Growing Yam in Ghana: Mounds, Staking and Harvest

Nine months underground: why yam asks for patience

A yam is the only staple most of us plant once, leave alone for close to nine months, and then dig up in one go. Nothing about it is quick. The tuber needs a long, steady season to bulk up, and farmers who grow it well tend to plan the whole year around that season.

Ghana grows several yam species, but the one most people mean is white yam, Dioscorea rotundata. Yellow yam (D. cayenensis) is the other major table yam, and water yam (D. alata) suits wetter places with a longer season. Trifoliate yam (D. dumetorum) grows wild in many bush areas and is eaten locally, though most growers do not plant it for market.

The mistake that costs yam growers the most is planting late. A field planted in late April that then meets a dry spell in July will often give small tubers by December, and no amount of later care fully makes up for it. Yam rewards early planting and punishes gaps in the rains.

White, yellow or water: picking the yam for your land

Pick the species before you pick the field. The table gives the broad picture. Ask your local agric extension officer which varieties are currently recommended for your district, because released varieties change over time.

For a first farm we would start with a white yam that your neighbours already sell well. Local buyers know its shape and how long it keeps, and you will not be learning the crop and the market in the same season.

If you want to see which birds suit a first holding alongside the yam, the breeds page is the place to start.

Matching the planting date to the forest, transition and savannah zones

Rain decides when you plant, and the zones differ. The forest areas, including much of the Ashanti, Eastern and Western regions, get two rainy seasons, a major one from roughly April to July and a minor one later in the year. The transition belt around Bono, Ahafo and Bono East has a shorter spell of rain and a clearer dry season. The northern savannah, covering the Northern, Savannah and Upper regions, has one rainy season from about May to October, so yam goes in later there and needs a variety that matures inside that window.

The Central Region and the coast near Kasoa follow a two-season pattern too, but the soils are often sandy and dry out quickly. Mounds there need extra mulch, and the safe planting window is narrower than people expect. Harmattan, the dry dusty wind from December to February, sits on top of all of this. It dries mounds fast and can scorch young leaves if you plant too early.

The safe rule is to plant when the soil is wet to the depth of a spade and the forecast suggests the rain will hold for several weeks. Planting on the first shower is a gamble. Two weeks of follow-up rain is far more reliable. Your district MoFA office will have the local planting calendar, and it moves from year to year.

Seed yam: minisetts, dormancy and where clean planting material comes from

Seed is where most failed yam fields start. A tuber that looks sound on the outside can carry virus, nematodes or rot inside, and once it is in the mound you cannot take it back out. Buy seed yam from a grower who can tell you where it came from, or raise your own from plants you have checked yourself.

Many farmers cut a large seed tuber into pieces called minisetts. Each piece needs at least one healthy bud, and the cut faces should dry and then be dusted before planting. Wood ash is a traditional dust, and some growers use a seed fungicide that extension staff recommend. Use any product exactly as the label says, and keep it away from children and from the chicken house.

Yam tubers rest for a period after harvest, a dormancy that can run from several weeks to a few months depending on the variety. Do not force sprouting with unlabelled chemicals. Seed that is ready will show buds on its own, and that is the time to plant. Planting seed that is still dormant leaves the mound bare for weeks, and weeds take the space first.

• Choose seed from a grower who can name the variety and the field it came from.
• Reject tubers with soft spots, cracks, dark streaks or a sour smell.
• Cut minisetts with a clean knife and dry the cut faces before planting.
• Keep seed in a cool, shaded, ventilated place until the day you plant.

Building mounds that drain in the rains and warm up fast

A yam mound is a raised heap of loose soil that lets water drain away from the seed and gives the tuber room to swell. On most Ghanaian farms the mound is roughly 30 cm high and about a metre across, with mounds set about a metre apart each way. Treat those figures as a starting point. Heavy clay needs taller, flatter mounds that shed water, and very light sand needs a little more soil and mulch so it does not dry out.

The soil in the mound is the yam's fertiliser store, so put the manure in before the seed goes down. Composted poultry manure works well. Fresh litter is too hot and too salty for a young sprout, and it can burn the bud. Let it compost under cover for several weeks first. The composting method in our poultry litter guide applies to yam manure too, and the manure rates and storage notes are a good place to start.

