Increase air circulation and cut back on water. Moss grows in wet, damp conditions. Put a small fan near the seedlings.

Jane

Sounds like algae rather than mould but the cure is the same. See above.

NO! Don't use straight hydrogen peroxide. You'll kill everything. (Well, you can use it to sterilize soil before you plant.) I water with 4 tbsp/gallon to prevent damping off. As noted, you probably have algae, which is not a threat to your seedlings, but I always find such growths a little odd in what is supposed to be sterile medium. You could also just cultivate the surface lightly to break it up. Algae doesn't have roots, so it isn't sucking up nutrients that you'd like your seedlings to get. Also, be advised that peppers are always very slow to germinate.

I myself find that algae is rare indoors. I have many houseplants whose soil surface I keep moist (catnip!), and I never get algae on them. But the spores are certainly carried by the wind, and moist pots outdoors almost always have algae on them, as do rocks in my creek. I guess it depends on how well filtered your indoor air is.

Thanks for these insightful answers, I had not thought of algae but this makes perfect sense! I had been giving them the perfect environment. Good to know that algae are not a threat to the seedlings. Will follow your advice.

When I was using clear plastic pots I had algae take over the entire pot, including down the sides, because the sides were translucent and transmitted enough light to support algae growth. That killed the seedlings. I am not sure by what mechanism. I discontinued the use of clear pots.

Physan 20 can kill algae, but if it is too strong it can also kill seedling roots. Before I throw away all of my clear square orchid pots I may run some more experiments with Physan 20.

ZM