I grow giant cockscomb celosia from seed every year. I have a small house and must place the trays before a window in the utility room and before windows in the dining room. I usually lose a few every year to damp-off but this year I don't know what is going on.
They don't seem to be suffering from damp-off. The don't wilt at the stem and fall over. Rather they begin to droop, the top eventually touching the soil, forming a long arc. Then they stay that way and die. It doesn't strike in one tray, or in seedlings adjacent to each other. It's one here and there, until I've lost fully half of about the original 140 plants. I wouldn't have enough for the yard if I hadn't planted more 4 times now. (Assuming they don't all die)
As I have numerous trays in various locations I can experiment to see if anything helps. I have four different brands of seeds. No difference in loss rate. I have three different brands of seed starter. No difference. I have place them in sunlight and indirect light no difference. Warmer spots in house, colder spots in house. No difference. Less water, more water. No difference. Peat pots, paper cups, seedling trays, dome/no dome??no difference.
A nursery recommended a light sprinkling of captan on the soil. I tried this on some, not on others. No difference.
I've never had a problem anything like this in other years and can't figure out what to do differently. I'm posting this knowing it's unlikely anyone can help without seeing the seedlings and conditions but at this point I've got nothing to lose. (What I'd really like is to find someplace that sells the seedlings already established but for the large/giant cockscomb that seems hopeless, at least here in Ohio.)