Sounds like 'damping-off' to me? Seedlings are overcrowded and too wet, and a problem with the compost. If it is this, then unfortunately the fungus is parasitic, and you will need to dump them all - don't put in your compost! You will also need to sterilise/replace your trays/pots before re-sowing. Use a sterilised base seed compost. What does anyone else think? Have sown, Pak Choi, land cress, rocket and winter density lettuce, but not cabbage, directly outside this year without so far any problem. I don't think it is too late to sow any of the above directly into your veg plot - especially the winter density lettuce if you are south england or midlands.

I would be surprised if this is damping off, which usually happens when the seedlings are much smaller, and I haven't noticed it ever appearing as white mould. It is more likely just a bit of mildew on the compost. Don't sling the plants unless they are obviously suffering, as if it is damping off they will wilt and die very quickly and there will be no doubt about it. You could remove the top layer of compost and replace it, or you could spray it with fungicide, or even do both. Damping off is best treated with cheshunt compound, if you can still get it, and the best time to do that is when the seeds are sown or just after germination. But I haven't found that a bit of mildew on the surface of the compost hurts plants as big as yours - perhaps I have been lucky, we'll see what the others say.

Thanks for the answers. I think mildew was the culprit. A light scrape of the top layer with a plastic plant identifier then a day in the Sun to dry out a bit and everything looks healthy. Lettuce now 6" and cabbage about the same all looking good. Thanks again for the advice.

:))

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