I have always problems growing seedlings on the window sill. They come up fine but don't make very well the transistion to outdoors, even when I put them in shade first.
I did seedlings with peas in egg cartons because the mice are eating my peas out of the ground. They are wimps comapred to what I got before the mice discovered the peas.
My tomatoes are not looking good at all.
Do I drect seed tomatoes who does this ? Or chillies peppers aubergines?
If I would build a cold frame next year what does it do to the night temperatures? Or do I have to use a muck bed?
Angelika- Try putting a clear plastic or glass cover over the seedlings. If they're close to a window, and your night time temperatures are dropping with the season, the seedlings might be getting heat/cold stressed. What kind of soil and what kind of containers are they in ?
When you do seedlings on the window sill, what direction does the window face, and how many hours of DIRECT light do the plants get?
My suspicion is that they get less than 6 hours of DIRECT light, and between the double glazing and possible shade from the window frame, or bushes or trees outside the window, they don't really get the full intensity of the sun.
If there is little or no shading, and they get more than 6 hours of DIRECT sunlight, then it could be a "hardening off" problem. The indoor plants never experience wind. If they go outside all at once, the wind beats them up because they never produced stems and leaves strong enough, because they didn't have to.
I put an oscillating fan on a timer on my indoor starts. And then I harden them off by giving them small doses of full sun/full wind for the week or so prior to getting planted outside.
A google search for hardening off would get you a ton of good information.
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