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October sowing in a greenhouse

REMF33REMF33 Posts: 673
I have not sown seeds in autumn before and this is my first autumn with a greenhouse. I have googled autumn sowing and it looks like there are various things, including flowers, that one can sow at this time of year in general - some outside, some in a coldframe. Can I assume that if something can be sown in a coldframe, it can be sown and grown in a greenhouse? Should I not sow things in a greenhouse which it is recommended one sows outside? (I am in south London.) 
Failing answers to these questions, what are people sowing right now? Is it too late for calendula?



  • At this time of year most cold-loving things will be fine in the greenhouse - just make sure you open it if there's a warm day.
    Not too late for calendula I don't think and you could try many other hardy annuals too. 
  • Busy-LizzieBusy-Lizzie Posts: 21,686
    Ammi is good sown in the autumn.
    Dordogne and Norfolk. Clay in Dordogne, sandy in Norfolk.
  • FairygirlFairygirl Posts: 52,064
    I don't sow much in autumn, because it just isn't worth it,  but the majority of plants which can be sown as seed  in autumn, are fine in either.   :)
    However, don't over cosset them if they're hardy annuals. Plenty of ventilation. In cold frames, many seeds/plants only need the worst of winter weather kept off them. Greenhouses tend to be warmer than cold frames because of the size, but they can get very cold at night, so vigilance is always necessary. 

    I was considering starting a Sweet Pea thread because so many folk like doing them. They're  a classic case of seeds which only need minimal protection.
    Too much warmth just encourages overly quick germination, and creates leggy weak etiolated plants.  :)
    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • Nanny BeachNanny Beach Posts: 8,427
    I never direct sow,lots of crops,winter peas,onions,garlic salad you can grow in the green house. My sweet peas sown  3 weeks ago are about 3 inches tall.ive got winter lettuce in there, foxgloves and lupin s for next year
  • Yes just saw your other thread about heaters - I wouldn't keep any hardy plants in a heated greenhouse.

    Just to clarify, I think @Fairygirl doesn't sow in autumn because of her location. In the south it can certainly be helpful in giving a longer growing season for cool-loving plants. In my conditions, calendula, for example, succumbs to mildew very quickly in summer and wouldn't be worth a spring sowing. 
  • FairygirlFairygirl Posts: 52,064
    I was assuming it was a cold greenhouse. Is it heated?  Heat isn't necessary for hardy annual seeds - does more harm than good, as I explained earlier   :)
    Yes - not really worth it here, but it does give an advantage if it's warm enough in spring to plants things out. Our season is much later -- and shorter, depending on the plant.  :)
    Half hardy ones are different from hardy ones though. Apologies if my earlier post didn't make that clear, but it's why I said that most seeds that can be sown in autumn are fine in either. 

    Sowing direct in autumn depends totally on soil, climate and temps.  :)
    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • REMF33REMF33 Posts: 673
    No, it's not heated. Was just asking about a heater to keep my options open.

    Thanks for all your comments.
    I am definitely going to try sweet peas in there. Also calendula, echinops and centaurea montana. Maybe some Antirrhinum. Delphiniums? I was going to try 'ordinary' cornflowers, but it might be a bit late. (I know they prefer direct sowing too, but I have had some succcess with starting off in pots.)

    Will also sow broad beans and edible peas, I think.

  • LynLyn Posts: 21,882
    I’ve sown my winter cabbage/Spring Green in there, I will plant them in the GH borders when the tomatoes come out. 
    Gardening on the wild, windy west side of Dartmoor. 

  • Cornflowers probably still OK, though they're pretty happy sown in spring and even summer in my experience. You'll generally get bigger plants from an autumn sowing, which with something fairly tall anyway you might not actually want.

    Delphiniums yes, and with looking at larkspur too, though germination can be fickle. 
  • Ohh thanks for this thread- I was not sure what to do either- so Anthirinum are ok in modules now ?
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