How to grow rape, covo and kale

Make a small, fine seedbed in a sheltered, well-drained spot with light shade. Rake the soil to a fine crumb, like flour, so the dust-fine seed sits snug against it, and mix in a little well-rotted compost.

Draw shallow drills (little furrows) across the bed, 10–15 cm apart — a bit under a hand-span (a hand-span, thumb-tip to little-finger, is about 20 cm).

Sow the seed thinly along each drill — a pinch trickled slowly, not a heavy line — then barely cover it, only 1–2 cm deep, about half a finger-joint. The seed is dust-fine; sown deep it rots in the ground before it can reach the light.

Water gently with a fine rose, or a leafy branch dipped in water, so you don't wash the seed out of the drills. Keep the bed moist but never soaked, watering in the morning; the seedlings should show in about a week.

If barely any seedlings are up after 10 days, sow a fresh bed at once rather than wait on a bad one — you still have time before transplant.

Once the seedlings open their first proper leaves, thin any crowded patches so each stands about a finger-width apart. Crowded seedlings grow thin, tall and weak.

Aim to transplant at 3–5 true leaves (the proper leaves that come after the first pair), up to a hand-span (about 20 cm) tall — roughly 4 weeks from sowing.

First run a germination test so you don't cook weak seed: sprout 50–100 seeds on a damp cloth for about a week and count how many grow. Do this the week before you mean to treat and sow.

Only treat seed that sprouts well. If few of them grow, the seed is weak → buy fresh seed rather than treat it, because hot water sets weak seed back even further.

Warm clean water to exactly 50 °C — hot to the hand but not scalding. You need a thermometer: hotter than 50 °C cooks the seed dead; cooler doesn't kill the germ. Keep a kettle nearby to top up and hold the heat.

Tie the seed loosely in a thin cloth and hold it in the water for 20–30 minutes, swirling it now and then so every seed stays evenly warm.

Lift it out, spread the seed to dry in the shade, then sow within a day or two.

Never treat seed that came already coated or coloured (that means it is treated) from the shop — you'd wash off the protection, and the seed can be harmed.

In the last week before you lift them, cut back on watering — water less often, and let the bed dry a little between waterings.

Open up any shade and let the seedlings feel more sun and wind, so their leaves toughen and darken.

Keep this up for about a week. Hardened seedlings look sturdier and a little darker, not soft and pale.

Water the bed well the evening before you lift, so the roots come up in a ball of moist soil and hardly feel the move.

Only lime if your soil is sour. A soil test tells you for sure; so does a memory of past crops that stayed yellow and stunted even when you fed them. Your recommendation gives the amount for your field.

Spread it evenly over the nursery bed and the field, like sprinkling flour by hand — patches of lime give you patches of good and bad plants.

Work it into the topsoil with a hoe. Lime only sweetens the soil it is mixed into; left lying on top it does almost nothing.

Do it as early as you can — weeks to two months before transplanting — because lime is slow to act. Where clubroot is a known problem, lime harder, to a sweeter soil, and your recommendation will say so.

Use only well-rotted manure or compost — dark, crumbly, and without a strong smell. Fresh, strawy manure still needs time to rot down.

Spread it thickly and evenly over the beds — far more than a grain crop needs. Aim for about 2–4 kg over every square metre (one pace each way — a pace is about one metre). As a picture, one loaded wheelbarrow (about 50 kg of rotted manure) covers roughly a 4-pace by 4-pace patch.

Work it into the topsoil in the 1–2 weeks before you transplant, so it settles in and is ready when the roots arrive.

On heavy or wet soils, make raised beds as you dig it in — these greens rot in soggy ground.

Buy stocky, dark-green seedlings at 3–5 true leaves, up to a hand-span tall — not tall, thin or pale ones.

Check each one: no yellow, V-shaped patches with blackened veins (black rot), no webbed-over growing centres, and no wilting. Reject the whole batch if many look sick.

Buy from a nursery raising seedlings on clean, fresh media, away from any old cabbage-family patch — that's how black rot and clubroot travel.

Transplant them within a day or two of buying, keeping them shaded and watered until you do.

Transplant in the cool of evening, when the seedlings have 3–5 true leaves. Water the nursery first, then lift each seedling with a ball of soil so the roots barely break.

