How to grow cashew

Pick warm, low-lying ground (below about 500 m) that never gets frost. Cashew dies at freezing point — if your nights turn cold and frosty, this is the wrong crop for that spot.

Choose deep, sandy or sandy-loam soil that drains fast. Cashew loves light, poor land, and its deep taproot digs down to find its own water — but it drowns where the soil stays wet.

Walk the land after heavy rain: if water pools and sits, that spot is a red flag — pick somewhere higher. Avoid low spots, hollows and hardpans (a hard buried layer that traps water).

Give each tree full sun and room. A grown cashew is a big, wide, spreading tree — keep it well clear of buildings, shade and other large trees.

Keep pasture, cotton and sweet potato out of the orchard — they feed the mosquito bug (Helopeltis) that will later attack your flowers and young nuts.

Choose land you can watch over and reach easily — you will be visiting these trees for many years, protecting and harvesting them.

Mark your planting spots at the wide spacing a cashew needs: about 8 strides (8 m) apart every way. A full-grown cashew fills all that space — crowded trees shade and starve each other and trap the damp, still air that breeds disease.

At each spot dig a big pit — about three hand-spans wide and three hand-spans deep (60 x 60 cm). Keep the dark, rich topsoil in one heap and the pale, poor subsoil from lower down in a separate heap.

Mix a bucket or two of well-rotted manure or compost into the topsoil heap. Use only well-rotted manure — dark, crumbly, no strong smell — because fresh manure burns and kills young roots.

Refill the pit with that topsoil-and-manure mix, putting the poor subsoil aside or spreading it on top — the young roots should meet the good soil first.

Do this in the month before you plant, so the soil settles and the manure is ready and cool the moment the tree goes in.

Plant at the start of the rains, within about two weeks of your first good, soaking rain — so the young tree gets a full wet season to root down before it ever meets a dry spell.

Buy grafted young trees from a trusted nursery. Look for the graft union — a swollen knuckle low on the stem — and pick sturdy plants with healthy green leaves, not tall, thin or pot-bound ones.

Dig a hole in the middle of your prepared pit. Slip the tree out of its bag without breaking the ball of soil around the roots — hold it by the soil-ball or pot, never by the stem.

Set the tree so the top of the root-ball sits level with the ground, and the graft union (the knuckle) stays well above the soil — never bury it.

Firm the soil around the roots with your hands and heel, then water it in well so the soil settles snugly against the roots with no air pockets.

Push in a stake to hold the young stem straight, and shade it for the first few weeks with grass or palm fronds so the hot sun does not scorch the young leaves.

From planting day, put a guard around every young tree — a ring of thorny branches, a wooden cage, or a fence of stakes — tall and wide enough that goats and cattle cannot reach in and bite the leaves.

Protect the bark at the base from rodents and hares that gnaw young stems. Clear the grass right up against the stem so these pests have nowhere to hide and nest.

Check the guards after wind, storms and passing herds, and mend any gap or gnawed spot at once — a broken guard is an open door.

Keep the guards up for the first one to two years, until the tree is tall and woody and animals can no longer harm it.

From about a month after planting, water each young tree every 1-2 weeks right through the dry season — more often on very hot days and on pure sand that dries out fast.

Give a deep soaking each time — a few buckets poured slowly at the base so the water sinks down to the roots — not a light daily sprinkle that only wets the surface and pulls the roots upward.

Spread a mulch of dry grass or leaves over the soil around the tree — kept a hand-span clear of the stem — to hold the moisture in and keep the ground cool.

Keep this up until the tree is established — growing strongly on its own through the dry season, usually after the first year or two — then you can stop.

From about a month after planting, keep a bare, weed-free ring around each young tree, clearing it every 1-2 months while the weeds are growing.

Make the ring wide — about one-and-a-half times as wide as the leafy top (canopy) of the tree — clearing out past the drip line (the circle on the ground under the outer leaves), because the feeding roots reach at least that far.

Weed by hoeing shallowly or hand-pulling, especially near the stem — the feeding roots run close to the surface, so deep digging cuts them.

Leave the pulled weeds, or a layer of grass mulch, on the ring (but a hand-span clear of the stem) to hold moisture and slow the next flush of weeds.

Once a month, walk to every tree and look it over slowly, from the base upward — young trees are few, so check each one.

At the trunk base and collar (where the stem meets the ground), look for gum oozing out, reddish sawdust-like droppings (frass), and small holes in the bark — signs of the stem borer grub tunnelling inside. Tap the base: a hollow sound is a bad sign.

On the soft new red-brown leaves and shoot tips (the flush), look for dark, sunken black spots and blackened, dying tips — that is the mosquito bug feeding.

Note which trees show damage, and how much, so you can act on those trees (see the pest guides). Flag any borer-hit tree at once — a single grub can kill even a grown tree if it is left.

In the first 1-3 years after planting, train the tree to a single main stem (one leader) — if two stems compete, cut the weaker one out.

Cut off the low side branches and any suckers (shoots from the base) so the clear trunk reaches about knee-to-hip height (60-90 cm) before the branches begin — this lifts the canopy off the ground so you can work under it.

Thin out crowded, crossing and inward-growing branches to leave an open, airy top that light and wind pass through. Open growth dries the leaves fast and starves off powdery mildew and the mosquito bug.

Use a clean, sharp tool, cut close to the branch base (leave no stump), and prune in dry weather so the cuts dry and heal without infection.

Once a month, check every tree, looking closely at the trunk base and collar.

Look for gum oozing out, reddish sawdust-like frass, and small bore holes in the bark — signs the borer grub is tunnelling inside.

