How to grow sorghum

Think back over last season: did the crop show small purple or pink weeds at the base of the plants, or patches that stayed stunted and yellow? That is Striga — plan against it now.

Where you can, don't grow sorghum on the same land two years running. Follow it with, or grow it alongside, a legume — cowpea, groundnut, bambara nut or desmodium — which starves out Striga and fixes nitrogen.

If Striga is bad, plan a trap crop: a strip of the legume that makes Striga seeds sprout and die before you bring the land back to sorghum.

If you have a choice, pick the field with the better, deeper soil for sorghum — poor, hungry soil is exactly where Striga hits hardest.

Only lime if a soil test — or past crops that stayed yellow and stunted even with fertiliser — tells you the soil is sour. Sorghum tolerates mild acidity, so don't lime out of habit.

Your recommendation gives the amount for your field. Spread it evenly over the whole field, like sprinkling flour by hand — patches give patchy results.

Work it into the topsoil with a hoe or plough. Lime only helps the soil it is mixed into; left on top it does almost nothing.

Do it 1–3 months before you sow — lime is slow, so late liming won't help this season.

Buy certified, treated seed from a registered dealer — a sealed, labelled bag with the variety name and this season's packing date. The seed dressing (often a pink or blue coating) guards against smut, downy mildew and early shoot fly.

Choose a variety for your rains and your problem: a short-season type where rains are short; a bird-resistant (brown, tannin) type where birds are bad; an even-flowering, midge-tolerant type where midge is common.

Buy the basal fertiliser your recommendation gives — sorghum needs only a modest amount, so don't over-buy. A compound such as Compound D / NPK is typical, and your recommendation may add a little zinc or sulphur if your soil is short of them.

Store seed and fertiliser dry, off the floor, away from food, water and children. Keep the label and receipt in case the seed turns out poor.

Clear weeds and old crop residue off the planting lines (you can leave residue between the rows as mulch).

Loosen the soil to about 10–15 cm and break the clods on top to a fine, crumbly tilth — the smaller the seed, the finer the bed must be.

Firm the bed by treading or rolling it lightly, so the small seed will sit on solid, moist soil and not drop into air pockets.

Level the surface so water doesn't pool. On a slope, work across the slope (not up-and-down), or make basins or tied ridges to catch and hold every drop of rain.

Use only well-rotted manure or compost — dark, crumbly, no strong smell. Fresh, strawy manure needs more time to rot.

Spread it evenly — about a wheelbarrow every few strides gives a good rate.

Work it into the topsoil 1–2 weeks before planting, so it settles in with the soil.

Wait for a real planting rain that wets the soil deep and warms it (≥15–18 °C, comfortably warm to your hand) — sorghum rots in cold, wet ground.

Open shallow furrows about a stride apart (≈60–75 cm) between the rows.

Sow the small seed thinly along the furrow, only one finger-joint deep (2–5 cm) — never deeper, or the tiny seed can't reach the light. You'll thin to final spacing later.

Run the basal fertiliser as a thin band along the furrow, to the side of and just below the seed — never touching it, or it burns the sprout. Sorghum needs only a light dose.

Cover lightly and firm the soil, so the seed sits snug in moist earth and comes up strongly.

Sow in one block at the same time as your neighbours — spread across the whole area, shoot fly and birds are diluted; on a lone, late field they gang up.

Twice a week, walk a large “W” across the field so you cover all four corners and the middle, not just the edge by the path.

At about 10 stops, look closely at 10 young plants. Shoot fly: pull gently on the central leaf — if it slides out dead and smells rotten, that is a “deadheart” (the maggot has cut the growing point).

Look for damping-off: seedlings that keel over with a pinched, watery, rotten spot at the soil line, worst in wet patches.

Watch too for birds scratching up just-sown seed or pulling out young seedlings along the rows — press the soil firm again over any lifted seed and re-sow bare patches while the crop is still young.

