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Greenhouse heating / winter growing

Hi everyone, apologies if this thread is in the wrong area but I just didn’t know where to put it!

I am a newbie to gardening against many of your folks and I would like to try and use my greenhouse more but dont know really where to start. I would like to start off some seeds for flowers and I have greenhouse heater but so many of the seeds require vast different levels of temperature.....any suggestions. Also do I leave the heater on all the time or for small amounts of time...These questions probably sound pretty daft I’m sure but I have yet to find a book on greenhouse growing that writes everything in easy to understand terms. Would love to hear your thoughts and suggestions on what plants I could start with. Im looking for strong colour and of varying heights and also perennial if possible.

thanks everyone in advance




  • sotongeoffsotongeoff Posts: 9,802

    It depends on what you want to grow-heating a greenhouse is expensive -so much heat is lost through the glass

    A lot of seeds can be started off indoors-in a propagator or warm spot- but is still rather early especially for frost tender plants as the growing on is the tricky part

    So Yvonne the main question is -what do you want to grow?

  • I dont really mind to be fair as long as its strong colours. My problem indoors is I dont have space so my only option is a greenhouse. 


  • sotongeoffsotongeoff Posts: 9,802

    Then leave it all till March-then you will not have to heat the greenhouse continuously and the natural temperatures and light levels will be higher

    Starting anytime now will not give you any advantage-be patientimage

    Are you looking for suggestions?

  • Busy-LizzieBusy-Lizzie Posts: 21,661

    Does your greenhouse have electricity? If so you can use electric propogaters to start seeds off. I have a cold frame in the greenhouse with a warming cable in it that I bought through internet. It doesn't use much electricity. I put seed trays in there. But I don't start sowing until March, as Geoff says, the light is better and the weather starts warming up. The other thing is that if you sow annual flowers too early and they get to a size that needs to be planted out but there are still frosts, you have to keep them in the greenhouse, re-pot them, feed and water them and they take up room. You can start off seeds on windowsills indoors too, either in a tray with a clear plastic cover or pots with plastic bags over them. I also use clear plastic food containers with clear lids.

    I don't sow many perennials, I find it easier to buy a decent plant and take cuttings or split it. Annuals that are colourfull that I have grown from seed - petunias, rudbeckias, snapdragons, nicotiana, ageratum, ipomea, french marigolds, lavatera, salvias, cosmos, zinnias.  You need to get a good seed catalogue like Thompson & Morgan or Suttons. You can look up the plants on Google. Something to do for the garden during the cold weather.

    Dordogne and Norfolk. Clay in Dordogne, sandy in Norfolk.
  • Hi Yvonne Parsons2,

    First off, better to ask and be a fool for a minute, than not ask and be a fool for life, so don't worry about being a 'newbie' no one's born a 'gardener.'

    2 books to recommend - Greenhouse expert by Dr DG hessayon, and RHS Growing under Glass by Kenneth Beckett - Both are extremely good books. I didn't know a thing last year, but have read the books, and re-read them, and am now ordering a greenhouse and know exactly what I want and can achieve.

    I've decided to go all out and get the Bio Green jumbo propagator with water trays and capillary matting. It comes with a thermostat, which means you can keep a constant temperature, though it may be worth putting a min-max temp thermometer in there just to check the soil temperature is as required.

    If you want to heat a greenhouse (I don't know costs of running as haven't got mine yet) I would suggest buying a thermostat that your heater plugs into, assuming it's electric. This will shut it off once at the desired temperature and switch on when too cold. As I've mentioned, I don't know how much it costs to run a greenhouse, but everyone keeps saying expensive. A thermostat should be a given me thinks.

    Going back to propagator, the Bio Green one comes with a polypropylene zip up case, which means heat is contained. This should also keep the price of heating down. It's over a meter long so can grow tons if you get the right trays. As people have said though, don't sow too early, as the light levels will lead to long, spindly plants, with the first true leaves a meter in the air if you're not careful with heat and light levels. image

  • Any help is hugely received as I really dont have a clue image

    Thank you

  • sotongeoffsotongeoff Posts: 9,802

    Then Yvonne I would keep it simple-buy,borrow, go to charity shops- get a bit of reading material-decide what you fancy-pop back on here and there is always someone who is willing to advise

    A greenhouse gives you many more options and is somewhere to hide when it is raining

    It is still very early in the gardening yearimage

  • All your advice is great, it really is. Ive always had the problem of wanting to do things right now and maybe its time to take a step back and wait ! So I will do as recommended and wait till March and will put my energy into preparing my veggie patch instead, even though I hate this job and the fact that my crops for the past 2 years have been dismall doesnt help...... I wish I could find a local gardening group that wasnt quite so much interested in people who already have some knowledge. I need a group that goes right back to the basics......

    so grateful for all your advice x


  • sotongeoffsotongeoff Posts: 9,802

    What happened to the little old man you mentioned before?

  • Also, good shout on ordering a Thompson and Morgan catalogue.

    Cosmos', Osteospermums, Nemesia's, Mimulus', Cerinthe Major, Echium Vulgare Blue Bedder,  Venidium Cape Daisies, Lobelias, etc, etc. These are some of my favourite annuals and the bees love the Cerinthe and Echium, though, do be ruthless in getting rid of seedlings of both, as they spread everywhere. 

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