal size/ colour for about three weeks in?
All in all, they don’t look bad. I would be worried if they were paler or more stretched (etiolated). If they are all leaning towards one side, they are turning towards a light source and you should rotate them regularly, e.g. daily.
It seems you transplanted them a touch deeper than they were in the original cells, which is good. This will encourage root formation on the part of stem that’s now in the soil and give them a good root system. You could go even deeper for the remaining ones and repeat the procedure whenever you are transplanting them again.
What I did notice, however, is that the soil in the square pots is surprisingly light / it seems dry? The plans in the third photo seem also a bit limp? I don’t think it’s transplant shock, it’s simply thirst. Remember that a freshly transplanted seedling often has a slightly damaged root system which may make water uptake difficult, so it’s better to ensure constant humidity. (Note I didn’t write “wetness”.) With seedlings at that stage, you will have to check and possibly water them every day, plus maybe turn them around, if they are “perky”, everything’s good.