Divisi
When to plant Onion in Grootfontein
Otjozondjupa, Namibia
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 | 2 Jan 2027 – 1 Feb 2027 opens in 13 weeks | 21 Jan 2027 – 20 Jul 2027 |
| Expected harvest | about 18.4 t/ha | about 41.7 t/ha |
| Harvest | From 2 Apr 2027 to 1 Jun 2027, depending on the planting date | |
| Ready to harvest | 90–120 days after planting | |
| Rain meets its needs | 69% | |
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 12 Jan 2027. That is the point in the window where the rains are most reliably established.
This season's rainfall outlook for Grootfontein 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 1 Feb 2027 leaves the crop short of season: it runs into the dry months before it has finished filling.
What decides this in Grootfontein
| Rain and temperature | 96% |
|---|---|
| The soil | 76% |
| The lie of the land | 88% |
For onion in Grootfontein, 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 Grootfontein
| Rainy seasons | One each year — one chance to plant, so timing carries it |
|---|---|
| When the rains are expected | December 2026 to April 2027 |
| Rain in a typical year | About 508 mm |
| This season's rain | Leaning dry — January, February and December 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 +1.9 °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 short crop, and only if timed to it, warm all year, so nothing but rain ends the season |
| Ground this covers | 2 kinds of ground. The season below is the largest that farms — about 95% of this area. |
| 95% | enough rain for one short crop, and only if timed to it; warm all year, so nothing but rain ends the season 118 growing days · about 510 mm · December to April |
|---|---|
| 4% | enough rain for one short crop, and only if timed to it; warm all year, so nothing but rain ends the season 136 growing days · about 580 mm · November to April |
last updated 17 September 2026
Limited water holds back about 35% 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 Grootfontein
| Planting material | About 500,000 plants per hectare |
|---|---|
| Nitrogen (N) | About 33 kg per hectare |
| Phosphate (P₂O₅) | About 6 kg per hectare |
| Potash (K₂O) | About 37 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 Grootfontein 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 Grootfontein?
Grootfontein rates as favourable for onion.
When should I plant onion in Grootfontein?
Typically 2 Jan 2027 to 1 Feb 2027, forecast-adjusted.
Is this exact for my own field?
No — these are readings taken across Grootfontein, not on your field. Soil, slope and rainfall change from one farm to the next. Check your own location to see your own numbers.
