Take the dome off and check the temps. Let the rockwool dry out some.
Sounds like a mouldy smell.
LOC NAR on probation Reviewed by LOC NAR on probation on . Rockwool question I'm starting some new seeds and they've popped just fine, but when I opened their dome this morning I noticed a vaguely sour smell. It's humid in there and it seems the smell is coming from the rockwool cubes. Is this unusual? I soaked the rockwool to fix the ph, buit I didn't think I needed to sterilize them (they are new cubes). Should I be concerned? Can I treat the little ones with h2o2 or something? If so, how strong a dose? Rating: 5