Cabbage requires a substantial amount of nutrients and space in the garden. Growing plants is easy if you give your plants the right nutrients and protect them against pests. Cabbage is a great addition to a slaw or can be steamed with a little bit of pepper and butter. It’s definitely worth growing if you have the space for it. Our favorite Winter cabbage variety is ‘Savoy’.
WHEN TO GROW WINTER BRASSICAS
Remember that winter brassicas mature quickly. You need to allow enough time to see these plants through to winter harvests. Follow the seed instructions for your variety.
A general rule for growing winter brassicas is to sow them between April and June, then plant them out in June-July. You can keep yourself busy while your cool crops are growing by harvesting peas and beans, tomatoes, and courgettes!
Remember that winter brassicas like to start off in warm soils and grow in cool weather. Use this when you are deciding when to sow and grow them. Stick to the April-June months for starting off. You can start planting some varieties of plants sooner, as long as the conditions for planting remain warm (under glass). It’s not too late to sow your garden if you think you may have left it too late. You could still plant out plugs from reliable suppliers.
- Winter cabbages: Sow in April-May, transplant June-July.
- Winter cauliflowers: Sow seed in May, plant out late June-July.
- Sprouts: Sow early March-May, transplant mid-May to early June.
- Kale: Sow March-June, plant out late May-June.
- Sprouting: Sow in March for harvests in winter, or sow in April-May to transplant June-July, for harvests Jan-March. (You can sow as late as June for some later varieties.)
HOW TO GROW WINTER BRASSICAS
Before you start planting, consider the type of soil you have and take the necessary steps to prepare it.
- Soil conditions are important, as brassicas need firm planting. They like to be secure, especially those taller majestic kale and sprout varieties. Loose soil can make the plants wobble, tilt, or worse. If you dig before planting, make sure the ground isn’t too ‘fluffy’. It may help to firm lightly with your foot before you plant.
- These plants develop extensive root systems, and moisture supply is key to big yields. Soil fertility is also important, especially for cabbages and cauliflowers. Add some garden compost or well-rotted manure to the soil to ease compaction and boost water retention on sandy soils.
- Winter brassicas love nitrogen. Dig a high-nitrogen fertilizer into the top 8in (20cm) of soil before planting. (Be sure to fork in some more during September to top up the nitrogen levels.) For kale, the ground benefits from a scattering of a couple of handfuls of fish blood and bone.
- You also need to add lime if your soil is acidic – particularly for purple sprouting and kale. Winter brassicas, in general, prefer soil to be slightly alkaline. Cabbage plants are OK if the soil is neutral. Sprouts are also fine with a neutral pH, but it’s best to aim for pH7 or more (add lime if it is less than ph6).
HOW TO SOW WINTER BRASSICA SEEDS INDOORS
Growing brassica seedlings in soil covered modules protects them from slugs and flea beetles. If you protect your seeds undercover in a greenhouse or similar, you will get better emergence. The seedlings can be transplanted out without disturbing the roots in June-July.
Put one or two seeds in each section of the container with moistened potting mix. Multi-purpose potting compost is fine for purple sprouting and winter cauliflowers, and you can use 3in (8cm) pots instead. Sprinkle a thin layer of finely sieved compost over the top of the pots or tray and place in shallow water until damp.
Put your brassicas in a propagator set to 15-18 degrees Celsius, and they should germinate within seven to ten days. Both cauliflowers and purple sprouting prefer higher temperatures of 21-27 degrees Celsius (70-80 degrees Fahrenheit). Kale can germinate at a variety of temperatures, from 5°C to 30°C (41-86°F).
Thin out to leave the strongest seedling. Remove from the propagator. Find a place outdoors that is both light and cool to grow your seedlings until they are ready to be planted. This can be five-six weeks, depending on the variety.
