How to grow cocoyam and taro

Make this choice in the month before planting, before you shape the ground — there are two ways to grow taro, and you pick the one your land and water actually suit.

Wetland (paddy) taro — choose it only if you have water you can rely on all season and flat, water-holding ground (heavy clay or clay-loam). You build bunds (low walls of packed soil around the plot) to hold a shallow sheet of water, like a rice paddy. It gives the highest yields and smothers most weeds — but it needs water you can count on for many months.

Upland (dry-ground) taro — choose it where your water comes from rain or the odd watering and the land drains freely. You keep the soil steadily moist but never flooded; dry-ground taro rots if it stands in still water. Yields are lower than a paddy, but it works where you cannot hold standing water.

Match the choice to your own water and soil, not your neighbour's: low, flat, wet-bottom land near a stream suits a paddy; free-draining ground suits upland. Fix your choice now — planting, watering and weeding all follow from it.

In the two weeks before planting, choose your planting material — small whole corms, cormels (the little side-corms), headsetts (the leafy top of a corm, cut off with a thumb-length of firm corm left on) or suckers (side-shoots). Any of these will grow — they are all called setts.

Take setts only from healthy, high-yielding mother plants — clumps with clean green leaves and no leaf spots, no rot and no yellow mottling.

Reject any suspect sett. Throw out any piece that is soft, rotting or smelly; any from a plant with dark, wet-looking spots on the leaves (leaf blight); or any from a plant whose leaves show a feathery pale-and-dark green mottle (mosaic virus). These sicknesses are inside the piece — you cannot wash them off.

Trim off old roots and any rotten patches with a clean knife, and let cut headsetts dry in the shade for a day or two so the cut skins over — a healed cut rots far less in the ground.

In the 2–3 weeks before planting, prepare the ground to match the water regime you chose.

Upland: dig the soil over deep so it is crumbly and free-draining, and make ridges or mounds if your ground tends to waterlog. Paddy: build the bunds (low soil walls) and puddle the wet soil — work it wet with a hoe until it is soft and slightly sealed underneath, so it holds water like a rice field.

Work in plenty of well-rotted manure or compost — dark, crumbly, with no sharp smell. Taro wants more organic matter than a quick crop like maize: spread it thick — a good wheelbarrow-load for every few strides of ground you cover (a stride is about 1 m) — and dig it into the topsoil.

Do this 1–2 weeks before planting so the manure settles in and any heat from rotting has passed before the setts go in.

Plant on your prepared ground at about 70 cm apart each way — roughly three to four hand-spans (a hand-span, thumb-tip to little-finger-tip on a spread hand, is about 20 cm). Even, generous spacing gives each plant room to build one big corm.

Set each sett 5–10 cm deep — about two finger-joints (a finger-joint is 3–5 cm) — with the bud pointing up. The bud is the pale, pointed eye the new shoot grows from; plant it downward and the shoot wastes days fighting to turn around.

Firm the soil gently around each sett so it sits snugly in moist earth, then cover it.

Upland: keep the soil continuously moist from planting day. Paddy: plant into wet, puddled soil and let the setts root and shoot first, then raise a shallow sheet of standing water over them — just a few centimetres deep, not a pond. Never drown a sett that hasn't rooted yet.

Be patient — taro sprouts slowly, often taking 2–4 weeks to show. Don't dig up 'failures' or gap-fill in the first couple of weeks; you'll pull up setts that were about to shoot.

From planting through about the first six weeks, tend the water every 5–10 days to suit your regime.

Paddy: keep the bunds sound and the soil puddled, and once the setts have rooted and started shooting, hold a shallow sheet of standing water over the field — a few centimetres deep, not a deep pond. Top it up as it soaks away or evaporates.

Upland: keep the soil steadily moist — push a finger in and water when the top few centimetres are dry. Never let it dry right out, but never leave it in a stagnant puddle either: upland corms rot in still, airless water.

Watch the weather — water more often in heat and on lighter soils, and less when it rains.

From about 3 to 6 weeks after planting — once slow-sprouting taro has had its time — walk the rows and count how many setts have pushed up a shoot against how many you planted.

Work out the share that came up (for example, 85 sprouted from 100 planted = 85%).

About 85 in 100 (85%) or more → a good stand, carry on.

While you're there, look at the young leaves for the first signs of leaf blight — small dark, wet-looking (water-soaked) spots that spread fast in damp weather. Pick off and carry away any spotted leaves at once.

If fewer than 85 in 100 sprouted → gap-fill the misses now with fresh, clean setts from a healthy plant, while there's still time for them to catch up. First scratch up a few non-sprouters: if they are soft and rotten, that's corm rot — replant with sounder setts and ease off the water.

Starting about 2 months after planting, and again every month or so, draw loose soil up around the base of each plant into a low mound.

Cover any corm shoulders showing above the ground — the pale or greening top of the swelling corm.

Work gently and shallow near the plant: taro's feeding roots sit shallow, and deep hoeing at the base tears them.

On upland ground, mounding also sheds heavy rain off the crown so water doesn't pool there and rot it.

