How To Grow Winter Vegetables Successfully
Get ready for winter!
Like September, March is a prime sowing month, only this time it is for autumn and winter vegetables. The cooler days make working in the garden a pleasure, so make the most of available time to set up the veggie garden for the next few months. The main winter vegetables to grow are leafy greens (lettuce, Asian greens, spinach and Swiss chard), easy root crops (carrots, beetroot and radishes) and the brassica big four – broccoli, cabbage, cauliflower and kale.
Make your own germinating mix for winter vegetables. Mix together equal parts of palm peat (hydrate first in a bucket of water), perlite and vermiculite. All are available from hardware stores or garden centres. Moisten the mix if necessary. Fill your seedling pots with this homemade mix, add seeds, and sprinkle a thin layer over your seeds if they need to be covered.
Getting started with your winter vegetables
Make space by taking out summer crops that are finished or almost finished. If you don’t want to sacrifice the last tomatoes, pull out the plants and hang them upside down (roots and all) in a cool place for the fruit to ripen.
Wash seedling trays and pots with liquid soap and hot water, and stock up with germinating mix.
Quick soil checks
How compact is your soil?
Take a large, empty instant-coffee tin and remove the bottom. Push or dig it into the soil, leaving about 9cm of it above the soil. Pour in some water, marking the water height. Time how long it takes for the water to drain away. Repeat this several times until the rate of absorption slows and the times become consistent. Anything slower than 1.5 – 3cm per hour is an indication of compacted soil at the level of the roots, which is where they need water and air.
How workable is the soil?
If you dig up clods or clumps of soil, workability is low. The less clumpy the soil is, the easier it is for water to reach the roots. Break down clumps and add more organic material.
Is there life below ground?
Dig out the soil to a depth of 15 – 30cm and count the number of earthworms. The absence of earthworms means that the soil does not contain enough organic matter to sustain them. Earthworms are important for soil quality: they improve drainage, bind the soil together, and make nutrients available to the plants.
Don’t forget to renew the nutrients in the soil by adding compost, or spreading a thin layer of fertilis (worm castings) over the surface and working it into the top few centimetres. Organic fertilisers like Vita Grow 2:3:2 (16) can also be added. They don’t contain carrier salts so will not burn the plants.
5 Easiest Winter Vegetables to Grow
This is the last month to plant broccoli. Make sure the plants receive full sun during winter and are watered regularly so that they do not wilt. They need fertile soil so enrich with compost before planting. When planting out seedlings or transplanting, lightly fertilise with 6:3:4 but don’t put the fertiliser in the planting hole or against the stem or it will burn. Two weeks after planting, feed with a nitrogen-rich fertiliser like Margaret Roberts organic supercharger, and again after four weeks.
Winter varieties like ‘Cape Spitz’, ‘Brunswick’, ‘Drumhead’, ‘Glory of Enkhuizen’, and hybrids ‘Conquistador’ and ‘Hercules’ as well as Chinese cabbage can be sown from February to May. Plants need full sun, fertile soil that drains well, and space to grow, at least 1m² per plant. Prevent aphids and bagrada bug by spraying preventively with an organic insecticide once a week. The green peach aphid is a carrier for beet-yellowing virus, also known as brassica stunting disorder, which prevents heads forming and turns the leaves red or yellow. Planting too close together, getting not enough sun or not enough water may also affect the formation of heads. Use bird netting to protect young seedlings.
‘Cape Market’ and ‘Scarlet Nantes’ are cool-season varieties and are best sown now. The specific requirement of carrots is deep, loose soil that drains well. Do not enrich the soil before planting. If the garden has heavy or compact soil, rather grow baby carrot varieties in containers. Mixing the seed with mealie meal helps distribute it more evenly. Cover the seed with a thin layer of sand and firm down. Because the sowing depth is so shallow, seed dries out easily. Water once a day while the seed is still germinating. Carrots must be thinned out or the yield will be poor. Start early, when 2 – 3 leaves have developed, because it is harder to thin out later when the roots become intertwined. The final spacing should be 3 – 5cm apart. Two or so weeks before harvest, water the carrots with Epsom salts dissolved in water. This gives the carrots a deeper colour and sweeter taste.
Kale is less troubled by pests than other brassicas, is disease resistant and tolerates cold (which gives the leaves a sweeter taste). Plant in full sun or semi-shade, in fertile soil that is slightly acidic. Feed monthly with a nitrogen-rich fertiliser. Plants grow up to 1m, and the leaves are picked from the bottom upwards, always leaving the top four leaves as the growing crown. Cook kale like spinach or mix it with spinach leaves. Lettuce (loose-leaf or crisp-head) If you’ve had to nurse lettuce through summer, take heart – this is now the best time to grow it. In autumn and winter grow lettuce in full sun. Plant in fertile, slightly acidic soil that drains well and is enriched with compost and bonemeal. Sow crisphead lettuce first because it takes longer to mature than loose-leaf lettuce. Space plants 30cm apart for ample air circulation. With this kind of spacing they are less likely to fall prey to fungal diseases. Keep the soil consistently moist, as drought stressed lettuce develops a bitter taste. Fertilise monthly, preferably with a liquid organic feed. For a better taste and colour, water the lettuce with added Epsom salts (1 tablespoon to 5 litres of water).