Vegetable Germination Period Cheat Sheet For Greenhouse Gardening

Last Updated on February 16, 2022 by Real Men Sow

They’ve taken almost 4 weeks, but I’ve finally got signs of carrot and beetroot germination (pictured) in the greenhouse. I’m putting this progress down to a few short bursts of sunshine which has temporarily brought the temperature of the greenhouse up.

Typically, the temperature has been between 2 and 8 oC during the recent cold weather, and according to some reports the chilly conditions are set to stay with us until at least the end of the month.

Do Vegetables Germinate In The Cold Winter

How will further cold temperatures impact our sowing plans? Well, all is not lost if you can find yourself some glass to sow under, whether it be a grand greenhouse or an old window laid on breezeblocks.

What’s The Ideal Temperature For Vegetable Germination In A Greenhouse

For many veg, the increasing light levels are more important than temperature. A good amount will germinate at between 5oC and 7oC, which means we can still crack on, excitedly ignoring the fact that it is darn cold.

Vegetable Germination Period Cheat Sheet

5 oC Germinators

Veg Germination Period
Radishes 3-7 days
Swede 6-10 days
Turnips 6-10 days
Cabbage 1-2 weeks
Cauliflower 1-2 weeks
Brussels Sprouts 1-2 weeks
Purple Sprouting Brocolli 1-2 weeks
Kale 1-2 weeks

7 oC Germinators

Veg Germination Period
Carrots 2-3 weeks
Beetroots 2 weeks
Parsnips 2-4 weeks
Leeks 2-3 weeks
Spring Onions 2-3 weeks
Chard 2-3 weeks
Globe Artichoke 2-3 weeks

Vegetable Germination Tips

Radishes, Chard, Leeks and Kale Germination

As well as the beets and carrots, I’ve got radishes, chard, leeks, and kale in the greenhouse, all of which have battled the elements to germinate. They took their time, but I can understand that. I’m not the fastest of movers in the cold either. Today, they’ve been joined by sowings of sprouts, PSB, more carrots and leeks and spring onions.


Some books recommend a steady 10 oC for pea germination. However, I’ve also sowed peas, mangetout, and broad beans during the middle of February, and these have germinated, although with differing levels of success. I saved seed from a Heritage Seed Library early pea called Essex Star last year, and they have all germinated, as have the Real Seeds Golden Sweet mangetout.

The Telegraph maincrop pea from the same company has not done so well, with only a handful of germinations. Hopefully, it is just the maincrop in them holding the Telegraphs up.

Protecting the Sowings From Cold, Hardy Radish and Out of Date Seed

I have been covering the sowings with horticultural fleece and bubble wrap on particularly cold nights, but what’s interesting is that I don’t have enough to cover my radishes, yet they’ve happily germinated, and look very healthy. Some days have been near enough zero degrees in the greenhouse, which makes these seeds a real winner in the cold weather.

Furthermore, the seeds are two years out of date, which also goes to show that just because the packets say they’re unlikely to be any good, it is still worth a sow.

I’ve always been a half glass full kind of chap, so I’m still adamant that the newspapers, the Met Office, and Carol, the nice BBC Breakfast weather forecaster and my favourite in living memory, are all wrong and Spring will return after its fleeting appearance a fortnight ago.

Still, I’m reassured to know that even if Spring doesn’t come back, I’ll still have something growing.

Real Men Sow
Real Men Sow

Hello, I’m Pete and I’m currently based in the west of Scotland, in a small place called Rosneath, where I’m exploring my garden adventures. I personally started gardening around 6 years ago and initially, I started out by growing my favorite fruits and berries, such as strawberries, Raspberries & Gooseberries. Since then I’ve added a lot of vegetables and working closely with my neighbor, it’s been a lot of fun.

7 thoughts on “Vegetable Germination Period Cheat Sheet For Greenhouse Gardening”

  1. I haven’t begun seed sowing yet except for peas, a few of which have shown their faces, but the broad beans refuse to germinate. I’ll start sowing in earnest in April, hopefully spring will have decided to return by then.

  2. Hi Elaine, thanks for your comment.

    Still exploring the potential of my greenhouse so sowing earlier than I normally would.

    My broad beans have been the same. Only ones I’ve managed to get going were started on a windows.

  3. Radishes are such tough little things aren’t they. I’m convinced they could grow anywhere at anytime! I’ve only just sown my beetroots this weekend as I’m just not sure of the weather this month at all. I’m hoping that by the time they germinate I can get them into the cold greenhouse to toughen up and then plant them out when it’s less rainy (which might be never in this country!!) I’m dreading sowing anything directly outside this year so will probably start everything off in pots. Just not sure what to do for the best really.

  4. Hey Anna,

    When I sowed my beets, I did so in modules but at the same time covered a row in the veg patch with glass. Hopefully this will warm that row up enough so that I can put the beet seedlings under it when they’re ready.

    Just an experiment really, but hopfully it’ll work and I”ll have early beets 🙂

  5. I’ve got some broad beans in pots waiting to germinate, ones I tried overwintering just rotted. 🙁
    Sowed up some parsley, beetroot, turnip, lettuce and coriander. I’m in France 750m up in the Auvergne so gardening is a little different here! It’s also our first gardening season here so it’s going to be a steep learning curve. Eg locals don’t plant out potatoes until late April early May.

  6. Hi David, thanks for your post.

    Never tried broad beans over winter, but I did see Bridget from sowandso .com grew them in a pot last Autumn and left in her greenhouse until now. They look great, really healthy.

    Can see from your blog how things are very different! How do you find growing on a hill? I’ve always had a soft spot for veg being grown on the side of a hill.

  7. Hi Jono
    Growing on a slope is ok except when you are trying to erect raised beds. Lots of soil removal and a spirit level required.!
    But the strawberry bed on a slope is looking good. Broad beans are now just emerging from their pots, sowing another lot today ‘The Sutton’.

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