Count how many plants in 100 show fresh deadhearts, and note the gaps (empty spots along the row).

If more than about 1 in 10 plants are deadhearted → pull and destroy the hit plants and lean on tillers and gap-filling to rebuild the stand; a light hit, sorghum often grows out of on its own.

Once plants are a hand tall (about 2 weeks after sowing), thin to one plant every 10–20 cm along the row — a hand-span (≈20 cm) apart where it is dry so each plant has more water, and about half that (≈10 cm) where rain is reliable.

Snip the extra seedlings off at ground level rather than pulling them, so you don't disturb the roots of the plant you keep.

In big gaps, drop a fresh seed if the soil is still moist and the crop is only a week or two old, or let a strong neighbour tiller into the space.

Aim for an even, unbroken stand — steady spacing beats a few crowded clumps and bare patches.

Weed by about 2–3 weeks after sowing, before the weeds get bigger than the sorghum.

Hoe shallowly between and within the rows — deep hoeing near the plants cuts the crop's roots.

Remove weeds fully (roots and all where you can); chopping only the tops lets many regrow.

Pull any small Striga seedlings at the plant bases now — every one you remove before it flowers is thousands of seeds kept out of your soil.

Keep the topsoil moist but not waterlogged while the crop establishes — sorghum takes short wet spells but hates standing in water.

Water lightly every 4–7 days, more often on sandy soils and in heat.

Check by pushing a finger in: water when the top few centimetres are dry.

Twice a week, walk the “W” and check about 10 plants at 10 stops.

Stem borer: look for neat rows of “shot-holes” across unfolding leaves, sawdust-like droppings in the whorl, and deadhearts in older plants; split a suspect stalk to find the tunnelling caterpillar.

Striga: look for small purple or pink weeds breaking the soil right at the sorghum bases — the ones you can see mean many more are latched on underground.

Aphids: turn leaves over and look for colonies of soft green or grey insects, sticky honeydew and black sooty mould; watch for ants farming them.

Write down what you find and where. If fresh borer shot-holes or deadhearts show on more than about 1 in 10 plants, or aphid colonies cover most of the top few leaves → act, and open the matching pest guide.

Weed again before the canopy closes — roughly 4–5 weeks after sowing.

Hoe shallowly so you don't damage the now-spreading roots.

Time it just before the nitrogen top-dress, so the feed goes to the crop and not to weeds.

Pull any Striga you find while you are down the rows.

Top-dress when the crop is about knee-high, on moist soil (after a weeding or a light rain).

Band the main nitrogen dose (about half to two-thirds of the season's N) that your recommendation gives, a hand's width (≈10 cm) to the side of the row — not on top of the plants.

Cover it or water it in, so it doesn't gas off into the air and go to waste.

Keep the fertiliser off wet leaves — the grains stick and scorch them.

Walk the rows every 7–10 days through this stage and look for the small purple or pink Striga plants at the sorghum bases.

Pull them out whole, gently, so the stem doesn't just snap off and re-grow.

Burn or bury what you pull — never leave it lying, and never let it flower and set seed.

Keep the crop well-fed and clean — a vigorous, well-nourished sorghum suffers far less from Striga.

Water only every 7–12 days through vegetative growth — let the crop lean on its deep roots and drought-toughness.

If you must choose, hold water back now and keep it for the flowering stage ahead.

Only step in if the crop is rolling its leaves tightly for days on end and clearly checked — a little leaf-rolling in the midday heat is normal for sorghum.

From the moment heads start flowering, check them daily in the morning — midge is busiest on the open florets between about 9 and 11 a.m.

Look for tiny bright-orange flies the size of a pinhead resting or darting on the flowering heads — a few is a warning, many means act.

Watch for florets drying to a blasted, grain-less tip — the sign midge has already been at work.

Note the first birds scouting the field — they'll return in flocks once the grain softens, so plan your scaring now.

