Short answer: A protected house lets you grow tomato, pepper and cucumber through the rainy season, when open-field disease takes much of the crop, but it also traps heat and pests that a field would shrug off. Pick the site and the ventilation first, then the structure, and only then the seed. Most greenhouse failures in Ghana come from heat and whitefly, not from the price of the frame. We are a chick hatchery and do not build or sell greenhouses, so treat this as planning guidance for a poultry keeper weighing a second enterprise.
Key takeaways
- Choose the site for afternoon shade from trees, a steady breeze, drainage and a dependable water source before you order any frame.
- A net house with generous side vents usually beats a sealed tunnel in the Ghanaian heat, because trapped air cooks the crop.
- Insect-proof netting and shade cloth do more against whitefly and thrips than most sprays, and they cost less over a season.
- Solarise the soil in the dry season and feed the crop through drip lines, so you control the water and the nutrients.
- Count back from the market date you want, since a crop planted in the wrong month lands in the glut and sells for little.
Start with the site, not the frame
Ask a farmer why a greenhouse failed and the answer is often the same: the house sat in the wrong place. It caught the full afternoon sun on a bare slope, or it sat in a hollow where the rains pooled after every storm, or the nearest borehole was a long walk with a bucket. The structure itself was fine. The site was never worked out.
Before you buy anything, walk the plot at three times of day. Mark where the shadow of the nearest tree falls at noon and at four in the afternoon. Watch which way the wind blows during the rains, because a house that funnels air across its vents is much easier to keep cool than one that sits in dead air behind a wall. Dig a hole in the corner of the plot after a heavy shower and see how long the water takes to drain away.
Water and power come next. A protected crop wants irrigation every day in the hot months, and a net house in the south can stand in full sun for most of the year. Work out how far the water source is, how you will move it, and whether you have a drum, tank or tap at the entrance. If you plan fans or a pump on electricity, find out how often your area loses supply and whether a generator or battery backup fits the budget.
Keep the site close enough to watch every morning. Most greenhouse losses are small problems that were seen a week late: a wilted leaf, a patch of white flies under one plant, a leaking drip line. A house twenty minutes away from home gets visited less often, and it shows in the yield.
Choose the structure: net house, tunnel or glasshouse
Three kinds of protected structure turn up on Ghanaian farms. They differ in how much they keep out, how much heat they hold and how much they cost to put up, and the sensible choice depends on the crop and the rain you get.
A net house is a frame covered with insect-proof mesh, sometimes with a shade cloth on top. It keeps out whitefly, thrips and most of the flying pests, and it lets air move freely. In the rainy season it still lets in rain on the crop, so it does not stop fungal disease on its own. A net house suits most vegetables grown in the forest and coastal zones.
A polythene tunnel is a curved frame covered with plastic film. It keeps rain off the leaves, which is a real advantage against blight and leaf spots, but it traps heat quickly. Tunnels need tall sides, roll-up vents and a plan for shading from the start. Film needs replacing every few seasons, because UV breaks it down.
A glasshouse, with rigid panels and a steel frame, is the most expensive option and the least common among small and medium farms in Ghana. It suits high-value crops and a farmer with a strong market, and it needs the most attention to ventilation and power.
| Structure | Keeps out | Main weakness in Ghana | Suits |
|---|---|---|---|
| Net house with shade cloth | Whitefly, thrips, most flying pests | Does not keep rain off the leaves | Tomato, pepper, cucumber, leafy greens |
| Polythene tunnel | Rain, some insects if sealed | Traps heat and humidity fast | Lettuce and leafy greens in cooler months, seedlings |
| Glasshouse | Rain, insects, wind | High build cost and power needs | High-value crops with a strong buyer |
Whatever you choose, ask the supplier for the mesh size, the film grade and the warranty in writing. Ask what the vents open to. A structure that cannot vent is a sauna.
Heat and humidity: the problem you did not plan for
Inside a closed house on a bright March afternoon, the air can run several degrees hotter than the open field a few metres away. Tomato flowers drop when it gets too hot, pollen becomes sticky and fails to shed, and fruit set falls away. Peppers do the same. Leafy crops bolt and turn bitter. The crop does not die at once, which is what makes heat so easy to miss until the harvest comes in light.
The coast is the reverse problem. Humidity stays high for much of the year, so leaves stay wet, spores settle and fungal disease spreads. A tunnel in a humid zone needs more ventilation than a tunnel in the north, not less, even though it is cooler outside.
Three practical steps help in most of Ghana. First, shade the roof with a cloth of around 30 to 50 per cent shade, and check with your supplier which density suits your crop and zone. Second, open the side vents in the early morning and keep them open through the day. Third, wet the path between the beds, not the leaves, in the late morning, because the evaporation cools the air around the crop.