Build the mounds on a dry or nearly dry day so the soil crumbles instead of smearing. Break the clods, pull the soil into a ridge, and tamp the top lightly with the back of the hoe. Mounds built into wet clay set like brick, and the tubers will struggle to push through them.

Planting on the mound and mulching the top before the sun does

Plant the seed piece with the bud pointing up and the cut face down, about 10 cm into the mound. Cover it, press lightly, and spread a handful of dry grass, leaves or straw over the top. Mulch keeps the surface moist, keeps the soil cooler in the harmattan, and stops rain from crusting the mound.

Walk the field after the first heavy shower. Replace any seed that has rotted or failed to sprout within the first few weeks. Replanting gaps early is cheap work. Replanting in August is a much harder job, and by then the weeds are already ahead of you.

Keep the edges of the field clean as well. Yam can carry nematodes and virus that move in from neighbouring bush, and cutting a clear border of grass or bush around the plot reduces the insects that reach the young plants.

Staking: when to put the sticks in and how tall they should be

Yam is a climber, and the vines will find each other and wrap into a tangle if you let them. Once that happens, the leaves cannot spread out to catch light, and the crop shrinks. Put the stakes in when the vines are about 30 cm long, usually four to six weeks after the shoots come up. Too early and you may damage the sprout. Too late and the vines have already crossed the mound.

Stakes are usually 2 to 2.5 metres tall, pushed about 30 cm into the ground and set close to the mound. Bamboo, cut palm stems and durable local wood all work. Tie the vines loosely with twine or strips of cloth, and check the ties after the first heavy storm, when the vines are at their heaviest and the wind is strongest.

Staking takes more labour than most people budget for. Count the stakes you need before you buy anything, and plan the labour days around that count rather than around the calendar. A field left unstaked for even a few weeks can take a season to recover its shape.

Weeding and hilling a crop that stays in the ground all year

The first eight weeks decide how much weeding you will do for the rest of the season. Clear the weeds around the mounds by hand with a hoe kept shallow, because yam roots and developing tubers sit near the surface and a deep cut will damage them. Once the vines and leaves cover the ground, the weeds start to lose the light and fade out.

Hilling means drawing a little soil back up onto the mound. Do it once or twice in the early months, after weeding and never in the middle of a soaking rain, so the tuber grows straight and stays covered.

On poor soils, yam responds more to potassium and organic matter than to nitrogen alone. Too much nitrogen can push the plant into leaf at the cost of tuber size, which is a common and expensive surprise. Use your extension officer's soil advice where you can, and keep the manure on the mound rather than scattering it over the whole field.

Tuber beetles, yam nematodes and virus: what to scout for

Yam has a short list of problems, but each one can take a big share of a field. The yam tuber beetle, Heteroligus meles, does serious damage in storage and in the ground. Its larvae tunnel into tubers, and the holes open the way for rot. Look for small holes and frass in harvested tubers, and check the barn each week. Ask your extension officer which control is currently recommended, since options change and not every product is registered.

Nematodes that attack yam tubers cause dry, dark rot inside the tuber, which is easy to miss until someone cuts into it at the market. Yam mosaic virus shows as mottled or distorted leaves and spreads through aphids and infected seed. You cannot cure a virus once a plant carries it, so remove infected plants early and never save seed from them.

Anthracnose, a fungal disease, brings dark spots on leaves and stems, especially in wet weather. Rotation, clean seed, proper spacing and removing infected material from the field are the first defences. Chemicals come last, and only when your local advice says so. Check the label and the waiting period before harvest every time.

• Walk the field every week and pull out plants with mottled or distorted leaves.
• Cut one or two tubers from each batch in storage and look for lesions before the barn fills up.
• Keep weeds and volunteer yam plants away from the new field.

Digging time: vine die-back, the thumb test and dry ground

Most white yam varieties need roughly eight to ten months from planting to harvest, though early types can be ready sooner and late ones take longer. Calendar months only give an estimate. The crop tells you when it is ready. The vines turn yellow, then brown, and die back from the top. When most of the leaves have fallen and the vine is brittle, the tubers have finished bulking.

Digging early gives you small tubers with thin skins, which bruise easily and rot faster in the barn. Digging very late, after several dry weeks, toughens the skin and can crack tubers as the soil shrinks. Choose a dry spell and dig when the soil is moist enough to lift the tuber cleanly but not wet enough to smear.

