Best Practice re: Propagator Use

Hi, I have been growing my vegetables from seeds in a propagator for a few years now, but there is one thing I am confused about.

When should I open the vent on the propagator and by how much?

In previous years I have almost daily poured away the condensation that forms on the lid, should I do this?

Anybody tell me what the best practice is.

Many thanks

Mark

I'm using a heated window sill propagator with 7 mini trays.

Another question I have is last year on a couple of the seed trays when the seedlings had germinated I took them off the heat and removed the lids, within a few hours the seedlings had flopped over, I quickly replaced the lid and luckily they recovered.

What did I do wrong? Did I remove the lid too early?

Also any more views on the general ventilation of propagators?

Thanks

Mark

Dunno if I'm doing it right ... but my method is:

Sow, lid on, vent closed.  Condensation allowed to run back on to the soil.

As soon as germinated vent open, lid kept on, tray kept on propagator.

Larger seedlings (Toms, Cues etc.) will be pricked out within a few day. I take the lid off for a day or so before pricking out so they acclimatise to less humidity.

For smaller seedlings, which need to be in the seed tray for longer, there is risk of damping off, so I remove lid after a few days, and move the tray off the propagator (and into greenhouse) to encourage them to grow.  I only water the trays from the bottom (plunge in a bowl for a while, but they don't drink a lot, and it isn't hot enough, yet, to dry the trays out very quickly, so only need to water about twice a week).

But I've lost a tray of Petunias from damping off nonetheless - about 3 weeks after they were sown, and not quite ready / big enough for transplanting

What have you got growing there, markjp - it can sometimes make a difference

I'm growing Tomatoes, Cucumbers, Chilli & Sweet Peppers at the moment.

Also whats the best thing to do if a few seeds have germinated but the rest havent, do you take the lid off the propagator to avoid those that have germinated from going leggy and risk the rest not germinating or do you keep the lid on for a few more days to see if more seeds germinate?

I always thought that you waited for the first true leaves to develop on a seedling before transplanting. Have I got that wrong Kristen?

Mark

I generally wait until the first two leaves form, but only with the bigger seed as these are easily sown without crowding. As mentioned with smaller seed you may have to do this sooner as the seedlings are vying for space and can become spindly for this reason as they are blocking light from each other.

Always take the seeds out of a propagator or take the lid off as soon as the first ones germinate. This does not mean the others won't, but the first lot will be weak & leggy if you don't.