How to grow lablab

Decide the main use now — up to about 4 months before sowing and no later than 2 weeks before — because it shapes everything else: dry beans to eat and sell, fodder or hay for animals, or a green manure (a crop you slash and dig back in while still green) to feed the soil and smother weeds. You can still take a little of each, but plan for the main one.

Match the type to the use: for dry beans, a bushy type in its own field is simplest; for fodder or ground cover, a spreading or climbing type sown thicker gives more leaf; for green manure, any vigorous type you will cut and dig in while green.

Choose a well-drained field. Lablab beats drought with its deep taproot but hates wet feet — avoid low spots and hollows that puddle after rain.

Rotate: do not plant lablab where lablab or any other beans grew last season. A fresh field — for example after maize or sorghum — starves bean pests and root diseases, and the nitrogen lablab leaves behind then feeds your next cereal crop.

In the 3 weeks before sowing, buy clean, whole, plump seed — unbroken, with no small round holes (a hole means a weevil is already inside). Buy enough for your field size; your recommendation gives the amount.

On land that has never grown lablab before, buy a sachet of Bradyrhizobium inoculant — the dark root powder of living root helpers. It is cheap, and it is the difference between a crop that feeds itself and one that goes hungry. Keep it cool and out of the sun — heat kills the helpers inside.

Lablab makes its own nitrogen, so do not buy nitrogen fertiliser (urea or AN — ammonium nitrate) for it — extra nitrogen only grows lazy leaf and can even switch off the free root-nitrogen. What it does reward is phosphorus (P), a root-and-flower nutrient: buy a small P starter (for example single superphosphate) only if your soil is known to be poor in phosphorus, or past bean crops came up weak and pale.

Store seed and any fertiliser dry, off the floor, away from food, water and children. Keep the inoculant sachet cool and safe for planting day.

In the weeks before sowing, clear the planting lines of weeds and old crop trash. You do not need the fine, powdery seedbed maize wants — lablab seed is big and pushes up through rougher soil.

Loosen the soil so rain soaks in and the deep taproot can drive straight down to reach water in a dry spell.

Fix drainage on heavy or low-lying ground: work across the slope, open a shallow drain to lead water away, or plant on ridges or mounds so the roots sit above any standing water.

In dry areas, instead make basins or tied ridges to catch and hold the rain — lablab uses light rain well, but the roots must never sit in a puddle.

First know your type: a bushy lablab (knee- to waist-high) needs no support — skip this task. A climbing type needs something to grip.

The cheapest support is a living one: grow the climber up maize or sorghum. Plan to sow the lablab into the cereal — either at the same time, or once the cereal is about knee-high (≈45 cm) — so the vines climb the stalks.

If you have no cereal, gather stakes, poles or a simple trellis (branches, reeds, or string strung between posts), enough for the field, ready for when the vines start to twine a few weeks after sowing.

Where you use a cereal as the support, space it so there is room for both — do not crowd the cereal so tightly that neither crop yields.

Sow into moist soil, once the rains have truly started — the seed needs steady damp for the 2–4 weeks it takes to come up. (Optional: soak the seed in warm water for about 2 hours first to soften the coat and speed the strike.)

On new land, coat the seed with the inoculant just before sowing: moisten the seed with a splash of clean water (or a little sugar-water so the powder sticks), sprinkle on the dark powder, and turn it until every seed is coated. Do this in the shade and sow within a few hours — sun and heat kill the living helpers.

Sow one or two seeds per station, 3–5 cm deep — about your first finger-joint — a little deeper in dry, sandy soil, shallower in heavy soil.

Space by type: climbing types wider apart — roughly a stride between rows (≈75 cm) and a hand-span and a half between stations (≈30 cm); bushy types closer and denser. The wider rows for climbers leave room for their support.

If you bought a phosphorus (P) starter (poor-P soils only), work a little into each station or band it beside the seed as you sow — never heaped on the seed, or it can burn the sprout.

Cover and firm the soil over the seed so it sits snug in moist earth, and keep the surface damp until the seedlings show.

