How to grow African eggplant

Choose your type first, because it changes everything after: a fruit type (Gilo or Kumba groups) for round fruit, or a leaf type (Shum / nakati) for leafy greens. Buy clean seed of that type from a trusted source.

Make a raised nursery bed of fine, clean, well-drained soil, or fill trays — somewhere that will never flood. Water it first so it is damp, not wet.

Sow the seed shallow — barely cover it, no deeper than about 1 cm (a fingernail deep). Sow thinly in little rows; crowded seedlings grow thin and weak and fall to rot.

Keep the bed evenly moist, never waterlogged. Give it shade in fierce heat and good airflow, so the leaves dry off each day.

When seedlings crowd each other, thin them (pull out the weakest) or prick them out (lift and replant them wider apart) to give each one room. Raise them for about 30-35 days, until they have 5-7 leaves and stand a hand-span tall (15-20 cm).

In the last week before moving them, harden them off — toughen them up — by giving a little less water and a little more sun each day, so they don't wilt when they hit the field.

Well before you transplant — around the time you start the nursery, about 3-6 weeks ahead — decide exactly where the crop will go, not just that you'll grow it.

Pick a plot that has not grown tomato, potato, pepper, eggplant or African eggplant for at least the last 2-3 seasons. The longer the break, the safer you are.

Choose to follow cereals (maize, sorghum, millet) or legumes (beans, groundnuts) instead — they don't carry this wilt, and they leave the soil in good heart for a hungry crop.

Avoid low, wet ground where water sits after rain: bacterial wilt spreads in water and wet soil, so a soggy plot lets it race from plant to plant.

Clear weeds and old crop trash, then dig or plough deep — as deep as you can work it — so roots reach down and rain soaks away instead of pooling.

Work in plenty of well-rotted manure or compost — about a wheelbarrow every few strides across the plot. Well-rotted means dark and crumbly with no strong smell; fresh manure burns young roots.

Manure and wood ash also bring potassium (K), which this crop is hungry for — it builds firm, well-coloured, better-tasting fruit.

On flat or low ground, make raised beds or ridges so water drains away fast. Standing water both rots the roots and spreads bacterial wilt.

Mark out your planting positions at the final spacing — about a stride (90 cm) between rows and a stride (90 cm) between plants for fruit types (set them closer for leaf/Shum crops, which you cut young).

Decide your type first — a fruit type (Gilo/Kumba) or the leaf type (Shum/nakati) — and buy seedlings raised from clean seed of that group.

Pick stocky seedlings, 5-7 leaves and about a hand-span tall (15-20 cm), with a thick stem — not tall, thin or pot-bound ones.

Check each one for wilting, yellowing or spotted leaves and reject the whole batch if many look sick — a bought-in wilt problem can never be cured once it's in your field.

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

Transplant your hardened, 30-35-day seedlings (5-7 leaves, a hand-span tall). Water the nursery an hour before lifting, so soil clings to the roots and they come up with a ball of earth.

Work in the cool of the day — early morning, late afternoon, or an overcast day — never in the hot midday sun, which wilts fresh transplants.

Set plants at the marked spacing: about a stride (90 cm) between rows and a stride (90 cm) between plants for fruit types; closer for leaf (Shum) crops.

Plant each seedling to the same depth it sat at in the nursery, firm the soil gently around the roots so there are no air pockets, and water it in at once.

Never plant where tomato, potato, pepper or eggplant grew recently — check the plot's history one last time before you set a single seedling.

From about 2 days after transplanting, walk the whole crop twice a week (every 3-4 days), looking at plants in all corners and the middle — not just the row by the path.

Cutworms: look for young plants cut clean off at ground level, worst overnight. Scratch the soil around a freshly cut plant in the morning to find the fat, greasy, grey-brown caterpillar curled into a 'C'; squash it.

Flea beetles: look for leaves peppered with tiny round 'shot-holes' (pinholes). Tap a plant and the little dark beetles jump away like fleas. A heavy attack in hot, dry weather can stunt small plants.

Bacterial wilt: look for a plant that wilts and collapses while still green — no yellowing first. To be sure, cut a wilted stem near the base and hang the cut end in a glass of clear water: a milky-white thread streaming down from the cut confirms wilt.

Pull and destroy any wilt-struck plant at once (see the wilt guide), and write down what you saw and where, so you can tell a spreading problem from a one-off.

About 1-2 weeks after transplanting, walk the rows and count how many seedlings are alive and standing against how many you set out.

Work out the share that took — for example, 90 living plants from 100 set out = 90%.

90% or more → a good take, carry on.

Below 90% → gap-fill now: lift a healthy spare seedling with a ball of soil and replant it into each gap in the cool of the day, then water it in. Do it in the next few days, while replacements can still catch the rest.

If plants keep dying even after replanting — and they wilt green without yellowing first — suspect bacterial wilt, not thirst. Stop replanting into that patch (do the 'ooze in water' test to confirm); fresh seedlings there will only die too.

Start feeding from about 2 weeks after transplanting, once the plants are growing away, and keep feeding through the season — a little after each burst of picking or cutting.

Band the nitrogen (spread it in a line) a hand-span (about 20 cm) to the side of the plants, not on the stems, then cover it or water it in so it doesn't gas off and go to waste.

Use roughly a bottle-cap per plant as a rough guide, but follow the exact amount your recommendation gives for your field and soil.