HOW TO SOW WINTER BRASSICA SEEDS OUTDOORS
The traditional way to grow brassicas is to sow the seeds in a seedbed outside, and then transplant the seedlings to their final positions later. This is good for big cabbage and cauliflower varieties. If the soil has been prepped, this method is good to use. You should remember that while plants in cooler climates thrive, brassicas that are planted in winter need warmer temperatures in order to germinate successfully.
You can sow the seeds directly into the space where the plant will grow if you have enough room. For cabbages, the ideal seed spacing is 12-18in (30-45cm), depending on the variety. You should make drills that are half an inch deep and then sow the seeds thinly. Check the packet for recommended spacing For cauliflowers, plant the seeds 2cm deep and space them 6in (15cm) apart for miniature varieties and up to 24in (60cm) apart for larger types. Check the packet for recommended spacing.
To grow purple sprouting, plant three seeds in the ground at a depth of 2cm and 30cm apart. Thin out the seedlings so that only the strongest ones are left, spacing them 30cm apart. Plant the seeds half an inch deep and six inches apart in rows. To ensure your kale seedlings are thin, make grooves in the soil that are 1cm deep and sow the seeds thinly in rows that are 6in apart.
After planting your winter brassica seeds, lightly cover them with soil and make sure to water them.
It is better to plant the seeds in their final positions so that you do not disturb the roots, but it is alright to plant them somewhere else if there is not enough space. Transplant the seedlings when they are big enough to be handled safely. The amount of space you have available when planting is the determining factor.
HOW TO PLANT OUT WINTER BRASSICAS
The key to growing winter brassicas is timing—taking advantage of the gaps in the garden left behind as summer crops are harvested. It’s easy to transplant seedlings that were started indoors or in a seedbed, or that were brought in as plugs. The plants should be 3in (8cm) tall for ideal growth, but 5in/12cm tall for sprouting broccoli.
You can transplant around six weeks after sowing. To transplant these plants to their final growing positions, they should have at least five or six true leaves. Sprouts that have seven true leaves and are 4-6in (10-15cm) tall are ready to be planted in their growing spots.
To plant out seedlings that were started in pots, tip each brassica out of its pot and plant it firmly in the ground. Plant your seeds or plugs at the spacing distance that was recommended by the packet or supplier. For large cabbage, sprouting, and cauliflower varieties, the distance between plants can be 3ft (1m). The general rule for spacing plants is 12-20in (30-50cm) apart, although sprouts benefit from being spaced 2ft/60cm apart.
Push the transplants into the ground so that they are secure, then drench them with water to help them feel settled. This will help give them a good start. You could also try sprinkling fish blood and bone on your purple sprouting broccoli – this will give them a good start. Make sure to water your winter brassicas after you’ve planted them.
Leave for a few minutes and then plant as normal. A tip for planting when conditions are dry is to fill the planting holes with water and let the plant sit in it for a few minutes before planting it as normal. Water the hole thoroughly a few times before adding soil to make sure the plant has enough moisture.
WHERE TO GROW WINTER BRASSICAS
Space is the most important thing to consider when learning how to grow winter brassicas. Some kale, sprouting, and Brussels sprouts varieties can grow several feet tall, and the bigger cabbages and cauliflowers can grow to gargantuan proportions.
Brassicas are generally grown on light and sandy soils. You should have an efficient irrigation system in place, particularly for breeds with greyer leaves, as they are more tolerant of drought. Make sure you can easily get to water containers so you can keep your plants hydrated.
- Cabbages and cauliflowers do best in a sunny site with shade, and deep, fertile neutral-alkaline soil. Hopefully, you have followed our soil prep guide, but keep a close eye on ground conditions as the plants develop. Make sure the soil is firm and not loose.
- Sprouts also need a firm, fertile site – and shelter from strong winds (staking is recommended). They grow well in the sun or shade. Brussels sprouts have less foliage, so give some thought to quick-growing crops you can grow around them. This process is called interplanting. Lettuce, swedes, and radish make great companion plants.
- Kale is tolerant of most conditions apart from water-logged soil and too much shade. Make sure the soil is moist but well-drained and firm, and that plants will be secure.