Use a fork or a sharp hoe, dig in a circle around the mound at arm's length, and lift the tubers out whole. Every cut or bruise is a door for rot. Put the harvested yams in the shade, not the sun, and do not stack them in heaps on bare ground.

Curing and storing yam so the tubers keep for months

Curing means letting freshly dug tubers dry in shade for a few days so the skin toughens and the cut ends seal. Lay them out in a cool, airy place, turn them once, and sort out any that are already soft or cut. Cured yams keep much longer than fresh ones dug on a hot afternoon and loaded straight into a sack.

A traditional yam barn is a ventilated structure raised off the ground, with walls of sticks or wire, a roof that sheds rain, and room for air to move between the tubers. Some farmers store yams in heaps on a platform, others in sacks or crates. Whatever you use, keep it dry, keep it off wet ground and check it every week. Pull any soft tuber and throw it away. One rotten yam can infect its neighbours within days.

Storage life is measured in months, not years. Most farmers plan to sell or eat the crop within the first few months, and they keep a small batch back for seed. Mark the seed batch clearly so you never mix seed with eating yam when you go to the barn.

A barn full of yam is also a shelter for rats, insects and the debris they feed on. Clear out old sticks and sacks between seasons, and check the floor for holes and droppings. Keep chickens out of the barn, because birds scratch at the floor and carry soil and rot from one place to another.

Selling yam: festival demand, the market calendar and current rates

Yam has a demand that moves with the calendar. Festivals across the Akan and Ga areas, including Homowo for the Ga, Fetu Afahye in Cape Coast and Odwira in Akuapem, drive sales in the weeks around them. Weddings, funerals and ordinary home cooking of yam with palm oil keep the everyday market busy too. Some buyers pay up front in the weeks before a festival, while others wait until the yam is cut and inspected.

We do not quote yam prices, and neither should you without checking. Rates change with the season, the size of the crop in your area, the variety and the state of the roads. Ask at the market where you plan to sell, talk to the traders who buy for festivals, and check current rates in your district before you commit to any sale.

Grade your yams before they reach the market. Keep the big, sound tubers together, sell the broken or bruised ones quickly or use them at home, and never hide damaged yams at the bottom of a sack. A reputation for clean sacks brings the same buyers back next season.

A worked plot: half an acre, one season, and the labour you will need

Here is a plot plan you can check against your own land. Half an acre is roughly 2,000 square metres. At a mound spacing of about one metre each way, the field holds roughly 2,000 mounds before you allow for paths, the edges and bare ground. Every mound needs one seed piece, so buy or cut for that number plus a margin for failures. Ask your grower how many seed pieces they expect to lose in the first month.

Count the stakes too. If you stake every mound, you need about one stake per mound, plus spares for breakage. Twine or cloth ties, poles for the barn and mulch all belong on the list. Write each item down with a quantity and a source, then price it at your own market. The rates that matter are the ones in your town on the day you buy.

Labour is the cost most farmers leave out. Count the days for mounding, planting, two or three weeding rounds, staking, tying, digging, curing and carrying to the barn, and add the checks you will make during storage. A family can cover half an acre, but the timing of the work decides whether the crop lands on time.

Work the plan in this order:

1. Confirm the variety and the planting window with your district MoFA office.
2. Source and cut seed, then dry and dust the cut faces.
3. Build mounds and work in composted manure before the first real rains.
4. Plant, mulch, and replant gaps in the first month.
5. Stake at four to six weeks, then tie vines after each storm.
6. Weed twice in the first two months and scout every week.
7. Dig after die-back, cure in shade, and check the barn weekly.

Many yam growers also keep a flock on the same holding. If you are thinking about birds, our day-old chicks page lists the breeds we hatch, and the starting prices are on the prices page. Message +233 24 915 1503 on WhatsApp if you want help choosing the first batch. You can also read the record keeping guide to track the birds and the yam side by side, and our integration article shows how the two fit on one farm.

Growers who want to work with us on a larger scale can read the partner page, and when you are ready to buy, the order section has the details. For the next crop to try alongside yam, the sweet potato guide and the tomato guide cover quicker crops that fit the same farm.

Questions farmers ask