I started several seeds this month. A FEW of the seedlings that came up are now collapsing, after having grown ~1"; they look darker & kind of "wet" (as if they're mushy &/or "water-logged"); they certainly seem to be dying… Why could this be??—why would they start out healthy & then become "yucky" & start to die?? Is the soil maybe too moist? (but if it WAS, most of the seeds wouldn't have sprouted in the 1st place...right??) What should I do??
It sounds as though your seedlings may be affected by damping off, a soil-borne seedling fungus. (The spores can spread through the air, too.) Generally, damping off is more severe when conditions are cool and wet. Keeping the seedlings on the dry side should help. Providing more air flow (with a fan) to speed drying would also help.