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Germination Temperatures


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  • Germination Temperatures

    It's really confusing knowing when to sow, where to sow, unheated or in a propagator?
    Each vegetable is different, and the seed packets are vague at best.
    The list below just shows how little heat most things need to germinate ... personally I only give heat to veg from the bottom set; everything else is grown in an unheated greenhouse or on a cool windowsill.

    I've condensed a bit of the info below, in temp.order. You need to look at the full guide for optimum germination temps.

    Minimum temp necessary for germination (°C)
    lettuce 2
    onion 2
    parsnip 2
    beetroot 4
    broccoli/calabrese 4
    cabbage 4
    celery 4
    carrot 4
    cauliflower 4
    parsley 4
    pea 4
    radish 4
    broad bean - 5
    kale 5
    leek 7
    swede 7
    turnip 8

    bean – french & runner 10
    sweetcorn 10

    celeriac 10
    tomato 10
    courgette 16
    cucumber 16
    aubergine 16
    sweet pepper 16
    pumpkin 16
    chilli 18
    Last edited by veggiechicken; 21-04-2016, 11:14 AM. Reason: Link removed as no longer available
    All gardeners know better than other gardeners." -- Chinese Proverb.

  • #2
    I sowed two lots of chillie's 11 days ago in propagator and was about to chuck em out and start again when I noticed two plants just showing there heads today!
    My Majesty made for him a garden anew in order
    to present to him vegetables and all beautiful flowers.- Offerings of Thutmose III to Amon-Ra (1500 BCE)

    Diversify & prosper


    • #3
      Good info 2 sheds.

      Of course the trouble for most people seems to be consistency of conditions. So difficult if your at work ...the Suns out one minute and bakes them off and snowing the next! frosty at night etc. Indoors too warm so they go leggy etc etc I am lucky and have a heated greenhouse completely bubble wrapped with autovents. Even if you can create insulated box inside your glassshouse (maybe with a fluro strip light bulb underneath to provide heat if you have no propagator) it will help.(dont be electrocuting yourselves though!)

      Must say; i'm only suprised about broad beens..I just chuck em in the lottie and they come up even in late winter.

      You might think of adding the expected germination time to your list.


      • #4
        All information is useful, of course, but do you not think optimum temperature range is more helpful to most growers?

        If you sow at the minimum temperature many seeds never germinate and some that are viable just take so long that they rot or are eaten. It's not a good way to ensure a crop.


        • #5
          I found this really useful, as for the past couple of days I've been wanting to sow some bits and bobs, but the weather has been so up and down. Knowing what the minimum temp for germination is great so I know I can get going with some seeds, while holding off with some of the others. I'd also find it really helpful if anyone could help with a rough idea of germination times though


          • #6
            Good list Two Sheds. Thanks.

            Actually, is watering your seed with warm water a good idea?
            Would that aid in germination when the soil temp is low?
            Last edited by Mike and Louise; 06-04-2008, 06:09 PM.


            • #7
              Originally posted by Mike and Louise View Post
              is watering your seed with warm water a good idea?
              I think so. I give my seedlings a lukewarm soak instead of icy water straight out the tap.
              Last edited by Two_Sheds; 07-04-2008, 08:08 AM.
              All gardeners know better than other gardeners." -- Chinese Proverb.


              • #8
                Yeah, me too. Especially stuff that is going into the propagator, it takes less time for the heat to get through to the seeds if it's not having to warm up cold compost!


                • #9
                  Thanks 2 sheds - that's really handy! Let's you know what you can and can't get away with.


                  • #10
                    2 sheds that list is FAB
                    do you have one for minimum growing temps????
                    Thank you!


                    • #11
                      I water my parsley seeds in with freshly-boiled water from the kettle when sowing outdoors - they may have a low minimum temperature for germination but they take ages to get around to it unless you give them a kick up the backside! (A bit like men and chores - maybe that's why parsley only germinates for women who wear the trousers... )


                      • #12
                        The aim of my thread was to show that you really don't need to give everything heat to get it started ... and once things have germinated you can usually cool them down a bit anyway, eg out of the propagator and into an unheated greenhouse.

                        I try to grow things slow and hard (don't spoil them) not fast and floppy.

                        NB* I'm not talking about greenhouse crops like tomatoes and chillies, aubergines etc because I don't grow them. Me mam does for me. I mean outside stuff
                        Last edited by Two_Sheds; 08-04-2008, 05:57 AM.
                        All gardeners know better than other gardeners." -- Chinese Proverb.


                        • #13
                          Originally posted by Two_Sheds View Post
                          I try to grow things slow and hard (don't spoil them) not fast and floppy.
                          sort of treat em mean keep em keen eh!...sorry, won't let this descend in to euphemisms.


                          • #14
                            Originally posted by Two_Sheds
                            I try to grow things slow and hard (don't spoil them) not fast and floppy.
                            But if you grow some things slow, then you run the risk of never getting any return? Aubergines and peppers need long growing seasons.

                            Anyway, each to their own, start 'em quick harden 'em off later (ok that doesn't scan!).
                            Last edited by smallblueplanet; 07-04-2008, 07:24 PM.
                            To see a world in a grain of sand
                            And a heaven in a wild flower


                            • #15
                              There is a happy medium between slow and hard and fast and floppy - that's the point at which best germination and growth occurs at a steady rate. It isn't just dependent upon the soil temperature, but what you do when the seedlings are up.

                              There is an obsession with getting things to germinate as fast as possible but there's no point if the light or air temperature are completely unsuitable.

                              Equally, you have to realise that minimum temperatures will mean many of your seeds just won't make it.


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