Short answer: Cold storage holds fresh produce at a steadier temperature and humidity than a room or a table, which slows ripening, rot and weight loss. Not every crop wants the cold, though: tomatoes, onions and yams each need something different. Pick the store by the crop, the power you actually have and the weeks you need to hold stock, then cost it per crate held per day.
Key takeaways
- Match the store to the crop, because chilling some tropical produce damages it rather than helping.
- Plan the power supply first, including what happens during dumsor, and know how many hours of cut the store can carry.
- Cool produce quickly after harvest, since the field heat in a crate is the first thing a store has to remove.
- Keep a daily temperature and humidity record, which doubles as proof for a buyer.
- Size the store for the peak week, not the average week, and compare options by cost per crate held per day.
Why the tomatoes went soft before the lorry came
It is ten in the morning at a farm near Ejisu, and the tomatoes picked at dawn are already sitting in crates in the sun. The lorry was due at eight. Now it is due after lunch, and by the time it arrives the fruit that looked firm will have a soft shoulder and a sour smell in the crate. Some of the crop will go to the market women at half price. Some will go on the compost heap.
That is the problem cold storage is meant to solve. Fresh produce keeps respiring after it is picked. Heat speeds that up, and so do dry air and bruising. A store that cools the crop, holds the humidity right and keeps the air moving buys a farm days, sometimes weeks, of extra selling time. That time is only worth paying for if the store costs less than the loss it prevents, so the sums matter. Losses that start in the field, before the crop reaches any store, are covered in our post-harvest losses guide.
Cold does different things to different crops
Cold is not a single setting. Some crops keep well at low temperatures, some are damaged by them, and some need a cool, humid store with fresh air moving through it. Unripe tomatoes that are chilled may ripen unevenly, while ripe tomatoes last longer when they are cool. Leafy greens need cold and high humidity. Yams and many root crops need a cool, dry, ventilated place rather than a refrigerated room. Mango and pineapple can suffer chill damage if they are held too cold for too long.
Check the storage guide for your exact crop and variety, and ask your extension officer for advice for your zone. The table gives the broad picture only, to help you decide what to ask.
| Crop | Broad storage need | Main risk if handled wrongly |
|---|---|---|
| Ripe tomatoes | Cool, not cold, with moderate to high humidity | Softening, water loss, mould |
| Unripe tomatoes | A warmer ripening room with moderate cooling | Chill damage, uneven colour |
| Leafy greens | Cold and humid, cooled quickly after picking | Wilting, yellowing, slime |
| Peppers, sweet and hot | Cool, with good airflow | Shrivelling, rot at the stalk end |
| Onions and garlic | Cool, dry, ventilated, low humidity | Sprouting and rot in damp air |
| Mango and pineapple | Cool, but not too cold for too long | Chill injury, uneven ripening |
| Yam | Cool, dry, shaded and ventilated | Sprouting, rot, weight loss |
The options, from a shaded room to a refrigerated cold room
Four broad options suit most Ghanaian farms, with very different costs and power needs.
- Ventilated shade store. A roofed, shaded, well-ventilated room with slatted shelves. It costs little, needs no power, and suits yams, onions and dried produce. It does not cool fresh fruit or greens.
- Evaporative cool chamber. A double-walled brick or block chamber with a sand or sawdust gap that is kept wet. Evaporation cools the inner space without electricity. Designs of this kind are used in several West African countries, and they suit tomatoes, leafy vegetables and peppers in dry air. They work less well in humid rainy-season weather, and they need water every day.
- Refrigerated cold room. An insulated room with a compressor that holds a set temperature and can reach the cold that leafy crops need. It works well when the power is reliable or backed by a generator or solar system, and it carries the highest power bill.
- Insulated boxes and ice for transport. Not a store, but a way to keep a load cool between the farm and the buyer. It is often the cheapest step to add first.
Get quotes from two builders or suppliers for each option you consider, with the same specification, and write down the date. Ask for the power draw, the service interval and how long the warranty runs.
Power: the bill, the generator and dumsor
The power bill decides whether a cold room is worth running. A compressor store uses electricity day and night, so the monthly cost depends on the size of the room and how hot it gets outside. Ask the supplier for the daily consumption in kilowatt-hours, then take that figure to your electricity provider's current tariff. Do not guess. Put the figures on your cost sheet. Keep the power bill in the same cash book as every other cost on the farm, using the method in our farm record-keeping guide.
