Lids on seeds

The way I do it:
put lids or polybags over anything that I'm sowing indoors, and they come off as soon as the seeds have germinated, and stay off.

Once they've made it to the (cold) greenhouse they continue lidless.
Stuff I start out in the greenhouse is lidless from the beginning, cos they be hardy stuff

When I finally put the toms and peppers out, in mid April (usually, but depends on the weather ) I make a polytunnel over the canes down each side if frost is forecast. and then take it off again in the morning

Cheshunt compound has been withdrawn from sale and in fact becomes illegal to use after 30.11.11.

http://www.rhs.org.uk/Gardening/Help-advice/Garden-chemicals-and-pesticides/Chemicals

Can we please not resurrect the usual agruments.

I take a slightly different view.

I have lids on my 1/4 sized propagator trays. I used to use clear plastic bags before I had a propagator.

At germination I open the little vent fully.  I leave the lids on for at least two more days (depending on how the seedlings are doing). I find that many that have germinated have not got their roots down properly, so I want to keep them humid and not stress them (until they have a strong root).

However, the lid is stealing some light strength - on a windowsill the light is only from one direction, has come through both panes of double glazing, and the clear plastic seed-tray lid ... so I am very conscious of the left and stem growth of the seedlings.  This year has been particularly bad as light levels have been lower than normal, and my seedlings are noticeably more leggy than normal. I put a strip-light above then on for 8 hours during the night to try to help them a bit. If your light is good (e.g. in a greenhouse) I would be inclined to leave the lids for a couple of day to provide humid conditions for a bit longer.

Damping Off is a threat, but I don't sow my seed "forest thick" and I think that helps reduce the risk. I also only water seedlings with tap water - which doesn't have the muck off the roof that rain water has. I also only water from the bottom (put seed-tray in a  bowl of tepid water for 10 minutes, then let drain. I don't water at all until germinated (the lid prevents evaporation), and thereafter I don't "dunk" more than once a week at this time of the year

If you Google "Cheshunt Compound" & try & follow the links to buy some, they invariably come up as "out of stock", "currently unavailble" or simply a blind link.

ebay have but one solitary tin which may have slipped through the net, you'd expect there to be a lot of sellers.