Brassicas
Brassicas contain minerals, nutrients and antioxidents making them quite a healthy go to crop for kitchen gardeners. They form part of many dishes including Sunday roast, salads, stir frys and trendy main dishes. This group of veg plants come from the mustard family.
Fun fact: the Celts farmed cabbage from across mainland Europe and the UK as long as 4,000 years ago, calling it 'bresic', which is probably where the word brassica comes from. Not all brassicas originated in Europe but now we're lucky enough to have them all in grocers and supermarkets. As there are so many plants in this category, they will be paired or grouped below.
Brassicas prefer alkaline soil, many can handle neutral but acid soils will damage or even kill the plants. These plants also respond well to nitrogen feed just like alliums. Young plants can be a draw for pigeons, insects and rodents, while the more developed plants attract butterflies such as the Cabbage White. The caterpillars eat the leaves, leaving you with a plant full of holes so netting, companion planting or a poly tunnel is often advised to ensure you have a decent harvest. So gardeners may also grow one 'sacrificial' plant that they do not protect as the majority of pests will migrate to that weakened plant. If you do this just make sure that plant is not touching the others.
Another issue is cabbage fly, which tend to go for the lower parts of the plant and the roots. If you see a blue tint to your brassicas (unless growing a purple/blue variety) this could be a sign. Brassicas, especially cabbages are susceptible to club root, which is a fungal infection causing swelled roots and stunted plant growth. For more information look out for articles or videos on dealing with pests and diseases.
Cabbage, Spring Greens (Collards) and Kale
These plants are being grouped together as they can be grown and eaten in a similar way. First up are cabbages, with a variety of cultivars for a range of cuisines from east Asian, roast dinners, salads and more. The main types of cabbage are the greens, reds, Chinese and Asian. The last two are similar to each other. There are so many varieties to try here all with their own unique flavour qualities.
For a year round supply sow undercover from February to April and outdoors April to August approx. 2 cm (4/5 inch) deep. Cabbages like to be well watered and to have nitrogen rich soil/feed. When planting out in the final position leave around 30 cm (1 ft) between plants and 45 cm (18 inches) between rows, if applicable as they can grow large.
Spring greens are pretty much a loose cabbage that hasn't fully formed the heart yet. Plants out seedlings from September - late October/early November depending of your climate and you can start harvesting from March onward. They will grow very slowly over winter so make sure you give plants time to start growing before your frosts set in.
Lastly, Kale has a wide sowing window from February to June but keep them undercover until around May depending on your last frost date. You should be able to start harvesting from October to the new year. Kale enjoys the soil conditions of other brassicas with the bonus that it is slightly more resistant to pests. Kale grows well together or in other planting methods. In the final position for both Kale and spring greens allow around 25 - 30cm (10-12 inches), as they are not as wide of cabbages.
Cauliflower and Kohlrabi
Due to the UK climate cauliflowers have two windows for sowing. Sow in pots or a propagartor undercover around 2 cm (4/5 inch) deep, from mid-February to May, planting out after frosts in (May through to July). A second sowing from October to December, in alkaline or partially alkaline soil in a sunny spot. The more sun they get the better they will do. You should be able to start harvesting after 7-8 months as they take a longer time to fully develop than other plants.
Cauli's come in many different varieties, colours and shapes, from the well-known green leaves with a white 'fluffy' head, coloured heads, spiky Romanescos as well as specific cultivars that have been bread to be bolt-hardy or disease resistant. Before you put seeds in just check the variety is suitable for your climate. For a climate guide, check our page.
It may look like a vegetable crossed with a creature from the deep sea but Kohlrabi has a mild broccoli taste. It is a good grower in the right conditions, in a full or partially sunny spot, so do not grow in a full shaded area. Kohlrabi is more resistant to drought and hot spells than swedes and turnips. Sow from mid-February to August around 1.3 cm (1/2 inch) deep and ideally undercover to start them off before transplanting outside. You can sow direct in warmer weather, or a warmer climate. Space approx. 45 cm (18 inches) apart in their final growing spot as they will grow out. Plants will be harvest ready after 3-4 months from late May/early June onward.
Sprouts and Broccoli
Sprouts look like tiny cabbages but have a stronger taste, which can be mellowed with a spot of gravy or malt vinegar. Sow throughout spring from February to May (ideally undercover until May) and plant out May to June. Sprouts can take up 6-7 months to mature but you should be able to start harvesting from late August throughout the autumn and winter. If sprouts are grown in unsuitable soil (non-alkaline) they may produce open buds. This is known as a 'blown' sprout, to avoid this make sure they have nitrogen rich soil with a feed. You can grow in rotation after legumes or with legumes in square foot gardening.
You can grow broccoli in a sprouting variety (bushy with small heads) or the typical larger head variety. Much like cauliflowers broccoli is now available in different colours. Sow from February to June moving seedlings outside from May onwards, or after the frost risk for your area has passed. Sow direct outside from May due to the soil warming up as summer approaches.
Broccoli can be harvested throughout the summer from July - September with this window extended in warmer areas. Like all brassicas, they are a favourite, not just to us but to many pests, so netting or caging is recommended for any of the above.
Turnips and swedes (rutabaga)
Belonging to the brassica family, these two could easily be in the root veg section. Turnips and swedes are tap root plants much like beetroot or dandelions. Sow turnips from February - August and harvest from March onwards. For big turnips space 20-25 cm (8-10 inches), or for smaller ones, like I prefer space around 15 cm (6 inches). For a potential 5 week success try specific variety designed to grow fast such as Tokyo Cross, whereas Green Globe tend to do better when sown later in the year.
Swedes (Swedish Turnips) tend to be bigger so require longer to grow. Sow in May and June and harvest from August throughout the autumn. Turnips and swedes store much longer than the rest of the brassicas. To do this keep in a dry, dark, cool place much like alliums. These two do suffer from the same pests, but as more of the plant is underground tend to fair better.