Set the plants about 45 cm apart each way — just over two hand-spans (a hand-span is about 20 cm). Go as close as 30 cm for more but smaller leaves, or up to 60 cm between rows for bigger plants. Plant to the same depth they grew in the nursery, firm the soil around each, and never bury the growing centre.

Place the basal compound fertiliser plus boron in each station as your recommendation directs, mixed into the soil just below and to the side of the roots — not touching them, or it burns. The compound gives the young plant phosphorus, potassium and sulfur; boron is a trace food (needed in tiny amounts) these greens must have, or their stems turn hollow and brown inside.

Water in well right after planting, so the soil closes around the roots and each seedling stands up firm.

On sour (acid) soils, spray a molybdenum feed over the leaves about a week after transplanting — molybdenum is another trace food, the one that lets the plant use its nitrogen. Your recommendation will tell you if you need it.

Twice a week, walk a large 'W' across the field so you cover the corners and the middle, not just the edge by the path. Stop often and look closely at the young plants.

Cabbage webworm (the worst one here): look for the tiny growing centre webbed over with silk, with small caterpillars boring into the heart. A hit plant stops growing or dies. Squash them; on a bad run, spray as your control guide directs.

Cutworms: look for seedlings cut clean off at ground level (worst first thing in the morning). Scratch the soil around the cut stump to find the fat, grey, curled-up caterpillar, and kill it.

Flea beetles: look for many tiny round 'shot-holes' peppering the leaves, and little dark beetles that jump away when you touch the plant — worst in hot, dry spells on young seedlings.

Start turning over a few leaf undersides for the caterpillar you'll fight all season — small green diamondback-moth grubs (no longer than a fingernail) that wriggle and drop on a silk thread when disturbed. Much more on these once the leaf frame builds.

If you find gaps or dead seedlings, fill them in the first week or two from your spare nursery seedlings, while replacements can still catch up. → Found a gap later than that? Leave it: a late seedling only shades and stunts, so save that space for your next planting.

Keep the topsoil moist but not waterlogged — water every 2–3 days, and more often in heat or on sandy soil that dries fast.

Water in the cool of morning or evening, so less is lost to the sun and the leaves dry off before night.

Check with a finger: water when the top few centimetres are dry. These shallow-rooted greens can't reach down for deep water.

Feed 2–3 weeks after transplanting, once the plants are established and growing away.

Use the recommended nitrogen — CAN or AN (calcium ammonium nitrate or ammonium nitrate). If you use CAN, it also brings calcium, which these greens like; plain AN does not. Your recommendation gives the amount.

Top-dress it — that means sprinkle a band of the fertiliser a hand-span (about 20 cm) to the side of the plants, not on top of them — on moist soil, after a weeding or a light rain.

Cover it or water it in so it doesn't gas off into the air and go to waste, and keep the grains off wet leaves, where they stick and scorch little holes.

Weed 2–4 weeks after transplanting, before the weeds grow bigger than the crop.

Hoe shallowly. These greens root shallow, and deep hoeing near the plants cuts the feeder roots the leaves live on.

Pull the weeds close to the stems by hand, so you don't wound the plants.

Lay a mulch — dry grass, leaves, or the pulled weeds — between the plants. It holds moisture, keeps the soil cool for the shallow roots, and slows the next flush of weeds.

Twice a week, walk the 'W' and turn the leaves over — most pests hide on the underside.

Diamondback moth (DBM): look for small green caterpillars no longer than a fingernail that wriggle and drop on a silk thread when you touch them, and pale 'windows' — patches where they've eaten the underside of the leaf but left the top skin, so light shines through. On a leaf crop, act at the first few — about one grub on every two or three plants.

Cabbage aphid: look for grey-green, powdery (waxy) clusters packed on the growing centre and leaf undersides, with sticky honeydew (the sugar they excrete) and black sooty mould growing on it. Rub out small colonies by hand.

Black rot (a bacterial disease): look for yellow, V-shaped patches biting in from the leaf edge, with the veins inside turning black. Pull out and remove any hit plant, and never work the crop while the leaves are wet — wet hands and tools carry it from plant to plant.

To spray DBM, use Bt (short for Bacillus thuringiensis, a natural germ that sickens only caterpillars and is safe on food you'll eat), sprayed in the late afternoon — strong sun breaks Bt down, and the caterpillars feed at dusk. Wet the leaf undersides, where they hide.

Rotate — change the spray family — every generation. DBM builds resistance fast, so the same spray twice running soon stops working. When you spray, cover your skin, nose and eyes, spray in the cool with the wind behind you, keep it off food, and wash well after.

