Divisi
When to plant Irish potato in Rukwa
United Republic of Tanzania
Known here as viazi mviringo · kiazi
The Irish potato (mbatatisi, ikirayi, viazi mviringo) is a cool-weather crop grown for the tubers that swell underground — it is not a grain, and it is not the same plant as sweet potato.
| Measure | Rain-fed | With irrigation |
|---|---|---|
| Fit | Favourable | |
| When to plant | 22 Oct 2026 – 9 Feb 2027 opens in 3 weeks | 21 Jan 2026 – 1 Jan 2027 |
| Expected harvest | about 30.7 t/ha | about 39.5 t/ha |
| Harvest | From 31 Dec 2026 to 19 Jun 2027, depending on the planting date | |
| Ready to harvest | 70–130 days after planting | |
| Work it takes | 110–185 days per hectare, by hand | |
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 10 Jan 2027. That is the point in the window where the rains are most reliably established.
This season's outlook for Rukwa 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 9 Feb 2027 leaves the crop short of season: it runs into the dry months before it has finished filling.
What decides this in Rukwa
| Rain and temperature | 96% |
|---|---|
| The soil | 76% |
| The lie of the land | 76% |
For irish potato in Rukwa, 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 Rukwa
| Rainy seasons | One each year — one chance to plant, so timing carries it |
|---|---|
| When the rains are expected | October 2026 to May 2027 |
| Rain in a typical year | About 950 mm in a typical farming district |
| Across its districts | From about 743 mm in the driest of 4 districts to about 950 mm in the wettest |
| This season's rain | Leaning wet — January, 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 | 3 kinds of ground. The season below is one typical farming district's, not a figure for the whole of this area. |
| 58% | enough rain for one full main crop; warm all year, so nothing but rain ends the season 208 growing days · about 890 mm · October to May |
|---|---|
| 37% | enough rain for one full main crop; warm all year, so nothing but rain ends the season 206 growing days · about 860 mm · October to May |
| 4% | enough rain for one short crop, and only if timed to it; warm all year, so nothing but rain ends the season 175 growing days · about 790 mm · October to April |
last updated 17 September 2026 · from all 4 areas within it
Frost and pest pressure hold back about 15% of yield here.
What irish potato needs to grow here
| Soil it likes | well-drained loam or sandy loam soil |
|---|---|
| Soil sourness (pH) | Happiest between pH 5.0 and 6.5 |
| Spacing | 75 cm between rows, 28 cm between plants |
| Feed it most with | potassium and magnesium |
What it takes to grow irish potato in Rukwa
| Planting material | About 47,000 plants per hectare |
|---|---|
| Nitrogen (N) | About 101 kg per hectare |
| Phosphate (P₂O₅) | About 31 kg per hectare |
| Potash (K₂O) | About 178 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. |
| Hand work | 110–185 days per hectare, by hand |
These are the nutrients a irish potato 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 Irish potato with a plan, not a guess
Everything above describes Rukwa 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.
Irish potato 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 irish potato grow well in Rukwa?
Rukwa rates as favourable for irish potato.
When should I plant irish potato in Rukwa?
Typically 22 Oct 2026 to 9 Feb 2027, forecast-adjusted.
Is this exact for my own field?
No — these are readings taken across Rukwa, not on your field. Soil, slope and rainfall change from one farm to the next. Check your own location to see your own numbers.