If midge is heavy at flowering → act, and open the sorghum-midge guide, treating in the morning while the flies are active.

Keep the soil moist right through booting, heading and flowering — this beats every other watering of the season.

Water every 5–7 days, more often in heat, and never let the crop wilt into flowering.

If a heat spell above ~35 °C is coming onto flowering, water ahead of it to carry the crop through — a head stressed at flowering never fills.

Walk the whole field and pull every remaining Striga plant, whole, before any of its flowers open.

Burn or bury what you pull — don't leave it to seed on the ground.

Note the worst patches, so you can plan a legume rotation or trap crop there next season.

Start guarding from soft-dough (squeeze a grain — it's soft and doughy inside) and keep it up every day until harvest.

Guard hardest through the danger hours — early morning and late afternoon — when flocks feed most.

Use noise and movement: shout, bang tins, crack a whip, and string rattling scare-lines, flags and shiny strips across the field; move them about so birds don't get used to them.

Take turns with family or neighbours and scare as a community — a lone guarded field just pushes the flock next door and back.

Where birds are severe, choose a bird-resistant (brown, tannin) variety next season — the bitter coat makes birds move on.

Once a week, check a sample of heads and look over the standing crop.

Grain mould: look for grain going pink, grey, black or fuzzy, and heads that look weathered — worst where humid weather meets ripening grain.

Lodging: look for plants leaning or snapped, especially after wind or storms, or where nitrogen was heavy.

Watch the field edges for bird and rodent damage as the grain hardens.

If mould or lodging is spreading → cut and dry the affected heads early rather than let them rot in the field.

Keep watering through the milk and soft-dough stages, while the leaves are still green and the grain is filling.

As the lower leaves dry and the grain hardens, taper off the water.

Stop watering as the crop nears maturity, so it can dry down in the field — wet soil at ripening feeds mould.

Check for maturity: pull a few grains and look where each joins the head — a dark black layer there, and grain so hard you cannot dent it with a thumbnail, means the crop is ripe.

Cut the heads (panicles) with a knife or sickle, leaving a hand-length of stalk to carry them by. (Dwarf grain types can be combined where machines are available.)

Harvest promptly once mature where birds, mould or rain threaten — don't wait for a perfect field dry-down if the grain is at risk.

For sweet sorghum, cut the stalks at soft-dough and press for juice within 1–2 days; for forage, cut early, at boot (the head still wrapped inside the top leaf) to early head.

If the grain isn't yet hard and black-layered → leave it to ripen and keep scaring birds; but if birds or storms are winning, cut now and finish drying under cover.

Dry the cut heads or threshed grain on a clean raised surface — a mat, tarpaulin, rack or crib — never on bare ground, which pushes damp back in and adds mould, stones and animal dirt.

Spread it thin and turn it regularly so it dries evenly; cover it or bring it in if rain threatens.

Bite test: the grain is dry enough when it is hard and cracks or shatters — not bends or squashes — when you bite it.

If a grain bends or dents instead of cracking → it is still too wet; keep drying, and do not store it yet.

Thresh only once the grain is fully dry — beat the heads on a tarpaulin or in a sack, or rub them, to knock the grain free.

Winnow out the chaff, dust and broken grain by pouring the grain in a breeze or in front of a fan.

Pick out any mouldy, discoloured or insect-damaged grain — keep it out of the store, and don't eat visibly mouldy grain.

Store only grain that has passed the bite test — hard, cracking not bending (≤12–13%). Damp grain in store is where losses begin.

Store in hermetic (airtight) bags (PICS) or a clean, sealed granary or metal silo — airtight storage suffocates weevils and grain moth with no chemicals.

If you use ordinary bags, mix in a recommended grain protectant, and keep the bags off the floor and away from the wall, in a cool, dry place.

Check the store once a month for heating, moths, or grain with small round holes — act early if you find them.

If you find damp or heating grain → take it out and re-dry it before mould sets in and spreads.