Not enough space for seed trays in house, would they be ok in greenhouse?

[iwouldgoouttonight]

I've got one of those plastic greenhouses from Wilkinson's - I normally plant bedding plant seeds inside on windowsills and put them in the greenhouse in May when they're almost ready to be planted in the ground. But I've got a bit overexcited with seeds this year and have too many for my windowsills inside. So I put a tray of nasturtiums and a tray of cosmos in the greenhouse. They're now looking very wilted and not happy, but I don't know whether that's because the greenhouse is too warm for them in the day or too cold for them at night iyswim.

Have I killed them do you think? Or do you think they'd be ok if I put them outside in the day and in the greenhouse at night? Will the greenhouse protect from frost??

Depends where you are, and how cold. They were watered presumably?

Is the greenhouse opened up during the day? Yes, or put them out if it is sunny, and in greenhouse at night. Should protect from frost unless it goes bitter cold.

My nasturtiums have always done fine outside (NE England but sheltered)

That's not a greenhouse, that's a blowaway.

Nasturtiums and cosmos don't need to be indoors. But if you sowed them indoors you need to harden them off before they go outside.

Thanks all. I think it was because I'd forgotten to open the greenhouse when the weather suddenly went really warm, I've been opening it every day since then and watering regularly and they're perking up a bit. The ones inside look a lot happier though.

I don't have much luck with sowing seeds directly into the ground outside, I don't know if it's birds or slugs or some other underground insect but the seeds seem to vanish and not grow at all.