Put a cheap maximum thermometer inside the house and read it every morning. A number you write down every day tells you more than a feeling at four in the afternoon.
Ventilation and netting you can actually maintain
Ventilation is a daily task, not a feature you install once. Roll-up sides, end doors and gable vents all matter, but only if somebody opens them at six in the morning and closes them before the evening damp settles. Put a note on the door, or set a phone reminder, until the routine is automatic.
Netting needs the same attention. A net with a torn corner lets in whitefly and thrips through the gap, and a pest colony starts from one plant. Walk the perimeter after every storm and every time you feed the animals next door. Seal the door with a flap or a double door. A simple habit is to keep a strip of mesh and a stapler in the store, so a tear is fixed the same day.
- Open the sides and doors at dawn, once the leaves are dry.
- Walk the net edges and check for tears, gaps under the skirt and loose staples.
- Check the shade cloth after strong winds and retie any loose corner.
- Close the house at dusk, or leave the top vents open where the design allows, so cooler night air moves through.
Keep the mesh clean. Dust and dried leaves block light and air, and a dirty net needs regular rinsing with water. Do not use a harsh chemical on the mesh unless the supplier says it is safe, because some cleaners weaken the fibre.
Soil, raised beds and solarisation in the dry season
Most greenhouses in Ghana are built on the soil that was already there, and that soil has been farmed, possibly for years. Nematodes, soil fungi and the seeds of weeds gather in the top layer. A house built on tired ground starts the crop with a disease load that no spray will fully fix.
Raised beds help. A bed 20 to 30 centimetres above the path drains faster after rain, warms earlier in the cool months and makes weeding and harvesting easier on the back. Use a fork to break the bed up, mix in well-rotted compost, and shape the bed so the water runs off the edges rather than pooling on top.
The dry season gives you a free treatment called solarisation. Wet the bed thoroughly, cover it with clear polythene and bury the edges well, and leave it for four to six weeks in the hottest sunny weather. The heat under the film kills many soil pathogens and weed seeds. It does not replace a crop rotation, but it resets the bed before you plant. Plan it for the gap between harvests, so the bed is free when the seedlings are ready.
Poultry farmers have an easy source of organic matter here. Well-composted poultry litter, turned and aged until it no longer smells of ammonia, feeds the soil and supplies nitrogen. The rules for applying it are in our guide to using poultry manure as fertiliser, and the composting method is covered in our article on composting poultry litter. Fresh litter burns roots, so never put it straight onto a bed where seedlings are going in.
Feeding the crop: drip lines and simple fertigation
Greenhouse plants drink more than their field cousins, because the house cuts the rain and the leaves transpire steadily under the cover. A tomato bed on a hot day can lose more water than a farmer would guess from looking at it. Overwatering is the second-most common greenhouse mistake after heat, and it causes root rot and leaf diseases that look like something else entirely.
Drip lines are the simplest reliable answer. Run one line along each bed at the level of the emitters, check that the drippers are not blocked with sand from the water source, and install a filter at the tap. Water early in the morning and check the soil with a finger or a stick at the root zone before you water again. The soil should be moist, not wet and not dry on the surface.
Fertigation means feeding the nutrients through the same water. It saves labour and gives you better control, but it needs care. Mix fertiliser in a separate tank, dilute it according to the product label, and flush the lines with plain water after feeding so the emitters do not clog with salt. Keep a written feeding schedule and change it as the plants move from vegetative growth into flowering and fruiting, because they need different balances.
Test your water before you rely on it. Hard water or water with a high salt content builds up in the bed over a season and slowly stunts the crop. Ask the district agric office or the nearest soil testing laboratory how to take a sample.
Crops that suit a protected house in Ghana
Not every vegetable earns its place under cover. The best crops are the ones that the open field handles badly in the rains and that your nearest market pays for. Tomato tops the list in most markets, followed by sweet and hot peppers, cucumber, lettuce and the leafy greens that sell in the big urban markets.
Tomato needs a trellis or string support, pruning of side shoots and a steady feed of potassium once the fruit starts to set. It is the crop with the most to gain from protection, and the one that punishes the careless farmer hardest. Our article on growing tomato in Ghana covers the pests in detail, and the same whitefly and thrips problems come into the house with you.
Peppers take longer to start but reward patience. Sweet pepper sells well to hotels and supermarkets, and hot pepper finds a steady trade in the markets during festive weeks. Both need warm conditions and steady water.
Cucumber grows fast and tolerates heat better than lettuce, but it needs a strong trellis and frequent harvesting, because a cucumber left on the vine for two days becomes too big to sell. Lettuce and the leafy greens want cooler conditions and do best in the cooler months, in a tunnel or in shaded corners of a net house.
Okra and the African leafy vegetables also grow well under cover, and they suit farmers who sell to local food sellers rather than to big buyers. Start with one crop you already know, and add a second only after the first is running well.