From about a week after sowing, walk the field every 3–4 days — lablab emerges over two to four weeks, so keep checking as more seedlings appear.

Look for aphids: small soft green, grey or black insects clustered on the growing tips and under the young leaves, often with sticky, shiny honeydew (the sweet waste they leave) and ants running over them. A few are normal; dense colonies curling the tips need action.

Count the gaps: note the stations where nothing has come up. Some seed is just slow, but large bare patches may need re-sowing while the soil is still moist and the crop is only days old.

Rub out small aphid colonies by hand or with a splash of soapy water; ladybirds and hoverflies usually clean up the rest — only think about spraying if colonies explode across many plants.

From sowing until the seedlings are all up (about 2–4 weeks), keep the top few centimetres of soil moist — damp, never flooded.

Where you can water, wet the rows every 4–6 days, more often on hot days and quick-drying sandy soil.

Check with a finger: if the top finger-joint (3–5 cm) of soil is dry, water; if it is still damp, wait.

Once the seedlings are up and growing, ease off — the deep taproot soon finds its own water and the crop needs far less.

Keep walking the crop every 3–4 days through weeks 3 to 7 after sowing, checking the shoots and both the tops and undersides of the leaves.

Aphids: clusters of soft green, grey or black insects on the growing tips with sticky honeydew — usually cleaned up by ladybirds; act only on heavy, spreading colonies.

Cercospora leaf spot (a fungal disease): small round brown spots, often with a paler grey centre and a darker ring, scattered on the leaves. Bad attacks turn leaves yellow and drop them.

Rust (another fungal disease): tiny reddish-brown powdery bumps (pustules) on the underside of the leaves that rub off like rusty dust on your finger.

For the low levels this hardy crop usually shows, note it and keep the crop healthy: pick off and destroy badly spotted lower leaves, keep the weeds down for airflow, and only spray if disease races across much of the field.

Weed the first time by about 3 weeks after sowing, and again if needed by about 6 weeks after sowing — this is the critical weed-free window.

Hoe shallowly between and within the rows — lablab's feeder roots run near the surface, and deep hoeing cuts them.

Pull the weeds closest to the plants by hand, so you do not tear the stems, roots or twining shoots.

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

After this window, ease off — a well-established lablab canopy shades out most new weeds on its own.

Watch for the vines to start twining — sending out curling shoots that reach for something to wrap around (roughly 3–7 weeks after sowing).

If you planned a living support, this is when the lablab begins climbing the maize or sorghum. If you sowed the cereal separately, guide or thin the lablab beside it once the cereal is about knee-high (≈45 cm).

If using stakes or a trellis, push them in now — before the vines are long — and gently lift the first shoots onto them; the plant grips and climbs on its own after that.

Guide any shoots running along the ground up onto the support, so the plant grows tall and open instead of into a tangled mat.

From about 7 weeks after sowing (when buds and the first flowers appear), check the crop closely every 2–3 days — this pest moves fast.

Look into the buds and flowers, not just at the leaves. The Maruca pod borer webs flowers and young pods together with silk and hides inside — pull apart a few clusters of webbed flowers and look for a small caterpillar and its dark droppings.

The African bollworm (Helicoverpa) is a fatter, striped caterpillar that chews round holes into buds, flowers and pods — look for the holes and the dark droppings around them.

On about 10 plants at several spots, count how many flowers or young pods hold a caterpillar. Roughly one caterpillar per flower or pod — or webbed-and-bored flowers on many plants — means it is time to spray (see the spray task).

Glance too for aphids still on the shoots — usually minor by now, but note any heavy colonies.

Spray only if scouting crosses the threshold (about one caterpillar per flower or pod, or webbed-and-bored flowers across many plants) — never on a fixed calendar.

Choose a softer product first: Bt (a natural, caterpillar-killing bacterium, sold as a powder or liquid) or a neem spray — both hit young caterpillars while sparing bees and ladybirds. Use an approved chemical insecticide only if borers are heavy.