Dumsor is the local word for power cuts, and any store that depends on the grid needs a plan for them. A generator is the usual answer, but it needs fuel stored safely, regular servicing and someone on hand. A solar system with batteries can run the compressor for some hours, but it costs more up front, and battery replacement belongs in your numbers. Decide how many hours of cut you can carry, then check the temperature log after the last cut you had. If no cut has ever been logged, you do not yet know your risk.
Humidity counts as much as temperature
Most farmers think of cold storage as a thermometer problem. For many crops it is a humidity problem too. Dry air pulls water out of leafy greens and fruit, so they wilt and shrink, and that weight loss is money you have already grown. Damp air does the opposite job: it encourages rot and mould on onions and yams.
A cheap hygrometer beside the thermometer tells you which problem you have. If the store is too dry for leafy greens, wet the floor, hang damp sacks or set out a water tray, then check the effect the next morning. If it is too damp for onions, improve the air movement, lift the crates off the floor and remove any spoiled item at once. Humidity changes with the season, and a store that works in the dry harmattan can fail in the rainy months.
Size the store for the busiest week, not the average week
A store sized for the average week sits half empty for most of the year and then overflows at Christmas, Easter or Eid. Work out your peak. Look at the weeks when buyers ask for the most: the festive run for tomatoes and peppers before Christmas, Easter cooking, and the Eid al-Adha period when households buy for celebrations. Count the crates or kilograms you would want to hold in the peak week, and add a margin for a glut.
Keep a simple record of crates in and crates out for two seasons if you can. It shows when the store is full, when it is empty and what the quiet months are good for. They may be the time to service the cooling kit, run a dry-produce crop, or hold a different product in the same space. A glut that the store cannot hold can be turned into paste or dried product instead, as our agro-processing and value addition guide explains.
Pre-cooling and loading without warming the room
A crop picked at noon and left in the sun carries a lot of field heat. If that heat goes into a cold room, the compressor works hard to remove it, and the crates near the door warm the rest. Cool the produce first. Pick in the early morning, put the crates in shade straight away, and move them into the store as soon as the first crates are ready, rather than waiting to fill a whole lorry.
Load with airflow in mind. Leave a gap between the crates and the wall, do not stack past the height the shelves allow, and never block the vents. Put the newest crop at the back and the oldest at the door, so the oldest goes out first. Keep the door shut between loadings.
Temperature records a buyer can read
A buyer who has been caught out by a warm load will ask what temperature the store kept. A written daily record answers that question in a way a promise cannot. Put a minimum-maximum thermometer, or a simple data logger if your budget allows, in the store at crate height rather than by the door. Read it at the same times each morning and evening, and write the highest and lowest readings and the humidity, with the date, your initials and the power status.
| Date | Time | Min temp | Max temp | Humidity | Power status | Action taken |
|---|---|---|---|---|---|---|
| Write the date | Morning or evening | Lowest reading | Highest reading | Reading from the hygrometer | On grid, generator or cut | What you did, if anything |
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Cleanliness, pests and the store that smells
A cold room that smells damp is telling you something. Wipe the shelves and floor each week, remove spoiled produce the day you see it, and never leave a rotten crate inside to infect the stack beside it. Keep chemicals, fuel and fertiliser out of the store, because produce takes up smells quickly.
Rats find cold stores as attractive as any other building. Seal door gaps and pipe holes, keep the floor clear and check the outside for burrows. Ants and flies follow spilled sugary fruit and damp floors, so clean up each time you load. Write a weekly cleaning sign-off on the store door, so the job is visible and shared.
Keeping the chain cool on the road and at the market
A cold store that protects the crop until the farm gate only covers the first part of its route. The rest needs the same care. Use insulated boxes, ice packs or a covered cool box, and keep the lorry shaded. Plan the run so the load reaches the buyer's store, not a stall in the sun, inside the time the crop can take.
At the market, a shaded stall with a cool box beats an open table. Put the most perishable produce in the cooler and sell it first. Bring unsold stock back to the store rather than leaving it out overnight, and record what came back, so you know the true cost of the market wait.
