How to grow robusta coffee

Understand what a clone is: a cutting grown from one chosen mother tree, so all the young trees are identical copies of that single known-good tree. Clones beat seed here because they come out uniform and you can pick wilt-resistant types.

Take single-node cuttings from healthy, wilt-free mother trees: cut short pieces of young stem, each with one node (the knuckle on the stem where a leaf-pair grows) and one pair of leaves. Trim each leaf back by half so the cutting loses less water.

Set the cuttings in a shaded, damp rooting bed, or in poly-sleeves (small planting bags) of loose, clean soil. Keep them humid under a low frame covered with clear plastic, out of direct sun — roots form over a few weeks.

If you raise seedlings from seed instead, take seed from several different healthy mother trees (never just one), sow in a shaded nursery bed, then prick the young seedlings out into poly-sleeves.

Grow the young trees on in the shade and water regularly. Before planting out, harden them off — slowly cut back the shade and the watering over a couple of weeks so they toughen up. They are ready at about knee-height (about 45 cm) with several leaf-pairs — roughly 6-10 months in the nursery.

If the cuttings blacken and rot, or very few root: the wood was stressed, or the bed too wet or too sunny. Take fresh single-node cuttings from healthy shoots, give more shade, and keep them humid but never soaking.

Know the rule: Robusta is self-incompatible — a flower will not set a berry with pollen from its own tree (or its clone-mates, which are identical copies of it). It needs pollen from a genetically different tree.

Choose at least 3-4 different compatible types (clones or seedling lines). Your nursery or dealer can name types that are known to go together.

Make sure they flower at the same time — pollen only helps if the neighbour is in flower when this tree is. Ask for types with overlapping flowering.

Plan to mix the types across the field (alternate them down the rows) so every tree has a different-type partner within bee-flying distance.

In the 2 months before you plant out, line up enough plants of each type for your whole field.

If you can only get one type: expect very few berries. Get at least one more different, same-flowering type before you plant — even a handful of seedlings — rather than plant a single clone alone.

Pick a warm, low site (0-800 m). Robusta grows best at 22-28 degrees C and is harmed by cold — it can be killed near 5 degrees C — so avoid frost-prone hollows.

Choose deep, well-drained loam (sandy loam, loam or clay loam). Avoid any spot where water sits after rain — coffee roots rot in waterlogged ground.

Coffee likes slightly sour soil (pH 5.0-6.5 is best). It survives from 4.0 to 8.0 but grows poorly at the extremes; add lime only if a soil test shows it is very sour.

In the 2 months before planting, clear the land and dig planting holes 2.5-3 m — about three strides — apart each way. Dig each hole about knee-deep (about 45 cm) and just as wide, and mix the topsoil back with well-rotted manure or compost.

On slopes, plant across the slope and dig the ground well, so the heavy rains (this is a wet crop — 1200-3000 mm a year) soak in instead of washing the soil away.

Where it is very hot and exposed, plan light shade (a few scattered shade trees) — young coffee does better with a little shade than in full, blazing sun.

Plant at the start of the rains (the first week or two) so the young trees settle in with steady moisture.

Mix several different compatible types across the field — alternate the types along each row so every tree has a different-type neighbour within bee range. (A tree can't pollinate itself.)

Space the trees 2.5-3 m — about three strides — each way, one tree per hole (about 1350 trees fill a hectare).

Plant into the prepared holes at the same depth the tree grew in the nursery — don't bury the stem. Firm the soil gently around the roots and water in well.

Mulch heavily around each tree — a thick ring of dry grass or leaves to hold moisture and smother weeds — but keep the mulch a hand-span (about 20 cm) clear of the stem so the bark doesn't rot.

Give a little young-tree fertiliser after planting (see the young-tree NPK task), spread in a ring and kept off the stem.

If the rains fail and young trees wilt: water by bucket each week and thicken the mulch; replace any that die, keeping the same mix of types.

From about a month after planting, walk the whole plot once a month (every 4-5 weeks).

Coffee wilt: look for a whole tree — or one side of it — suddenly wilting and yellowing, with the dead leaves hanging on instead of dropping. Peel a little bark: dark brown or blue-black streaks in the wood (the tree's water pipes) confirm it. Mark that tree and go straight to the wilt-sanitation task.