Feed only when the soil is moist (after watering or light rain) — nitrogen on dry soil just sits there doing nothing.

Weed in the first few weeks after transplanting, before the weeds get bigger than the crop, and keep the field clean as the canopy fills in.

Hoe shallowly between and around the plants — deep hoeing close in cuts the crop's own roots.

In dry areas, leave the pulled weeds lying between the rows as a mulch to hold moisture and slow the next flush.

For vigorous fruit types, push a stake in beside each plant while it is still small and tie the main stem to it loosely, so it can carry a heavy fruit load without falling over.

This is only for leaf (Shum) types: begin cutting from about 3-5 weeks after transplanting, once the plants are leafy and well rooted.

Pluck or cut the tender young leaves and shoot tips, taking the soft top growth and leaving enough lower leaves for the plant to keep feeding itself.

Come back every 1-2 weeks for the next cut — regular picking pushes out fresh, tender regrowth.

Feed a little after each cut (see the nitrogen task) so the plant has the food to grow the next flush of leaves.

Leaf is highly perishable — cut in the cool, keep it shaded and moist, and sell or eat it the same day.

Walk the crop twice a week (every 3-4 days), checking plants right across the field, not just the edge.

Fruit-and-shoot borer: look for a growing tip that suddenly wilts and droops — a 'dead-heart' (the shoot has died from the inside). Near the wilted part you'll find a small hole plugged with droppings where the caterpillar bored in.

Cut off every wilted, bored shoot and destroy it — burn it or bury it deep. Don't just drop it on the ground, or the caterpillar inside lives on to breed again.

Aphids: look on shoot tips and the undersides of soft leaves for clusters of tiny green or black insects, curled leaves, and sticky, shiny 'honeydew' (often with ants running about).

Whitefly: shake a plant — if a cloud of tiny white flies rises from under the leaves, you have whitefly. Both pests leave sticky leaves and a sooty black mould.

Write down what you find. If bored shoots or sap-suckers are spreading, act — open the matching pest guide before deciding whether to spray.

From about 6-8 weeks after transplanting, once flowers and fruit are setting, keep the soil steadily moist — water every 5-7 days, more often in heat or on sandy soil that dries fast.

Check by pushing a finger in: water when the top finger-joint of soil (the first 3-5 cm) is dry, before the plant ever wilts.

Water evenly — a sudden swing from bone-dry to soaked can crack fruit and drop flowers as badly as drought does.

Keep water off the leaves where you can, and water in the cool, to avoid spreading leaf and soil disease in the wet.

Every few days (every 3-5 days), walk the crop looking for wilted, drooping shoot tips and fruit with a hole plugged by droppings or a soft, rotting patch.

Cut off each bored shoot below the damage, and pick off every bored fruit, however small.

Destroy them — burn them, bury them deep, or feed them to livestock. Never leave them lying in the field, or the caterpillars crawl out, turn into moths and come straight back.

Do this at the same time as scouting and picking, so it becomes one steady habit rather than a big clean-up when it's too late.

Twice a week (every 3-4 days), check growing tips and fruit of every size across the whole crop.

On shoots, look for the wilting 'dead-heart' tip; on fruit, look for a small entry hole plugged with droppings, and cut one suspect fruit open to find the tunnel and caterpillar inside.

Remove and destroy every bored shoot and fruit you find, the same as in the removal task — scouting and destroying go hand in hand.

Note how many plants show fresh boring. If it is climbing fast and hand-removal isn't holding it, open the borer guide to choose a control — and time any spray for the egg and young-caterpillar stage, since grown caterpillars are hidden safe inside.

Start picking from about 8-9 weeks after transplanting, then come back every 3-5 days — this is a crop you harvest little and often, not all at once.

Pick a fruit when it is at full size for its type, its skin firm and glossy, and the flesh springs back to a gentle press. Pick it before the skin dulls and the seeds inside harden — a young fruit's natural bitterness is fine and expected, so don't wait for it to 'sweeten'.

Cut the fruit off with a short stalk rather than tugging — pulling tears the branch and bruises the fruit.

For leaf (Shum) types, keep cutting the tender leaves and shoot tips the same way every 1-2 weeks.

Handle everything gently and keep the harvest cool and shaded — fruit bruises easily, and leaf must be sold or eaten the same day.

If a fruit fails the test — skin gone dull, flesh no longer springy, seeds hard and browning, and the taste turned harshly bitter — it is over-ripe: pick it off and discard it or feed it out anyway, so the plant puts its strength into new fruit.

Through the harvest, feed every 2-3 weeks — a light top-dress of nitrogen spread around the plants, at the amount your recommendation gives.

Apply it on moist soil and water it in; a small feed after each big picking round keeps the plant flushing.

Keep the water coming too — a well-fed plant with dry soil still drops its fruit.

Well-rotted manure or wood ash worked in alongside adds potassium (K), which this crop is hungry for and which firms up the fruit and improves its taste.

Once picking is over (from maturity onwards), pull out the old plants and remove all the crop residue from the field.

Destroy the residue — burn it or bury it — so any borer caterpillars and pupae inside the stems and leftover fruit die instead of breeding the next generation.

Rotate the plot to a non-tomato-family crop — a cereal (maize, sorghum) or a legume (beans, groundnuts) — and keep tomato, potato, pepper and eggplant off it for at least 2-3 seasons.

Handle the last of the fruit gently and keep it cool and shaded — it bruises easily; any leaf is highly perishable and must be sold the same day.