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hardy plant recommendations to sow/grow through winter in a "cool" greenhouse?

Hi all, any recommendations/advice on plants that will happily germinate and grow in a "cool" (eg above freezing) greenhouse through winter?  I started off some sweet peas early, in the late autumn, last year.  Anything similar worth trying?


  • ObelixxObelixx Posts: 29,853
    Germination is driven by temperature, moisture and light levels.  Some plants can be germinated early and will stand winter.  Others need a period of frost before they know it's safe to germinate and others need longer daylight hours to grow on well after germination or they will fail or become weak and spindly and floppy.

    Sweet peas and broad beans are best grown outside unless your winters are really vicious as they are hardy and will get too soft and leggy if cossetted.   They will also be sturdier for not having the reduced light levels of a greenhouse, especially one insulated with bubble wrap, which can lead to etiolation.

    Given the low light levels in winter it's best just to use the greenhouse to protect plants in pots that won't like having their tops or root balls frozen or sodden by winter rains and frosts.  Come late January or mid February, depending on how far south or north you are, you can start sowing tomatoes and chillies which benefit from a long growing season and can be potted on several times to make sure they grow unchecked and with strong, healthy roots. 

    Once light levels improve around the equinox you can sow many more plants both edible and decorative and for which there is no real advantage in owing early as they catch up really quickly as days lengthen and temps rise. 
    Vendée - 20kms from Atlantic coast.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • Thankyou, very informative!

    Re chillies and peppers, I did hear on GW one time that, if you trim them down, there is a chance they will over-winter and re-grow the following spring - thus giving you a head start on pepper and chilli crops (rather than growing from seed again and having to wait for plant maturity).  Do you concur with this, or have you found that they won't survive the winter to grow healthy crops again?

  • Yes, you can overwinter chillies if you remove all the leaves, cut all the side shoots etc back to within an inch or 2 of a node, and keep them protected and dry over winter. There's a bit of luck involved as very cold temps will kill them, and damp cold will cause grey mouldy stuff to rot them, as will poor ventilation. But if you manage to keep them over winter, they will indeed have a head start over Feb sown plants and you should get fruit earlier.

    I keep a handful of chillies over winter just in case, I usually lose about half of them. But then I'm terribly lazy, so I might have better luck if I made sure ventilation was better on good days etc...
  • ObelixxObelixx Posts: 29,853
    I've done it with chillies but by bringing the plants indoors and treating as houseplants as they need warmth to continue ripening the fruits which have already set.   They did carry on producing while the newly sown plants were getting to fruiting size but you need to remember to mist them.

    I have grown peppers successfully this year in our polytunnel but have to wonder if it's worth the time and space for the crop we've had - very few and very slow but tasty yellow peppers despite good soil, feeding and a seep hose to keep watering regular.   

    I'll probably stick to chillies next year as peppers are plentiful here but decent chillies are rare and just 2 or 3 varieties and none of them is what I would chose - espelette, Scotch Bonnet and unnamed but very mild. 
    Vendée - 20kms from Atlantic coast.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • Thanks both, I'll give it a go, you never know, I might get lucky!
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