Sprayed mid-day, perhaps?

Dan

yes, the directions warned about that. However, I thought if I turned the lights off they would not suffer.

The mid-day issue doesn't matter since these are apparently inside. What kind of plants are they?

Am curious, what kind of medium is that?

Ghost peppers, and Habaneros

started the seeds in hydroponic rapid rooters. moved to pots with soil then had issue with gnats and covered the soil with sand.

If the soil a plant is growing in is too wet the plants leaves will also wilt, just as they will wilt with too little water. A too wet soil keeps plants from uptaking moisture just as the plants cannot uptake moisture if it is mot there.

My thought is the mixture was too strong for the young, non-hardened off lvs, rather than my original 'cooked in the sun'. But it is just a thought as the resolution of the foto is inadequate for a decent diagnosis.

Dan

How long have they been in the pots? It could be the spray but could also be the difference in roots. Plant roots started in water have to go through a metamorphosis to become adequate for soil. Maybe a combination of both?
If you're having issues with gnats then your soil is too wet but a peppers first reaction to being too wet would be yellowing of the leaves, not wilting.