How cold weather will affect your veg plants

If this is the first time you’ve grown veg over the winter then you might wonder what to expect as the weather turns from autumn to winter. So far, the weather has been fairly mild, and if you’ve got any veg growing in the garden then it has probably been doing quite well. Winter lettuces, chard, spinach and salad leaves will have grown quite a bit since being planted in early autumn, enough for you to be picking off a few leaves. Brassicas will have done a good bit of growing, with new broccoli plants and turnips getting themselves established well and plenty of new leaves appearing on kale. Meanwhile, veg planted in late summer, such as sprouts, cabbages and cauliflowers, will probably be reaching maturity over the next week or so and you may well have some sprouting broccoli appearing.

Now, with colder weather on the horizon, things will start to slow down a little. As temperatures drop to around 5 degrees celsius, plants tend to stop growing. This is good news in the weed department but what does it mean for your veg?

Well, most autumn veg will simply stop growing. They may still be putting down roots, but in terms of actually producing new leaves and getting bigger above ground, they’ll pause until spring. This is what is known as overwintering. They don’t suddenly die because it’s too cold, they just hang out in the garden until it’s warm enough to start growing again. This applies to kales, spring greens and winter greens, lettuces and broccoli.┬áSome autumn veg may still grow a little, but growth is significantly slower. Giant Red Mustard, Frills Mustard and the oriental leaves like Mizuna, Tatsoi and Pak Choi might keep going if it’s relatively mild. Other autumn veggies such as leeks and sprouts may already have reached maturity, so they’ll just sit in the ground and then when spring hits they would start to go to seed.

So, what can you harvest during the winter? Anything that has reached maturity (sprouts, cabbages, leeks, parsnips etc) can be left in the ground and harvested as soon as you need it. Salad leaves, spinach, chard and kale leaves can be picked off as you want them but make sure you leave a few on the plant so that they can get growing again later on. Alternatively you can harvest the whole thing if it is large enough. Broccoli planted in autumn will need to be left until spring as will spring greens, spring onions and winter greens.

Finally, for those more tender leaves it is a good idea to use horticultural fleece to protect them from frosts and snow. Whilst they are fairly hardy and should withstand the cold weather, it’s much better to protect them.