Most gardeners think it’s too early to sow when everything’s frosty outside, but to ensure the most productive garden, it’s actually the perfect time to get key vegetables started.
Onions
Garden-grown onions are in a league of their own, and starting the preparation of a homegrown meal by chopping into your own handsome bulbs is always a pleasure!
You can start onions from sets (immature bulbs), but I grow most of mine from seed. It’s cheaper, and it also means they’re far less likely to bolt, which is when they flower and go to seed before they’ve had a chance to produce a useable bulb.
I sow my onions into plug trays with fairly large cells which will support the seedlings till it’s time to plant them out in spring. Fill the trays with all-purpose potting mix, screened to give a finer texture for the small seeds. Firm down the potting mix to leave a slight depression.
![Onions in a plug tray]()
Sow clusters of onion seeds into a plug tray to grow on in clumps
Sow a small pinch of seeds into each plug, aiming for about six seeds in each. Onions can be sown any time from about midwinter to early spring, but by sowing them nice and early we should get a slightly earlier harvest. That means ground space will be freed up that little bit sooner, giving the opportunity to grow a follow-on crop of, for instance, kale or chard from the second half of summer and into autumn.
Cover the seeds with a little more of your screened potting mix, then water them. You could use a watering can with a very fine rose attached to avoid blasting out the potting mix, but I find a pump-action, handheld spray bottle does the job nicely. Or another option is to sit the tray in a reservoir of water so moisture is drawn up from the bottom. Once you can see that the potting mix is moist at the top, lift out the tray to drain off.
Onions don’t need high temperatures to germinate. You could leave the tray in a greenhouse or hoop house to germinate if you wish, but bringing your sown seeds indoors speeds up germination and increases your chances of an earlier harvest. Once the seedlings appear, you can take them back out into a greenhouse or hoop house to grow on.
Once the seedlings have germinated, thin them out to about four or five per plug. In spring they can be planted just as they are, as a cluster of plants, with each clump about a foot (30cm) apart in each direction.
![Chilies under grow lights]()
Grow lights help chilies grow strongly when light levels are low
Chili Peppers
Chilies need a long growing season to produce a decent harvest, so it makes sense to start them off super early if you can, particularly in cooler climates. They need warmth and, once they’re up, they’ll also need additional light to get them growing strongly. If you can offer them that, they’re good to go now!
This year I’m sowing what’s left of some seed packets opened last year: a mix of relatively mild (or at least not eye wateringly hot!) but really productive varieties that will give me lots to harvest for livening up mealtimes. These slightly less spicy varieties also tend to crop sooner, which in my often unpredictable climate is no bad thing in the event of a washout summer.
The trick with chili peppers is to keep them warm at all stages. To help with that, bring your potting mix indoors the day before sowing so that it can warm up to room temperature. This way the seeds won’t get shocked by the cold and can nestle into a far more agreeable blanket of warmth.
For chili seeds I fill small pot with a mix of screened peat-free potting mix and an equal amount of coconut fiber, plus a handful of perlite for good drainage. Be careful when mixing in perlite as it’s not great to inhale – wearing a face mask while you’re mixing is sensible.
Space out your seeds evenly across the top of the potting mix. Don’t try to pack too many into your pot, or the seedlings will be hard to separate when they’re big enough to pot on into their own containers. Sowing several in one pot means they’ll take up less space early on, and avoids wasting potting mix if any fail to germinate.
Cover the seeds with a little more of your potting mix, label the pots, and water them.
![Humidity dome on a heat mat]()
Keep chili seeds warm to encourage speedy germination
Chili peppers germinate quickest in the warm. A simple humidity dome placed on top of a heat mat, set to around 75ºF (24ºC), works well. That’s positively toasty, and should give reliable and speedy germination.
If you don’t have a heat mat or a humidity dome, then another option is to secure clear plastic over the top if the pot with an elastic band and position your pots in the warmest spot possible – near a boiler or hot water tank, for example, or on a sunny windowsill – and keep them as snug as you can.
Once the little seedlings have popped up, they’ll need plenty of light. A set of grow lights, turned on for around 12 hours a day, is perfect. Extra light is really important at this time of year when natural daylight is weak and days short.