Aim at the buds and flowers, where the caterpillars feed — that is where the crop is being lost. Repeat after 10–14 days only if scouting still shows them over threshold.

Safety: spray in the cool of early morning or evening, with the wind at your back; cover your skin, nose and eyes; keep the spray off food; and wash yourself and the sprayer well afterwards.

Respect the pre-harvest interval — the waiting time printed on the label between spraying and picking — so no poison is left on pods you will eat or sell. This matters most on any pods you are picking green.

From flowering onward (about 7–11 weeks after sowing), keep the soil evenly moist through the flowering and early-podding stretch.

Where you can water, irrigate every 7–10 days, more often in heat or on sandy soil — but never leave the roots standing in water.

Watch the plants in the heat of the day: flowers and young pods dropping is the sign it is too dry — water before it gets that far.

This is the stage that most rewards water; once the pods are set and filling, lablab can once again ride out dry spells on its deep root.

Keep walking the crop every 3–4 days through podding and grain fill, checking pods of all ages.

Pod borers: round holes and dark droppings on the pods, with caterpillars inside — as at flowering. Pick and destroy badly bored pods.

Pod-sucking bugs: shield- or stink-bug-shaped bugs (green, brown or spotted) sitting on the pods; they leave sunken, dark spots on the pod wall and shrivelled, pitted beans inside. Knock heavy numbers off by hand, or spot-spray if bad.

Bruchid weevils: look on the maturing pods for tiny beetles and small eggs stuck to the pod skin. This is your early warning — those grubs bore into the seed and carry on eating it in store, so plan to harvest promptly and seal it.

Note what you find and act at the thresholds; on this hardy crop, hand-picking and spot action beat blanket spraying.

Start picking from about 10 weeks after sowing, when pods are young, flat, green and tender — before the beans inside swell hard and the pod turns stringy.

Pick every 3–4 days, taking the pods at the right stage and leaving the rest to grow on; regular picking keeps the plant flowering and podding.

Snap or cut the pods off cleanly without tearing the vine.

Cook green pods well before eating (boil them; do not eat raw) — like the dry beans, raw lablab does not agree with you.

If your plan is dry grain or seed, skip green-picking on those plants and let the pods fill and dry on the vine.

Start when the first pods are dry — from about 130 days (over 4 months) after sowing — and keep coming back every 7–10 days as more ripen. Grain fill is uneven, so one pass will never get it all.

Know a ready pod: it has turned dry, tan or brown and papery, and when you shake it the seeds rattle loose inside and feel hard (not soft or green). That rattly, papery pod is ready; a green or leathery one is not.

Pick the dry pods only, leaving the greener ones to ripen for the next pass. Pick in the cooler morning, when pods are less brittle and shatter less as you handle them.

Do not wait for the whole field to dry — the earliest pods will have shattered by then. Little and often beats one late pass.

Shell the picked pods, then dry the beans and store them weevil-tight (see the drying-and-storage stage).

If the pods are not yet dry (still green or leathery, the seeds soft) → leave them to ripen on the vine and come back in a few days; only pick pods that are papery and rattle.

Dry the beans hard in the days right after harvest — spread them on a mat, rack or tarpaulin (never on bare ground, which pushes damp back in and adds mould and dirt), turn them, and cover them if rain threatens. They are dry enough when a bean is too hard to dent with a fingernail and cracks rather than squashes when you bite it.

Winnow out the chaff, dust, broken beans and any holed ones (pour the beans in a light wind so the trash blows away) — weevils breed fastest in the trash and the damaged seed.

Store in airtight (hermetic) storage — PICS or triple-layer bags, or a clean, sealed drum or airtight container. Sealed tight, the trapped weevils use up the air and die, so no poison is needed. (A traditional stand-in is coating the beans with wood ash, which blocks the weevils.)

Keep the store cool, dry, off the floor and away from the wall, and check it once a month for small round holes, fine powder, or moving weevils — act early if you see them.

Before eating, remember the mature dry beans carry natural antinutrients (substances that upset your stomach raw): soak them, throw away the soaking water, and boil them well — never eat lablab raw or half-cooked.