Whitefly, thrips and the viruses they carry
In a protected house, the insect that matters most is not the one you can see. Whitefly and thrips are tiny, they breed quickly in warm air, and they carry viruses that wipe out a crop in weeks. Tomato yellow leaf curl virus travels on whitefly, and thrips spread tospoviruses that scar and kill plants. A single infected seedling brought in on a tray can start the problem.
Scout the crop twice a week. Turn over the youngest leaves, tap the plant over a white sheet of paper and count what falls out, and look at the underside of the leaves for silver scars that show thrips feeding. Yellow sticky traps near the entrance help you see the arrival of new insects. Record the counts. A rising trend tells you to act before the damage shows.
Control starts with the barrier. Net the vents and doors, dip or treat seedlings before they go in, and remove any plant that shows virus symptoms rather than hoping it recovers. Weeds inside and around the house harbour whitefly, so clear them from the paths and the strip outside the net.
When you need a spray, use a product that is registered for the crop and the pest in Ghana, check the label for the waiting period before harvest, and rotate the active ingredient so the insects do not build resistance. PPRSD, the MoFA directorate that regulates crop protection products, can confirm which ones are registered. Protective clothing, gloves and a mask are not optional, and the sprayer needs cleaning after every use. Follow your agric extension officer's advice for timing, because the right answer depends on the pest pressure in your area that week.
Red spider mite is the other pest that thrives in a hot, dry house. It causes bronzing on the leaves. Misting the air and the underside of the leaves in the late morning slows it down, and a sharp drop in humidity from over-ventilation makes it worse.
Need chicks for your next batch?
Send breed, number and town. We reply with price, hatch date and delivery cost in writing.
Pollination in a closed house
Tomato flowers carry both male and female parts, but the pollen sits inside the flower and needs a shake to fall onto the stigma. Outside, wind and insects do the job. Inside a closed house on a still morning, very little happens. Fruit set drops, and the farmer blames the variety or the feed when the cause is simply missing movement.
Gently tap the flower trusses or the wires that hold the plants each morning, once the flowers are open and dry. A battery-powered vibrator does the same job on a larger house. Many commercial growers use bumblebees for tomato pollination in Europe, but in Ghana the cost, the supply of colonies and the risk to the bees make hand shaking or a fan the practical choice for most farms. Check with the nearest extension office before you bring in any insect from outside.
Peppers set fruit more reliably than tomatoes, but they still benefit from air movement. Cucumber flowers are mostly male early on, and the female flowers set fruit with pollen from the same plant when the air moves. A fan on a timer, running for an hour or two in the morning, covers most of this.
Heat and pollination problems look alike from a distance. Both leave a plant full of flowers and few fruit. Measure the temperature inside first, then shake the flowers, and see which one changes the picture.
Planting around the festive markets
A greenhouse is only as good as its timing. Ghanaian consumers buy more tomato, pepper and fresh vegetables around Easter, at Christmas and during the two Eid festivals, and prices in the big markets move with those dates. A house that harvests in the middle of the glut earns less than the same crop harvested a fortnight earlier or later.
Count back from the date you want to sell. Tomato runs from transplant to first harvest in roughly two to three months, depending on the variety and the weather, and the harvest then continues for several weeks. Nursery work takes a further three to five weeks before transplanting. Plan the nursery as well as the crop, because a late nursery pushes the whole calendar back.
| Target sale | Start the nursery about | Transplant about | Notes |
|---|---|---|---|
| Easter | Late December to early January | Early to mid February | Dry-season heat, so shade and water are the limits |
| Eid al-Fitr | Depends on the moon, so check the date each year | About ten weeks before the day | Count back from the actual date, since it moves each year |
| Christmas | Late July to early August | Late August to September | Harvest runs into the harmattan, which is cool, so check the house temperature |
| Eid al-Adha | Depends on the moon, so check the date each year | About ten weeks before the day | Good time for peppers if your buyers are restaurants |
These are working estimates, not a guarantee. The exact dates depend on the variety, the zone and the weather that season, so check your own records from the last crop before you set the schedule.
Keep at least one bed in reserve each cycle for a second planting, in case the first one fails to heat, pests or a lost nursery. A reserve bed costs a little land and a few seeds, and it saves a whole season when something goes wrong.
Where a poultry keeper fits: manure, labour and risk
Farmers who start with day-old chicks often reach a point where they want a second enterprise that uses the same daily discipline. A greenhouse suits that position well. It uses the same daily discipline as a poultry house, with the same habits of early checks, clean water and a written record. It also sits alongside the birds, so the manure, the labour and the morning routine can be shared.
The risks are different, though, and they should be counted honestly. A greenhouse will not earn while the crop is being established. A bad season of whitefly can wipe out a planting in weeks, and a hot spell in March can cut the yield. Keep the birds and the vegetables on separate budgets so a crop failure does not drain the flock money.