- Purple sprouting plants like full sun but produce better heads in cooler conditions – too much heat runs the risk of them going to seed prematurely. They are hardy, though, and can handle temperatures as low as -12°C (10.4°F). Again, the right shelter and/or staking will be key to success. They prefer a heavy but well-drained alkaline soil.
If you don’t want to plant in the same spot for two years, make sure to rotate your planting. This rule applies even if you are growing up a different member of the brassica family. Choose a different location to prevent the possibility of root disease. Crops in the mustard family do well in areas where beans and peas have been grown previously, as those plants deposit a lot of nitrogen in the soil.
PESTS AND DISEASES
Pests to look out for when planting Winter Cabbage include the turnip root fly, the cabbage root fly, and the white cabbage butterfly.
Cabbage root fly.
The best way to avoid cabbage root flies is to keep the flies out of your crops by covering them with a fine protection mesh-like environment. To prevent intruders from sneaking in, you must make sure the edges of the mesh are secure. Cover them with soil or weigh them down with bricks or stone.
Cabbage root flies lay their eggs near the stems of seedlings. The eggs hatch, and the fly larva burrows down and eats the plant roots. You can prevent this from happening by placing cabbage collars around the base of the plants which the larvae can’t get through.
A natural way to kill root fly maggots is to apply a nematode pest control, which kills them at the larval stage. A product such as ‘Supernemos’ is effective as it not only attacks the larval stage of other pests such as leather jackets and wireworms, but also their eggs.
Cabbage White Caterpillars.
You should check the underside of the leaves for small yellow eggs periodically and remove them by brushing them off.
Cover the seedlings with something to keep out cabbage white butterflies.
This is a type of small worm that can be found in nature. It preys on the larvae of the cabbage root fly. There are already nematodes in your garden soil, and you would just be increasing their numbers if you added more. This product is safe to use around pets and children because it does not contain any chemicals. In order to get the desired results, you will need to apply the solution a few times. Although it may seem like a lot of work, it is actually very effective in protecting other crops from being damaged.
Cut off any yellowing leaves at the bottom of the plant. To get rid of whiteflies, spray them with water from a hose.
This is more likely to occur in established allotments or gardens than in new or isolated gardens.
Acidic conditions are favorable for clubroot development, so adding lime to the soil before planting can help prevent the disease. You will need to stop growing any brassica for at least 10 years in order to completely remove it.
Remove weeds from the ground by using a tool that moves back and forth. Hoeing can also help improve the soil by increasing the amount of nutrients that are available to your plants.
Check your plants regularly for any yellow, discolored leaves and remove them immediately. These leaves may contain diseases which could spread to the rest of your plants.
Since Winter is coming, farmers must make sure to pull up soil around cabbage stems so that the stems are prevented from moving around in the wind. Cabbage white butterflies will lay their eggs on your cabbage plants, so keep an eye out for them. Look under the leaves for the little yellow eggs and remove them by brushing them off. It’s easier to protect your crops with micromesh netting if you haven’t done so already. Be sure to keep any butterflies out while you’re doing it! You should hoe regularly to control weeds and stimulate growth in your plants. An oscillating stirrup hoe is a great gardening tool to have. This is an old-fashioned tool that is still very effective. Not only does hoeing remove weeds, but it also breaks up the surface of the soil, creating a fine texture, or ’tilth’. A good soil texture allows air and moisture to reach the roots of your plants, making them more vigorous.
A liquid feed given at around 14 weeks after planting will result in a larger harvest. Cabbage that is grown in the wintertime is very demanding and will require an extra boost of nutrients in order to yield a high-quality crop in a few weeks. An excellent feed can be made by soaking seaweed and poultry manure pellets in water over a couple of days. Pour the liquid through a strainer to avoid clogging the rose’s spout when watering.
The most ideal time to add a foliar feed is in the late evening or early morning. The stomata (small openings on the leaf surface) are open when the guard cells are swollen with water. Essentially this is when the plant breaths in.