[FiB]

I finally caved in and bought a windowsill heated propogator.....   (We don't keep a hot house here, so after a couple of years of rotted seeds or non germinated ones...).  All seeds sprouting merrily, but i don' know what to do next re vents/ taking lids off! When do seedlings need less humidity? For example tomatoes are already looking leggy and I don't want them to get rotten stalks..... Many thanks for any advice

[Ina]

I tend to take them off the heat and cover as soon as they have germinated and show a bit of green. Saying that, at the moment it's so bl**dy cold again that I am tempted to put the heat on - although I've already pricked them out (that's kohlrabi seedlings)...

[pgkevet]

I had a lot of trouble using covered propagators for seeds for the very reason of damping off. I think they're best used for cuttings where you really do need humidity to keep those cuttings from losing water while they root.

For seeds that need more heat than my greenhouses or sunroom area off the living room and woodburner I do use a heated tray at times..just no cover. For the rare senstive plant that does need increased humidity then a pebble tray.

you also have the issue of matching ambient temp/bottom heat with available light so most of my stuff that germinates on the sunroom windowsills goes into the greenhouses as soon as frost safe temps....I'd rather they grew a bit slower but more robust.

The only greenhouse i have a frost stat in is for my citrus and temps and humidity are higher in there for various reasons.. I lost several seedlings there last year damping off too. they're much happier in the cold house

[FiB]

Thanks both... Do have a conservatory but got a min max thermometer in there and range is 4 - 26! House is a steady 14 except couple of hours of wood burner in living room.   Will take lids off? Propagating is one of my goals this year too so that's good to know too. Thanks xxxx

[pgkevet]

You're not an impossible distance from me. I'm just outside llanfyllin So if you're passing here in a few weeks time there's a good chance I'll have some spare seedlings about 'cos i tend to put up way more seeds than the greenhouses have room for and there is no passing gate traffic to sell it at; I usually end up chucking extras and would rather give them away.

Outdoor crop stuff is another matter - I have more room than i have stamina to cultivate.

We keep the house way warmer than you - wifey is a hot-house dear while i sweat in t-shirts indoors. Fortunately we have more than enough timber on the land so keeping the burner fed is only an issue from the cutting and processing pains

[Lesley Silvester]

I start my tomatoes off on a sunny window sill in my heated house. I grow them one seed to a small pot and fix a clear plastic bag over each one until they have germinated. It seems to work.

[Somewhere_by_the_river]

If dampening off is a consistent problem it would be worth investing in some vermiculite. It's not too expensive and you only need cover the top of the compost (try ebay, this was a good deal - http://www.ebay.co.uk/itm/370919248724?var=640134327020&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649). I've had years of success with covered propagators, but have found that some seedlings do suffer from dampening off more than others - usually the smaller seeds in particular, with tomatoes being a prime candidate. Our house is not the warmest either (more so since moving, it's bigger!) so I only ever start things off in the latter part of the suggest 'range' of months to do so (we're in West Wales).

What compost do you use? That can make a difference too. I tend to use multipurpose organic and peat free, but whilst it's fine for more robust things like squash seeds, again, things like tomatoes don't seem so happy in it... not that it bothers the 'volunteers' that seem to come free with the content, they are. clearly, made of stronger stuff!! Try a compost specific to seed growing - they are often sterilized, which helps, and there are organic versions too.

As for when to uncover - cool is definitely better than too hot, so start with turning the heat off once they get their first full true leaves, but leaving them covered for a week or so, then take the lids off during the day and back on at night and so on. Judge by how they grow, if they've got this far they want to keep going, just make sure they have plenty of light on all sides by turning them regularly if they are on a windowsill (I'm sure you know a lot of this, just want to give a fullsome answer!).

Hope they do okay