Divisi
When to plant Roselle in Toamasina I
Atsinanana, Madagascar
Roselle — you may know it as bissap, zobo, karkade or sorrel — is a tall, warm-season hibiscus grown for the fleshy red cups (the calyces) that swell at the base of each flower once the petals drop.
| Fit | Favourable |
|---|---|
| When to plant | 21 Jan 2026 – 1 Jan 2027 open now |
| Expected harvest | about 1.2 t/ha |
| Harvest | From 21 May 2026 to 30 Jun 2027, depending on the planting date |
| Ready to harvest | 120–180 days after planting |
| Work it takes | 85–175 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 1 Jan 2027. That is the point in the window where the rains are most reliably established.
This season's rainfall outlook for Toamasina I 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 Jan 2027 leaves the crop short of season: it runs into the dry months before it has finished filling.
What decides this in Toamasina I
| Rain and temperature | 96% |
|---|---|
| The soil | 96% |
| The lie of the land | 96% |
For roselle in Toamasina I, rain and temperature is the tightest of the three at 96%. This one is fixed. It is why the planting window above is where it is — hitting those dates is the whole of your control here.
The 2025 season in Toamasina I
| When the rains are expected | January 2025 to December 2025 |
|---|---|
| Rain in a typical year | About 2,458 mm |
| This season's rain | Leaning dry — January and February 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 +1.1 °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 a long crop, or two in a year, 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 80% of this area. |
| 80% | enough rain for a long crop, or two in a year; warm all year, so nothing but rain ends the season 365 growing days · about 2,500 mm · January to December |
|---|---|
| 20% | enough rain for a long crop, or two in a year; warm all year, so nothing but rain ends the season 365 growing days · about 2,400 mm · January to December |
last updated 17 September 2026
Frost and pest pressure hold back about 15% of yield here.
What roselle needs to grow here
| Soil it likes | well-drained sandy loam or loam soil |
|---|---|
| Soil sourness (pH) | Happiest between pH 5.5 and 7.5 |
| Spacing | 80 cm between rows, 60 cm between plants |
| Feed it most with | nitrogen, phosphorus and potassium |
What it takes to grow roselle in Toamasina I
| Nitrogen (N) | About 48 kg per hectare |
|---|---|
| Phosphate (P₂O₅) | About 18 kg per hectare |
| Potash (K₂O) | About 66 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 | 85–175 days per hectare, by hand |
These are the nutrients a roselle 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 Roselle with a plan, not a guess
Everything above describes Toamasina I 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.
Roselle 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 roselle grow well in Toamasina I?
Toamasina I rates as favourable for roselle.
When should I plant roselle in Toamasina I?
Typically 21 Jan 2026 to 1 Jan 2027, forecast-adjusted.
Is this exact for my own field?
No — these are readings taken across Toamasina I, not on your field. Soil, slope and rainfall change from one farm to the next. Check your own location to see your own numbers.