If you can’t offer extra light, consider starting your chilies a month later so they can take advantage of what will be, by then, rapidly lengthening days. At this point you could set up a natural light box using white or foil-lined card to bounce back the available light for a more even result.
My chili seedlings will go out into my greenhouse in mid-spring, once it’s a bit warmer and there’s definitely no chance of frost.
![Cauliflower]()
Cauliflowers can be sown from midwinter to ensure a continuous supply throughout the year
Cauliflower
ith their brilliant white heads and hearty eating, cauliflowers are the cream of the crops! What I especially love about them is that you can enjoy cauliflower harvests for months on end – from early summer through to autumn – depending on when you sow them. I sowed my last batch of cauliflower seeds in autumn, and they’ll be ready to plant in spring and give the very first harvests of the season.
But sowing now, in winter, gives us the next precious harvest. Scatter a small pinch of cauliflower seeds across the surface of a pot of all-purpose potting mix, cover them over, label, and water.
Like other cabbage family crops cauliflowers don’t need much heat to germinate – a windowsill will be fine. Once the seedlings have come up, they can be carefully teased apart to pot on into their own plugs or pots. Of course, you could sow directly into plugs instead, because they are very reliable germinators, but sowing into pots first makes the best use of indoor space. Transfer them to a greenhouse, hoop house or cold frame once they’ve been potted on.
![Winter sowing in milk cartons]()
Milk cartons can be left outside to let seeds germinate in their own time
Leeks and Cabbages: Winter Sowing into Milk Cartons
If you don’t have a greenhouse or cold frame, an alternative way to enjoy a super-early start with cauliflowers, cabbages, leeks and many other hardy, cool-season crops is to winter sow them using old plastic milk cartons.
Punch holes into the bottom of your milk cartons using a screwdriver or other pointy tool then, using scissors or a knife, cut the carton most the way around, about halfway up, leaving a hinge of plastic to connect the two halves and stop the top from blowing away.
Fill the bottom half of the container with potting mix, then sow your seeds. Label them and then secure the top half in place with some heavy-duty duct tape.
![Winter sowing in milk cartons]()
Many hardy vegetables can be winter sown into milk cartons
Place the cartons outside in a bright, relatively sheltered spot to germinate at their leisure. This may not happen for several weeks, but rest assured the seedlings will come up when they’re good and ready, and conditions are right. The milk carton offers extra protection that will speed things along by as much as three weeks on seeds sown directly into the ground.
Once the seedlings have come up, carefully prick out (transfer them) into their own plugs to grow on. This will prevent them from getting overcrowded, so each seedling can keep growing smoothly till it’s time to plant in mid-spring.
You could also try this method with early salads such as lettuce and other hardy salad leaves. Once you’ve finished with the cartons you can just rinse them out then recycle them as usual, so there’s no wastage.
![Garlic cloves]()
Garlic can be planted from autumn until as late as midwinter
Garlic
Garlic is my absolute favorite vegetable! So far we’ve been sowing into pots, plugs and milk cartons, but this is one plant that can go directly into the ground so we can get our hands properly muddy!
Garlic needs a period of cold weather to stimulate each planted clove to divide up into multiple cloves to produce a new full bulb. I’ve got a bit behind this season with my garlic, because I normally aim to get my garlic in the ground towards the end of autumn, but midwinter is still a really good time to plant because much of the coldest weather is still to come.
Garlic needs well-drained soil and a sunny spot. Improve the soil before planting with plenty of well-rotted compost. To plant, split the garlic bulb apart into separate cloves, then plant each one to a depth of at least 2in (5cm), pointy end up, spacing them 6in (15cm) apart in both directions.
![Garlic in the snow]()
A period of cold is required to help garlic form cloves
All you need to do now is water the garlic in dry weather, and remove any weeds as they pop up. They’ll put on a lot of growth starting from midspring, ready to harvest from early to midsummer.
It may be very early in the season, but now’s your chance to plan ahead for well-deserved success later on. Increase your chances of bumper harvests by taking a few moments to plan what will go where and when – and to help with that, be sure to check out the totally free, no-obligation 7 day trial of our Garden Planner.