Weed from about 6 weeks after planting, and again every 3–5 weeks (about once a month), until the leaf canopy closes over and shades out new weeds — usually 2–3 weedings in all.

Hoe or pull shallowly: taro's feeding roots are near the surface, so scratch the weeds out of the top of the soil rather than digging deep near the plants.

In a paddy you'll weed far less — the shallow standing water smothers most weeds by itself. Just pull the few that push through.

In dry areas, leave the pulled weeds lying between the plants as a mulch to hold moisture in the soil.

Walk the whole crop once a week — every few days in warm, wet, blight-favouring weather — and look closely at the leaves, the stems and a few plants' bases.

Taro leaf blight (the big one): look for dark, wet-looking (water-soaked) spots on the leaves, often with a yellow edge and, in the damp of morning, a faint fuzzy growth underneath. The spots spread fast, merge, and whole leaves rot, collapse and hang down. Pick off and carry away affected leaves on the very first spots — don't wait for it to spread, and never drop them in the field.

Taro beetle: look for wilting or collapsing plants; scratch at the base and you'll find holes and tunnels bored into the corm. Dig out and destroy any grubs and beetles you find — flooding a paddy helps drive them off.

Dasheen mosaic virus: look for a feathery pattern of pale and dark green running along the leaf veins, and crinkled, distorted young leaves. There is no cure — pull out and carry away badly mottled plants so they don't infect the rest, and never save setts from them.

Root-knot nematode (a tiny soil worm): if a plant is stunted and sickly for no clear reason, lift it and check the roots for knots or beads (little swellings). Where you find them, don't plant taro on that ground again next season — rotate to another crop.

From about 4 months to 8 months after planting, keep the water coming every 5–10 days — never let the crop go short while the corm is filling.

Paddy: hold the shallow standing water steady and top it up promptly; don't let a paddy dry out and crack now of all times.

Upland: keep the soil moist at all times — check with a finger and water before the top dries out. In heat, water more often.

If you can water at only one stage of the whole season, water now — this stage pays back water better than any other.

Around 4 to 6 months after planting, as the corm is bulking, give the crop its final potassium feed — a potassium fertiliser such as muriate of potash (MOP), or a K-rich compound. Your recommendation gives the exact amount for your field.

Band it — lay it in a line about a hand-span (≈20 cm) to the side of each plant, not on top of it — then cover it with soil or water it in so it isn't wasted.

Feed onto moist soil (after watering or light rain) so the potassium washes down to the roots.

Handle fertiliser safely: keep it off the leaves (wet grains stick and scorch), away from food, water and children, and wash your hands afterwards.

Keep walking the crop every 7–10 days — more often in warm, wet weather — right through the bulking months (about months 4 to 8).

Check the leaves for the same dark, water-soaked spots with yellow edges that spread and rot the leaf — that's taro leaf blight.

Pick off and carry away affected leaves as soon as you see them — strip the worst-hit leaves rather than let the blight run through the canopy. Never drop them among the plants.

Keep an eye out too for bored, wilting plants (taro beetle) and feathery pale-and-dark mottled leaves (mosaic virus), and rogue out any badly affected plants.

Wait for the plant's maturity sign: the leaves yellow, wither and die back, and a corm feels firm and full when you press or probe it. The wide window opens from about 7 months after planting (a paddy ~10–12 months, dry ground ~12–15).

If you grew a paddy, drain the water off first and let the field firm up for a few days — you can't dig clean corms out of mud, and standing water at harvest invites rot.

Loosen the soil around each clump with a fork or by hand, and lift the corms out gently — work wide of the plant so you don't stab the corm.

Handle every corm carefully — taro bruises easily, and a bruised corm rots. Set them down softly; don't tip or throw them into a heap.

If the leaves are still green and standing and the corm feels soft or small, it isn't ready — leave it longer and check again. The harvest window is wide, so there is never a need to lift an unripe corm.

As you dig, mark your healthiest, highest-yielding clumps — the ones with clean green leaves, no spots and no mottling, that gave the biggest, soundest corms.

From those clumps only, set aside headsetts (the leafy top cut with a thumb-length of firm corm) and small, clean corms or cormels for next season's planting.

Reject anything from a plant that showed leaf spots, mottling, wilting or corm rot — never carry a disease forward in your own seed.

Keep the saved setts cool, shaded and airy until planting, and let any cut surfaces dry so they skin over.

Handle gently — corms bruise, and bruised corms rot. Sort out any cut, bruised or soft corms to eat first; only sound, clean corms go into store.

Cure briefly: let the corms sit a short while in a cool, shaded, airy place so the skins firm up and small nicks dry over.

Store cool and airy — spread out, off the bare ground, out of sun and rain, where air can move around them. Taro does not keep for long, so check the store often and use the corms while they're still sound.

Always cook (boil, bake or fry) or thoroughly dry the corms and leaves before eating. Raw taro carries tiny needle-like crystals (calcium oxalate) that make the mouth and throat itch and burn; heat and drying destroy them.