Unheated Greenhouse

smarttart · 29 February 2012 at 9:22PM

Evening Peeps,

Today I have planted or rather sown, tomato, aubergine, chilli and sweet pepper seeds.

Now what I need to know is, can I leave them overnight in an unheated greenhouse or should they be bought back indoors in the evening ?

I think the coldest it has been during the last couple of weeks in the greenhouse has been 12*C/53*F.

If I leave them will it just mean that they will take longer to germinate or will the colder air kill them off.

I'm on the South Coast if that makes any difference.

kizkiz · 29 February 2012 at 10:27PM

I'm in the south east and my unheated greenhouse was -1 overnight at some point in the last couple of weeks.
It's way too early for planting out i think. Most chilli seeds need a constant 30c to germinate for instance

Biggreenfingers_2 · 29 February 2012 at 10:45PM

No its too early in the season to be putting those seeds in an unheated greenhouse. They need around 17+ degrees to germinate successfully. If you do happen to get them to germinate and then get frost then that could be the end of them.

Sambucus_Nigra · 29 February 2012 at 10:48PM

You can put them in an unheated greenhouse. They won't die. However they won't germinate yet either. All 4 of those need heat - the peppers and chillis and aubreys need most and the the toms need just a little more than that. I'd bring them in if you can, and put them somewhere quite warm. I crack open my chillis and peppers in a heated propagator and take them out as soon as I can see greenery.

smarttart · 29 February 2012 at 10:59PM

I've fetched them in

We've got a lean to greenhouse on a south facing wall so maybe that's what retains the heat. I've reset the thermometer so I'll keep an eye on it to see how cold it gets.

I thought perhaps it was a bit early to leave them out but my OH said they would be ok. I wouldn't have been very happy if we had no toms this year

Leif · 29 February 2012 at 11:26PM

Chilli seeds need a propagator with temperature of 20 to 30 C. Germination can take a week given heat, or months without. Seedlings will die if the temp gets down to 4C. You are best to germinate indoors, then transplant to small pots on a window sill, and grow until frosts are over which depends on where you live. Tomato is probably similar. I am sure aubergine is as sensitive too.

poppysarah · 1 March 2012 at 9:10AM

It was mild up until last night - but seeds should be started indoors if it's unheated.
Get a paraffin heater for when you want to put them out before the frosts have finished.

Last frost date depends on where you are in the country.

lagib · 8 March 2012 at 11:21AM

Much too early to leave seedlings of any kind in an unheated greenhouse but if you chance it i would cover with a fleece but do not let the fleece touch the seedlings. A bottom heated sand bed would help but you would need mains in the g/hse for that. I do heat my g/hse and struggle to maintain 49 degrees fahrenheit which is below the 56 i require to keep most tender plants alive.Bringing the plants into a warm house at night is safest.If you leave the plants in the house throughout the days you could put them in a light box.This is a cardboard box of suitable size with one long side cut out and the box covered on the inside with silver paper/bacofoil. Any seedlings placed in one of these will grow upright and not bend as any light reflects onto the plants.I have done this in the past with the box on the windowsill or supported near it.

Sambucus_Nigra · 8 March 2012 at 11:54AM

lagib wrote: »

Much too early to leave seedlings of any kind in an unheated greenhouse

eh?

Peas, broad beans, onions, leeks, beetroot, radish, lettuce, alpine strawbs, cabbages, kohl rabi - off the top of my head are all in mine and have been for weeks.

foxgloves · 8 March 2012 at 4:06PM

I've germinated my chillies, peppers, aubergines & tomatoes in a heated propagator on the loun ge windowsill, but I won't risk putting them in my unheated greenhouse yet. They come out of the propagator when they've germinated, then onto windowsill covered with one of those transparent plastic trays you get grapes, etc, in at the supermarket. Then they have a few days without the covers, before going in a cooler room, then out into greenhouse with transparent covers back on for a while. Sounds fiddly, but if I sow straight into greenhouse, I find they struggle to get going & most of these need a longish season. We're North East Mids & our pond has been iced over twice this week, so still seems a bit chilly for tender veg here.

allotmentor · 8 March 2012 at 4:13PM

Agree completely with Sambucus Nigra. Depending upon where you live, you could be sowing all sorts of veg. both under glass (cloche/unheated greenhouse):
beetroot, brussels, cabbage, carrot, cauliflower and peas
and even directly outside:
broad bean, leek, onion, parsnip, radish, salsify, scorzonera, spinach and turnip

Unheated Greenhouse

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