Keep the soil evenly moist — water every 3–4 days, and more often in heat or on sandy soil.

Water in the cool of morning or evening, at the base of the plants.

Check with a finger and water when the top few centimetres are dry — the shallow roots can't wait for deep water.

Start picking when the lower leaves reach full size — about 4 weeks after transplanting — then come back every 1–2 weeks.

Take the oldest, outer, full-size leaves first, snapping or cutting them off cleanly at the base of the stalk.

Always leave the growing centre and the top few young leaves — at least 4–6 leaves on each plant — so it can regrow. A picked plant should look like a little palm tree: a tuft of leaves on top of a bare lower stem.

Pick in the cool of the morning, when the leaves are crisp and full of water, and get them out of the sun straight away.

Feed nitrogen after each pick (the next task) — that's what powers the regrowth for your next harvest.

Take off any yellow, tough or pest-eaten lower leaves at the same time, to keep each plant clean and tidy.

Feed straight after each pick, every 1–2 weeks, using the recommended CAN or AN nitrogen — if you use CAN it also brings the calcium these greens like, while plain AN does not. Your recommendation gives the amount.

Top-dress it — a band of grains a hand-span (about 20 cm) to the side of the plants, never on the growing centre.

Apply on moist soil and water it in, so it reaches the roots instead of gassing off into the air.

Keep the grains off wet leaves (they scorch), and don't overdo it — too much nitrogen at once makes soft leaves that pests and rot love.

Twice a week, walk the 'W' and turn the leaves — check the undersides and the growing centre.

DBM: small green caterpillars that drop on a silk thread, plus pale 'window' patches on the leaves. Under pressure, spray Bt (the caterpillar-only germ) every 5–7 days, in the late afternoon — sun destroys Bt, and the grubs feed at dusk.

Cabbage aphid: grey, waxy clusters on the tips and undersides. Wash or rub off small lots; spray if they build up.

Downy mildew: look for pale-yellow patches on top of the leaf with a greyish-purple furry mould underneath, in cool, damp weather. Open the plants up for airflow, avoid wetting the leaves late in the day, and remove the worst-hit leaves.

Rotate your spray family every generation — never the same one twice running, or DBM stops feeling it.

When you spray any chemical: cover skin, nose and eyes, spray in the cool with the wind behind you, keep it off food, and wash well after.

Keep the soil evenly moist — water every 3–4 days, and more often in heat.

Water at the base of the plants in the cool of the day, not overhead in the evening.

Never let the crop wilt hard between picks — thirst makes tough leaves and can trigger bolting (running to flower).

Twice a week, keep walking the 'W', turning leaves for DBM (small green grubs that drop on a silk thread; pale 'window' patches) and cabbage aphids (grey, waxy clusters). Spray Bt in the late afternoon, rotating the spray family each generation.

Clubroot: if plants wilt in the heat, then yellow and stunt for no clear reason, pull one up. Swollen, distorted roots like clubs or knobbly fingers mean clubroot, a soil disease worst in sour, wet ground. Remove the hit plants and don't spread their soil around the field.

Bolting: watch for a stalk shooting up from the centre with flower buds — after this the leaves turn tough and bitter. This ends the plant, so clear it and use the space.

Keep respecting the pre-harvest interval on every spray — you're still picking and eating these leaves.

Lime only if your soil is sour, or clubroot is a known problem — a soil test, or stunted, wilting, club-rooted plants, tells you.

Spread it evenly and work it into the topsoil around the crop. Where clubroot is the reason, lime harder, to a sweeter soil (your recommendation gives the amount).

Keep the ground well drained — clubroot thrives in wet, sour soil, so raised beds and good drainage help as much as the lime does.

Get the leaves out of the sun the moment you pick — into shade, a cool room, or under a damp cloth. Picking in the cool of morning helps most of all.

Cool them down as much as you can — a dip in clean cool water, or a cool, shaded, damp store. Cold, damp air keeps them crisp; warmth yellows them fast.

If the leaves are soiled, wash them in clean water and let the surface dry a little before packing.

Bunch 8–12 leaves together and pack them loose in crates or baskets — do not press them down, because bruised, crushed leaves are the first to rot.

Keep the bunches away from ripening fruit like bananas and tomatoes — the ripening gas (ethylene) they give off yellows the leaves.