I have many coleus starting out....about 700+ healthy looking young plants...some of which Im separating & transplanting into foam cups.
Im a bit concerned about properly water them. Pictured are a few I did 2 weeks ago and they are growing in size....but some seem to have leaves that are curling under, browning /yellowing a bit.
Im giving them plenty of indirect sunlight. Ive been monitoring these cups and only water them when the soil feels dry every few days ....but could I still be overwatering them?? Thanks!!

Im eventually & finally going to transplant them into the medium green plastic (pint size?) Pots where my son and I will sell them at our local Flea Market....a little fun business venture.

They look good.. other than the one in the photo maybe needs to be thinned.. looks crowded.. do you have a fan on them?.. they don't look drowned so I think you are OK with water.. if your lights are hot they may dry out quick

Im keeping them on this rack in front of my Bay Window which gets great mostly partial & indirect Sunlight . The smaller plants in trays I return to indoor greenhouse with the LED grow light at night because the window,area can be a bit chilly even with baseboard heat below.
I did thin a few of these out more....keeping it at 1-2 plants per cup for now. So I suppose with nearly 800-900 seedlings which are at different stages of growth I should expect a percentage of the plants to be duds or sickly....

H2O2
One thing you could do is add half a cup of regular Hydrogen Peroxide to one gallon of water.
This adds oxygen to the roots and also staves damping off and in warm weather, fruit flies.
I prefer to put some of this H2O2 water in a tray and then set my seed trays in and let them absorb water from the bottom. Then I remove that tray until the next day.
I also drain over watered plants and then add some H2O2. Have saved other drowning plants this way too.
Sidney