Keep the greenhouse clean from the poultry house too. Wash your boots and tools before you walk from a bird pen into the crop, and keep the litter store away from the net house. The biosecurity steps that keep a flock safe also keep the greenhouse free of soil-borne disease. The steps in our biosecurity guide apply here too.
If you are thinking about starting a flock first, the chicks are the place to begin. You can order from our day-old chicks page, go straight to the order section, or message +233 24 915 1503 on WhatsApp. The poultry business plan guide helps you set the figures against each other, and whether a flock pays in Ghana is covered separately. If you are planning a larger joint project, the partnership page explains how we work with farms.
Keeping records that show whether the house pays
A greenhouse that does not keep records cannot tell you whether it is working. You will remember the big harvest and forget the three weeks of whitefly, and next season you will repeat the same mistake. A simple notebook, or a sheet on the phone, is enough if you use it every day.
Record the date of each planting, the variety and the source of the seed, the temperature at the morning and afternoon readings, the water and feed you added, every pest count and every spray with its product name and waiting period. At harvest, record the weight picked each day and the grade. At the end of the cycle, add the costs you paid and the sales you made, and work out the cost per kilogram of marketable crop.
- Write the planting date, variety and seed source on the bed label.
- Read and record the temperature twice a day.
- Log every pest count from scouting, with the date.
- Note every spray and feed with the product, rate and waiting period.
- Weigh the harvest by day and grade it by hand.
- Total the costs and the sales at the end of the cycle.
The same habit works across your farm. Our guide to poultry record keeping shows how to set up a single book for the flock and the crops, so you can see what each enterprise is costing you.
Checklist before you build
Use this list before you sign for the structure. If you cannot tick a line, sort it out first, because a greenhouse on the wrong site is expensive to move.
- Site has shade from trees in the afternoon, not from the house itself.
- Ground drains after heavy rain and does not pool in the corner.
- Water source is within easy reach, tested, and has a working filter.
- Power supply is known, and a backup plan exists for the fan or pump.
- Structure has side or end vents that open wide, and the supplier has confirmed the mesh size.
- A thermometer is installed inside the house and read every morning.
- Soil is solarised or replaced, and the beds are raised.
- Seedlings come from a clean source, and the nursery is separate from the house.
- A scouting routine and a spray record are in place before the first planting.
- The market, buyer and delivery route are known before the transplant date.
Ask your district agric office and the nearest MoFA extension officer to walk the site with you. They can check the soil, the water and the pest pressure in your zone at no cost, and they will tell you which crops are doing well in your district this season.
Questions farmers ask
Is a greenhouse worth it for a small farm in Ghana?
It can be, if the site is right and you have a buyer lined up before the first transplant. A net house on a plot with shade, water and drainage is the easiest place to start. Count the costs of the structure, the water, the nets and the labour against the sales you expect, and check current market rates in your town rather than relying on figures from another region.
Which is better for beginners, a net house or a polythene tunnel?
A net house is usually the easier start in the south and middle belt, because the air moves freely and the crop is protected from whitefly and thrips. A tunnel holds rain off the leaves, which helps in the wet months, but it heats up fast. Many farmers choose a net house first and add a tunnel for the rainy-season crop later.
How do I stop whitefly from destroying my tomatoes under cover?
Net every opening, treat or inspect seedlings before they go in, clear weeds from the paths and the strip outside, and scout the crop twice a week. Remove any plant with virus symptoms. If you spray, use a product registered for the crop in Ghana, follow the label, and check the waiting period before harvest. Your agric extension officer can advise on timing.
Can I use poultry manure in the greenhouse soil?
Yes, once it is well composted. Fresh litter is too hot and too high in ammonia, and it burns young roots. Compost it until it no longer smells strongly, let it rest, then mix it into the bed a few weeks before planting. Our guide to using poultry manure as fertiliser gives the steps in more detail.
Why are my tomato flowers falling off without setting fruit?
The most common causes are very high temperatures inside the house, poor air movement and pollen that does not shed. Check the thermometer, open the vents, and gently shake the flower trusses each morning once the flowers are dry. If the problem continues after those steps, ask an extension officer to look at the plants.
How long does it take to get a return from a protected house?
A tomato crop usually takes two to three months from transplant to first harvest, and the harvest then runs for several weeks. The first full cycle includes the nursery, the soil preparation and the learning curve, so most farmers judge the house over at least two cycles. Keep records from the first planting so you can see the trend.
Do I need electricity for a greenhouse?
Not always. A net house with good vents and a drip line fed from a raised tank can run without power, although a fan helps in the hottest months. If you add a pump or fans, plan for the outages common in your area and think about a battery or a generator for the critical hours.