Berry borer (once the trees carry cherries): look for a tiny round hole at the crown (blossom) end of green or ripe cherries — the end away from the stalk — sometimes with fine 'sawdust'. Hang funnel traps baited with a methanol-and-ethanol mix (both are types of alcohol) to catch the flying beetles.

Leaf spot (brown-eye): brown spots on the leaves and berries with a pale grey centre and a yellow ring — like an eye.

Root-knot nematode (a tiny soil worm): if young trees stay stunted and yellow for no clear reason, dig gently beside one and look for knobbly swellings on the roots.

Note what you saw and where, so you can act on the matching task.

Start feeding from about 3 months after planting (once the tree has taken hold), and repeat every 3-4 months through the first year.

Use a balanced compound (roughly equal parts N, P and K). Your recommendation gives the exact amount — as a rough guide, about a small handful (a matchbox-full) per young tree.

Spread it in a ring around the tree, out at the drip line — the circle on the ground under the outer leaves, where rain drips off the canopy; that's where the hungry feeding roots are — not against the stem.

Feed onto moist soil (after rain or watering) and cover it lightly with soil or mulch so it isn't wasted.

Safety: wash your hands afterwards; keep fertiliser off wet leaves, out of streams and drinking water, and away from food and children.

From about 6 months after planting, walk the whole plot once a month.

Coffee wilt: a whole tree, or one branch or one side, wilts and yellows while the dead leaves stay hanging on; under the bark the wood shows dark brown or blue-black streaks. Treat any such tree as wilt — mark it and go straight to wilt-sanitation.

Brown-eye / leaf spot: brown spots on the leaves with a pale grey centre and a yellow ring (like an eye), worst on hungry, unshaded or waterlogged trees. Improve feeding, shade and drainage, and rake up the worst fallen leaves.

Check that the new growth is healthy and green — pale, hungry leaves mean it's time to feed.

The moment a tree shows wilt (whole-tree or one-sided wilting plus dark streaks in the wood), act — don't wait.

Uproot the whole tree, roots and all, and burn it on the spot. Don't drag it across the plot (that scatters the spores), and never keep it as firewood or mulch.

Flame or disinfect every tool (panga, hoe) you used — and your hands — before you touch a healthy tree.

Dig out and burn as much of the root as you can, then leave that hole empty — fallow, meaning unplanted — for 6-12 months. Don't replant coffee in the same spot straight away.

When you do replant, use only wilt-resistant clones and clean nursery stock.

If it keeps spreading: widen the gap — remove neighbouring trees as soon as they start wilting too, keep every tool flamed, and stop moving any coffee material around the plot.

Formative training (young trees, from about 6 months): keep 2-3 strong upright stems per tree and rub or cut off the rest, so the tree grows an open frame of a few main stems. (Some growers bend or cap the single stem to force these stems up.)

Each year, cut out dead, weak, crossing and diseased branches and any low suckers (side shoots low on the trunk), to let light and air into the tree.

Change-of-cycle (stumping) on older trees: when a main stem gets old and bears poorly, cut it right back near the base to force fresh young shoots. Bring on a few of these new shoots and, over several cycles, renew the whole tree.

Do the hard cutting after harvest / at the start of the wet season, so the fresh shoots grow away strongly.

Burn or carry off the prunings — especially any dry old berries on them — to deny the berry borer a home.

After the first rains break a dry spell, the trees flower — often heavily and all together, over roughly the first 3 weeks of the flowering season.

Check that your different types are flowering at the same time. This overlap is what lets them pollinate each other.

Protect the bees — they do the pollinating for free. Do not spray any insecticide (bug-killer) on open flowers; if a pest must be controlled, wait until flowering is over.

Keep some flowering plants or hedges around the plot so bees stay nearby.

Keep the trees watered through flowering — thirsty trees drop their flowers before they can set.

If one type flowers well but its partners don't (or set is poor): note which types don't line up, and at the next planting fill in with types that flower together. This year, just make sure nothing kills the bees.

Through flowering and early berry set, check the trees twice a week (every 5-7 days).

