Per the crop database: needs warm summer, small red bean, popular in East Asian cooking. Adzuki bean (Vigna angularis) is strongly self-pollinating, so isolation for pure seed is minimal, and although it shares its genus with mung bean and cowpea, all three are separate species that genuinely do not cross-pollinate with each other. Like other legumes, it fixes its own nitrogen as it grows.
Water need
Water matters most while pods are filling out -- even moisture through that stage has the biggest single effect on final yield.
Calories at a glance
3,290 kcal/kg dried -- in the same league as wheat and the site's other dried pulses (scale is log-based across all 55 crops in the calculator).
Temperature Range by Month
Month on the bottom, temperature up the side. The pale green background is what the plant can survive at all -- fatal above or below it, labelled directly on the chart where that applies to your zone. The coral band is its ideal range, and only fades in during the months this zone would actually have the crop in the ground -- reusing the exact same sowing/harvesting data as the calendar further down the page. The blue line is real monthly climate data (not a modelled estimate) for a representative rural/agricultural location in this zone -- a small farming town or agricultural research station rather than a major city, to avoid the warmer bias city weather stations have. For the actual verdict on how well this crop does in your zone, see the badge at the top of the page -- that's based on the site's own researched yield figures, not this chart.
Quick Start: Sowing to Storage
- Sow direct once soil is warm. Sow direct once the soil has genuinely warmed up -- adzuki bean is frost-tender and germinates poorly in cold, wet ground.
- Give it a genuinely warm summer. Adzuki bean needs sustained warmth through the growing season, per the crop database's own description, more than most other legumes on this site.
- Water evenly while pods are filling. Water matters most while pods are filling out -- even moisture here has the biggest effect on final yield.
- Leave pods on the plant to dry fully. For dried storage, don't pick pods young -- leave them on the plant until they rattle and have turned brown and papery.
- Shell and finish drying indoors. Shell the dried pods and spread the small red beans out somewhere warm and airy for a final week of drying before storing in an airtight container.
Sowing & Harvesting Calendar
Pick your zone under "Temperature Range by Month" above and this updates too. Boreal and Alpine show no window at all, since this site's own yield data marks adzuki bean as not viable in either.
Calories & Yield
Adzuki bean is a genuine calorie staple when dried at 3,290 kcal per kg -- in the same league as wheat. Tropical gives the best yield here.
| Climate Zone | Yield per plant | Calories per plant | Viability |
|---|---|---|---|
| Tropical / Humid | 2.0 kg | 6580 kcal | Viable -- best yield |
| Subtropical | 1.8 kg | 5922 kcal | Viable |
| Mediterranean | 1.8 kg | 5922 kcal | Viable |
| Temperate Maritime | 0.6 kg | 1974 kcal | Challenging (60% yield) |
| Temperate Continental | 0.9 kg | 2961 kcal | Challenging (60% yield) |
| Cool / Boreal | -- | -- | Not viable |
| Arid / Semi-Arid | 0.72 kg | 2368.8 kcal | Challenging (60% yield) |
| Highland / Alpine | -- | -- | Not viable |
Figures per plant sown, dried weight, from the site's own crop database. Maritime, Continental and Arid already reflect the 60% penalty applied to challenging zones.
Varieties Worth Knowing
Adzuki bean varieties mainly differ in earliness. Both below are open-pollinated (OP), meaning seed saved from them breeds true and is worth keeping under this site's seed-saving approach; neither is an F1 hybrid.
Seed Saving -- Quick Guide
Adzuki is a self-pollinating Vigna species with very low crossing risk -- and it doesn't cross with mung bean, black gram or moth bean either, despite the shared genus. Each is its own species.
SERVINGS, NOT DAILY CALORIES This works out plate-sized servings of adzuki bean from your seed during its fresh harvest window only, not your group's full daily calorie needs. For that, use the main calculator.
Estimated for your selected zone above, using this site's own germination, loss and yield figures for adzuki bean -- a helping is roughly what you'd put on a plate as part of a meal with other veg. Treat it as a planning estimate, not a promise.
Storage & Preservation
Adzuki bean is grown here specifically for dried storage -- pods left on the plant until fully dry, then shelled and given a final week of airing indoors before going into an airtight container.
Stored this way in a cool, dry place, dried adzuki beans keep for a genuinely long time -- years rather than months, the same storage league as wheat, oats and this site's other dried staples.
Growing Adzuki Beans Without Bought Inputs
Bean beetles and aphids are the main pests to watch for, along with slugs on young seedlings.
Rotating away from the same ground each year and hand-picking pests off the plants are simple, genuinely effective input-free measures.
Adzuki bean fixes its own nitrogen via bacteria in root nodules, genuinely improving the soil for whatever's grown there next -- factor that into a wider rotation plan, not just a calorie one.
Frequently Asked Questions
Does adzuki bean cross-pollinate with mung bean or cowpea?
No -- adzuki bean, mung bean and cowpea all belong to the same genus, Vigna, but they're distinct species and do not cross with each other despite that genus-level relatedness. That's a different situation from the common bean cluster elsewhere on this site (Borlotti, Haricot and French bean), which genuinely is one shared species.
Is adzuki bean genuinely a small red bean?
Yes -- per the crop database's own description, it's a small red bean, popular in East Asian cooking, distinctive enough in size and colour to be easy to tell apart from the other dried pulses on this site once shelled.
Why isn't adzuki bean viable in Boreal or Alpine zones on this site?
It's a genuine warm-season crop that needs a real summer to fill its pods, and it's frost-tender at both ends of the season -- exactly the combination that a short, cool Boreal or Alpine growing season can't provide.