Tap the trunk base and listen for a hollow sound, and watch for branches that yellow, wilt or die back for no clear reason.

Flag any affected tree straight away. On an early attack you can hook or dig the grub out of its hole with a stiff wire; cut out and burn any dead or badly infested tree so the beetles cannot breed and spread to your other trees.

Spray in the month before the flower heads (panicles) come out, while the tree is pushing its new flush of leaves.

Mix zinc and boron (for example zinc sulphate and borax) at the rate on the label in clean water, and spray to wet the new leaves and shoot tips until they glisten.

Spray in the cool of morning or evening, out of strong sun, so the leaves take it up without scorching.

This is a helper, not a rescue — in a year you cannot manage it, skip it; but never skip the sulphur mildew sprays that follow, which matter far more.

From the day the flower heads (panicles) first show, check them closely every 5-7 days right through flowering and early nut set.

Look for powdery mildew: white or greyish powder, like flour dusted over the flower heads, shoot tips and young nuts. It is the top killer — and it spreads even in dry weather, on humid nights.

Look for the mosquito bug (Helopeltis): dark, sunken black spots on the flower stalks and young nuts, and blackened flower heads that fail to set. Early in the morning you may catch the slender, long-legged bugs themselves.

If the weather turns wet, look also for anthracnose: dark, sunken spots, some with pink or orange specks in the middle, on shoots and young nuts.

Act on what you find — keep up the sulphur for mildew, and spray for the mosquito bug at the first damage (see the spray tasks and the pest guides). If you already see white powder, you are behind — spray today.

Start at the first flower heads and repeat every 10-14 days through flowering and nut set — always keep a fresh protective coat on the growing flowers.

Dust sulphur (or spray the fungicide your recommendation gives, at the amount it sets) early in the morning when the air is still, so the fine powder settles evenly over the flower heads and young nuts.

Remember sulphur is a protectant, not a cure — it shields healthy flowers but cannot clear mildew already dug in — so keep the cover going and never let it lapse during the flowering weeks.

You may skip a round in a fully dry, mildew-free spell, but check again in 5-7 days — humid nights bring it back fast.

If the flowers are already white and coated when you look, the spray is too late for those heads: cut off and destroy the worst ones, protect the rest at once, and start earlier next year.

Watch for the mosquito bug's damage as the tree flushes and flowers — dark, sunken spots on shoots, flower heads and young nuts, blackened tips, and the slender, long-legged bugs themselves.

At the first real damage, spray a registered insecticide, repeating every 10-21 days only while the bug is active — target the tender flush, flowers and young nuts where it feeds.

Spray in the cool hours (early morning or late afternoon), with the wind behind you, covering skin, eyes and nose, and keeping the spray off food crops.

Where you have weaver ants (the fierce ants that build leaf-nests up in the tree), leave them alone — they hunt the mosquito bug for free and can hold it down with no spray at all.

Every 7-10 days while the nuts and apples are growing, check a sample of nut-bearing shoots across the orchard — especially after rain.

Look for anthracnose: dark, sunken spots, some with pink or orange specks in the middle, on nuts, stalks and leaves — worst in warm, wet spells.

Look for nut scab: rough, scabby, corky patches on the skin of the young nuts.

If disease is spreading in wet weather, protect the crop with a fungicide, and remove badly spotted or shrivelled (mummified) nuts and shoots — they carry the disease over to next season.

About two months after flowering started — a couple of weeks before the first nuts drop — get ready to harvest.

Clear and smooth the ground under and around each tree — cut the weeds and rake it clean — so fallen nuts are easy to see and pick up and do not hide in the grass.

Line up your helpers, baskets or open bags, and drying space for a long harvest — the drop runs about 6-10 weeks, with visits every few days.

Plan to collect often — weekly, and daily in wet weather — because a nut left on damp ground quickly spoils or sprouts.

Let the fruit ripen and fall by itself — never pull nuts off the tree. The sign of ripeness: the cashew apple is fully coloured (red or yellow) and the whole apple-and-nut drops, and the nut is grey-brown and hard.

Walk the cleared orchard floor and gather the fallen nuts every 3-7 days — daily in wet weather — before they spoil.

Twist the nut off the apple. Keep the nuts; the fleshy apple spoils within hours, so eat, use or discard it the same day.

Put the nuts in baskets or open bags — not sealed sacks, which make them sweat and mould — and take them to dry that same day.

If an apple is still green, firm and clinging to the branch, it is not ready — leave it. Only gather what has fallen; nuts taken early are poorly filled and worth little.

As you collect, twist or snap the nut off the bottom of the apple — when ripe, they part easily.

Put the nuts in one basket, to go for drying, and the apples in another, for use the same day.

Use the apples within hours — eat them fresh, or make juice, jam or a dried snack — because they spoil the same day and cannot be stored.

Keep both baskets out of the sun while you work, so neither the nuts nor the apples cook and spoil.

As you collect each batch, spread the raw nuts in a single layer on a mat, rack or clean hard surface — never on bare, damp ground, which pushes damp back in and adds mould, grit and dirt.

Sun-dry them for about 2 hours a day over 1-3 days, turning them so they dry evenly, and bring them in or cover them if rain threatens.

Test for dryness: a well-dried nut rattles when you shake it (the kernel has shrunk away from the shell), and the kernel inside is hard, not soft or bendy — that is about 8-12% moisture.

Store the dry nuts in clean, dry bags in a cool, dry, airy place — off the floor and away from the wall — and check them now and then for damp or mould.

If a nut does not rattle, or the kernel is still soft, it is not dry enough — dry it more before storing, or it will mould in the bag.