"H Ryder" wrote in message
...
I'm just concerned as I think I should be starting to let air in etc
but I don't want to do that in case they dry out

What do you think

you could try this:
get a bucket of water, stand it near the seedlings, get a towel, soak the
towel, put one end of the wet towel into the bucket (weigh it down if
nec),
spread teh rest of the towel out and stand the seedlings on it. In theory
the towel will stay wet by soaking up all the water (it works by capillary
action, not gravity) and the seedlings will then stay damp by soaking
water
up off the towel.

The problem with that method I found was that it emptied too quickly. I
found a better way was to use capillary matting but in the supply bowl put a
upside-down jug with a slight gap, (wine making works well,) then it only
supplies when the matting starts to dry. The supply bowl level must be below
the base of the pots.

Slatts