Divisi
When to plant Onion in Nyanza-Lac
Makamba, Burundi
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 Oct 2026 – 19 Feb 2027 opens in 1 week | 18 Sep 2026 – 20 Jul 2027 |
| Expected harvest | about 26.3 t/ha | about 39.5 t/ha |
| Harvest | From 8 Jan 2027 to 19 Jun 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 Jan 2027. That is the point in the window where the rains are most reliably established.
This season's outlook for Nyanza-Lac leans wet. Plant at the early end of the window, and make sure water can drain off the field — a wet year does more damage through waterlogging than through the rain itself.
Planting after 19 Feb 2027 leaves the crop short of season: it runs into the dry months before it has finished filling.
What decides this in Nyanza-Lac
| Rain and temperature | 96% |
|---|---|
| The soil | 76% |
| The lie of the land | 76% |
For onion in Nyanza-Lac, 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 2026/27 season in Nyanza-Lac
| Rainy seasons | One each year — one chance to plant, so timing carries it |
|---|---|
| When the rains are expected | October 2026 to June 2027 |
| Rain in a typical year | About 1,015 mm |
| This season's rain | Leaning wet — January, October, November and December look heavier than usual. Make sure water can drain off the field; a wet year does more damage through waterlogging and disease than through the rain itself. |
| This season's heat | Hotter than usual — about +1.0 °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 | 4 kinds of ground. The season below is the largest that farms — about 52% of this area. |
| 52% | enough rain for one full main crop; warm all year, so nothing but rain ends the season 263 growing days · about 1,030 mm · October to June |
|---|---|
| 27% | enough rain for a long crop, or two in a year; warm all year, so nothing but rain ends the season 276 growing days · about 1,150 mm · September to June |
| 9% | enough rain for a long crop, or two in a year; warm all year, so nothing but rain ends the season 278 growing days · about 1,230 mm · September to June |
| 6% | enough rain for a long crop, or two in a year; warm all year, so nothing but rain ends the season 273 growing days · about 1,180 mm · September to June |
last updated 16 September 2026
Frost and pest pressure hold back about 15% 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 Nyanza-Lac
| Planting material | About 500,000 plants per hectare |
|---|---|
| Nitrogen (N) | About 47 kg per hectare |
| Phosphate (P₂O₅) | About 9 kg per hectare |
| Potash (K₂O) | About 53 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 Nyanza-Lac 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.
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 Nyanza-Lac?
Nyanza-Lac rates as favourable for onion.
When should I plant onion in Nyanza-Lac?
Typically 10 Oct 2026 to 19 Feb 2027, forecast-adjusted.
Is this exact for my own field?
No — these are readings taken across Nyanza-Lac, not on your field. Soil, slope and rainfall change from one farm to the next. Check your own location to see your own numbers.