Antestia: a brown, shield-shaped bug with pale markings on flowers, shoots and green berries; it gives off a strong smell when disturbed. Also watch for capsid bugs (soft green or brown bugs) causing dark, sunken spots on shoots and berries.

Tap a branch over a cloth or open lid and count the bugs that fall; check several trees right across the whole plot.

Only if numbers pass the threshold (a few bugs per tree — follow your local advice), spot-spray just the affected trees with a recommended insecticide — after flowering, never on open flowers full of bees.

Spray safety: cover your skin, eyes and nose; spray in the cool of the day with the wind at your back; keep off food and water; respect the pre-harvest interval (the number of days you must wait after spraying before you may pick, so no poison is left on the cherries); and wash yourself and the sprayer afterwards.

From flowering right through berry fill, walk the plot weekly (every 7-10 days).

Berry borer: look for a tiny round hole at the crown (blossom) end of green and ripening cherries — the end away from the stalk — sometimes with fine 'sawdust' at the hole. Split a few suspect cherries: you may find the tiny black beetle and its grubs in the seed.

Hang funnel traps baited with a methanol-and-ethanol (alcohol) mix among the trees; rising catches warn you the beetles are flying and it's time to tighten sanitation.

Coffee leaf rust: also watch for orange-yellow powdery patches on the underside of the leaves and early leaf drop. Robusta shrugs rust off better than Arabica, but note it and keep the trees well-fed and open.

Keep a note of trap catches and holed cherries so you can act on the sanitation task.

Every month or so through the season, strip the trees of any leftover, over-ripe, dried ('mummified') and holed cherries.

Pick up the fallen cherries from the ground under the trees too — the beetle breeds in these.

Destroy what you collect: burn it, bury it deep, or soak it in hot or soapy water — don't just heap it at the plot edge.

Do a thorough clean-up strip right after the main harvest, so no cherries carry the borer into next season.

If you use a biocontrol — Beauveria, a natural fungus that infects and kills the beetle — apply it as advised, alongside sanitation, not instead of it.

Feed potassium during berry fill — from flowering through the main filling months, every 2-3 months.

Use a potassium fertiliser such as muriate of potash (MOP). Your recommendation gives the exact amount — as a guide, spread about a handful in a ring around each tree.

Spread it in a ring at the drip line (the edge of the leaf canopy, where the feeding roots are), onto moist soil, and cover it lightly with soil or mulch.

Don't pile it against the stem, and keep it off wet leaves.

Safety: wash your hands afterwards; keep fertiliser out of streams and drinking water and away from food and children.

Start picking at about 9 months after flowering, when the cherries are fully and evenly coloured — deep red (or yellow on yellow types), firm and glossy.

Pick selectively: take only the ripe cherries and leave the green ones to ripen for the next round. Roll each ripe cherry off with your fingers; don't strip the whole branch.

Go round again every 10-14 days as more cherries ripen — several rounds across the season.

On each round, also pick off any dried, over-ripe or holed cherries, keep them separate, and destroy them (berry-borer sanitation) — don't drop them under the tree.

Put the picked cherries in clean bags or baskets and get them to drying the same day (see the sun-dry and hull task).

If cherries are still green or part-coloured, or squash softly when pressed: they're not ready. Leave them and come back in a week or two — stripping a branch of unripe cherries to save a trip costs you weight and price.

Spread the whole ripe cherries in a thin layer on raised drying beds or clean tarpaulins / mats — never on bare ground, which pushes damp and dirt back in.

Turn them several times a day so they dry evenly, and rake them into a heap and cover them at night and whenever rain threatens.

Dry until the cherries are hard and rattle — about 11-12% moisture. A well-dried cherry is hard, the bean loose and rattling inside, and it no longer dents when you press it.

Then hull the dry cherries — crack them open with a pestle-and-mortar or a hand huller to break off the dried skin, pulp and the parchment (the thin papery skin around the bean) and free the clean beans.

Store the hulled beans dry, clean and off the floor in a cool, airy place; winnow out the dust and any broken or black beans first.

If the cherries still feel soft, bendy or leathery, or the bean squashes: they're too wet to store. Keep drying and turning, and don't bag them until they're hard and rattling, or they'll mould.