Divisi
When to plant Onion in Benin
Onion is a cool-season vegetable you grow for its bulb — the swollen base of the leaves — but across sub-Saharan Africa it is most often grown as an irrigated hot dry-season crop, and it stands real heat (up to about 42 °C) as long as the water never stops.
| Measure | Rain-fed | With irrigation |
|---|---|---|
| Fit | Favourable | |
| When to plant | 10 Apr 2027 – 29 Jul 2027 opens in 27 weeks | 2 Mar 2026 – 17 Nov 2026 |
| Expected harvest | about 20.8 t/ha | about 29.6 t/ha |
| Harvest | From 9 Jul 2027 to 26 Nov 2027, depending on the planting date | |
| Ready to harvest | 90–120 days after planting | |
Rain-fed. These dates are worked out from each place's own rainfall, for a field watered by the season — with irrigation a window can open earlier, close later, or come round more than once a year. Check your own field under What grows, or get the Divisi app for a calendar dated to your farm.
If you only get one chance to plant, aim for around 2 May 2027. That is the point in the window where the rains are most reliably established.
This season's rainfall outlook for Benin leans dry, so these dates sit later than the long-run average. Planting on the date you are used to risks germinating into a false start and having to replant.
Planting after 29 Jul 2027 leaves the crop short of season: it runs into the dry months before it has finished filling.
What decides this in Benin
| Rain and temperature | 88% |
|---|---|
| The soil | 76% |
| The lie of the land | 88% |
For onion in Benin, the soil is the tightest of the three at 76%. This is the one you can actually move. Lime raises a sour soil, manure and compost lift what it holds, and both work within a season or two — money spent here changes the answer.
The 2027 season in Benin
| Rainy seasons | One each year — one chance to plant, so timing carries it |
|---|---|
| When the rains are expected | March 2027 to November 2027 |
| Rain in a typical year | About 900 mm in a typical farming district |
| Across its districts | From about 686 mm in the driest of 77 districts to about 1,183 mm in the wettest |
| This season's rain | Leaning dry — September and October look short of rain. Plant at the early end of the window, favour quicker and more drought-tolerant crops, and keep moisture in the soil: mulch, and weed early. |
| This season's heat | Hotter than usual — about +0.6 °C over the growing months. Heat makes the same rain do less, so a dry spell bites sooner: do not plant late, and shade or mulch what you can. |
| What that supports | enough rain for one full main crop, warm all year, so nothing but rain ends the season |
| Ground this covers | 2 kinds of ground. The season below is one typical farming district's, not a figure for the whole of this area. |
| 70% | enough rain for one full main crop; warm all year, so nothing but rain ends the season 233 growing days · about 1,050 mm · April to November |
|---|---|
| 27% | enough rain for one short crop, and only if timed to it; warm all year, so nothing but rain ends the season 169 growing days · about 920 mm · May to October |
last updated 30 September 2026 · from all 77 areas within it
Temperature holds back about 25% of yield here.
What onion needs to grow here
| Soil it likes | well-drained sandy loam or loam soil |
|---|---|
| Soil sourness (pH) | Happiest between pH 6.0 and 7.0 |
| Spacing | 20 cm between rows, 7 cm between plants |
| Feed it most with | nitrogen, potassium and sulphur |
What it takes to grow onion in Benin
| Planting material | About 500,000 plants per hectare |
|---|---|
| Nitrogen (N) | About 37 kg per hectare |
| Phosphate (P₂O₅) | About 7 kg per hectare |
| Potash (K₂O) | About 42 kg per hectare |
| In the shops | A basal compound at planting — Compound D, or an NPK blend — covers the phosphate and potash. A nitrogen top dressing — urea or AN — goes on once the crop is established. |
These are the nutrients a onion crop of that size carries off the field. What you actually apply depends on what your soil already holds — which is what a soil test, or the app's field records, tell you.
What to watch for
Grow Onion with a plan, not a guess
Everything above describes Benin as a whole — your own soil, slope and rainfall will shift the dates. The Divisi app works them out for your field, and dates each job that follows.
Where to sell Onion nearby
Onion in nearby districts
This calendar moves
Planting windows shift with the forecast. Leave your email and we'll send what changed, and a note when planting time nears — a couple of emails a month at most.
Frequently asked questions
Will onion grow well in Benin?
Benin rates as favourable for onion.
When should I plant onion in Benin?
Typically 10 Apr 2027 to 29 Jul 2027, forecast-adjusted.
Is this exact for my own field?
No — these are readings taken across Benin, not on your field. Soil, slope and rainfall change from one farm to the next. Check your own location to see your own numbers.