Costing a store per crate held per day
Cost each option per crate held per day, so that a small cool chamber and a cold room can be compared on the same basis. Add the capital cost spread over the years you expect the store to last, the monthly power or fuel cost, the water for an evaporative chamber, the labour to run it, the maintenance and the spoilage you still expect. Divide the monthly total by the number of crate-days you will hold, and you have a figure you can compare across options.
Every number on that sheet needs a source and a date. Use written quotes from builders and suppliers, your electricity tariff and your own crate records. Leave the crop's market price out of the store calculation and add it only to your sales sheet, checked against your local market on more than one day. The store is worth building when its cost per crate-day is lower than the value it saves, at a loss rate you have measured yourself. Once the costs are dated and checked, put the store into the budget of your plan, as our guide to writing an agribusiness plan describes.
Poultry farms face the same sum with eggs and dressed birds. Our guides to cold rooms and freezers for poultry and storing table eggs use the same method, and you can reuse it for produce.
Checklist before you fill a cold store
- Each crop you plan to store has a written storage guide, checked for your variety and zone.
- The power supply is described, including the longest cut the store can carry.
- The store has a thermometer and hygrometer at crate height, and a daily record sheet.
- Produce is cooled after picking and moved into the store the same day.
- The peak week is calculated, with a margin for a glut.
- Shelves and crates allow airflow, and a first-in, first-out rule is posted on the door.
- Rats, ants and damp are addressed, with a named person for the weekly clean.
- Cost per crate-day is calculated from dated quotes and a loss rate you have measured.
- The road plan keeps the load cool between the store and the buyer.
If poultry is part of the same farm, the egg and dressed-bird stores can share the power plan and the temperature log. Our guide to dressing and selling chicken covers the cold chain for birds. For day-old chicks to start a flock beside the produce, see our day-old chicks page and order through the order form, or message +233 24 915 1503 on WhatsApp. For supply talks beyond a single flock, our partner with us page is the place to start. Chick prices are on our prices page.
Questions farmers ask
Do all farm crops need a cold room?
No. Many tropical crops are damaged by cold, and yams, onions and dried produce keep well in a shaded, ventilated store without any power. A cold room suits leafy greens and some fruit, but only when the buyer and the price justify the running cost. Start with the crop you lose most, read the storage guide for that crop and then choose the store.
Is an evaporative cool chamber really cooler than the air outside?
It can lower the inside temperature noticeably in dry air, which helps tomatoes, peppers and leafy vegetables. It works less well in humid weather because the water evaporates more slowly. It needs a daily water supply and a shaded site. Measure inside and outside temperatures for a week in your own season before you rely on it for a sale.
How much power does a cold room use?
It depends on the size of the room, how well it is insulated, the outside temperature and how often the door opens. Ask the supplier for the daily consumption figure for your room size, then multiply by your electricity provider's current tariff. Do not rely on a generic figure from a brochure. Your own temperature and power log will give you the figures for your site.
What do I do when the power is off for hours?
Know the longest cut you can carry before the store warms past its safe range. Keep the door shut, cover the crates with insulating sheets and use ice or a generator if you have them. Log the temperature through the cut and afterwards, so you know whether the crop was affected. Plan a backup for any crop you cannot afford to lose.
How long can I hold tomatoes in a cool store?
It depends on the ripeness at picking, the variety, the temperature and the humidity. Fruit picked ripe holds for a much shorter time than fruit picked at the colour stage. Use the storage guide for your variety, check the crop every day and sell the oldest first. Keep a written record for each lot, so that you learn your own time limits instead of relying on a general rule.
Can I share a cold store with other farmers?
Yes, many farms do. A shared store works when the owners agree on booking, cleaning, power costs, access hours and what happens if the power fails. Write those rules down before the first load and keep a log of who put what in. Be careful with mixed crops, since one farmer's rot can spread to another's crates if the store is not kept clean.
Where can I get advice before building a store?
Talk to your district MoFA office and agric extension officer about the crops and the local power and water situation. Ask builders and equipment suppliers for written quotes against the same specification. Check the current terms of any support programme before you plan around it. A visit to an existing store in your area is often the most useful step of all.
