Broad bean is nominally self-pollinating, but don't let that fool you into skipping isolation -- it's heavily bee-visited in practice, with documented outcrossing as high as 60% depending on variety and conditions. That makes it behave more like an allium than like most other legumes on this site. Grown for drying rather than fresh eating, it's also a genuine cool-season specialist: heat above roughly 27°C sterilises the flowers outright, and it fixes its own nitrogen while it grows.
Water need
Reasonably drought-tolerant once established, but even moisture while flowering and podding improves the set.
Calories at a glance
3,410 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 Drying
- Sow direct. Sow seed direct where it's going to grow -- broad bean's long taproot resents disturbance, so it doesn't transplant well. Overwinter sowing is possible in mild zones for an earlier, hardier crop.
- Support taller varieties. Tall broad bean varieties benefit from a simple stake-and-string support to stop them toppling once heavy with pods; dwarf varieties usually don't need it.
- Pinch out tops once pods have set. Removing the soft growing tip once the lowest pods have set diverts energy into pod-filling and removes the part of the plant black bean aphid targets most.
- Leave pods on the plant to dry fully. For dried storage, don't pick pods young -- leave them on the plant until they've turned black and papery and the beans inside rattle.
- Shell and finish drying indoors. Shell the dried pods and spread the 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. Notice several zones show an autumn/winter sowing window rather than spring -- overwintering broad bean is a real, established technique in milder zones, giving an earlier and often heavier crop the following summer. Tropical shows no window at all, since this site's own yield data marks broad bean as not viable there.
Calories & Yield
Broad bean is a genuine calorie staple when dried at about 3,410 kcal per kg -- in the same league as wheat and this site's other dried pulses. Mediterranean and Maritime zones give the best yields here.
| Climate Zone | Yield per plant | Calories per plant | Viability |
|---|---|---|---|
| Tropical / Humid | -- | -- | Not viable |
| Subtropical | 0.15 kg | 511.5 kcal | Viable |
| Mediterranean | 0.18 kg | 613.8 kcal | Viable -- best yield |
| Temperate Maritime | 0.18 kg | 613.8 kcal | Viable -- best yield |
| Temperate Continental | 0.17 kg | 579.7 kcal | Viable |
| Cool / Boreal | 0.12 kg | 409.2 kcal | Viable |
| Arid / Semi-Arid | 0.1 kg | 341 kcal | Viable |
| Highland / Alpine | 0.12 kg | 409.2 kcal | Viable |
Figures per plant sown, dried weight, from the site's own crop database.
Varieties Worth Knowing
Broad bean varieties differ mainly in hardiness and seed size. 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
Broad bean crosses with fava/field bean -- the same species (Vicia faba), just a field-scale variety group. It's biennial-shaped: plant, overwinter, flower and set seed the following year.
SERVINGS, NOT DAILY CALORIES This works out plate-sized servings of broad 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 broad 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
Broad bean is grown here specifically for dried storage, not fresh eating -- pods are 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 broad 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 Broad Beans Without Bought Inputs
Black bean aphid is the main pest to watch for -- it clusters thickly on soft growing tips, and heavy infestations can weaken the whole plant.
Pinching out the growing tips once the lowest pods have set is the single most effective input-free defence -- it removes exactly the soft new growth aphids target, and diverts the plant's energy into filling pods instead.
Broad 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
Is broad bean self-pollinating, and does that mean I don't need to isolate it?
It's nominally self-pollinating, but that's misleading here -- broad bean flowers are heavily visited by bees, and documented outcrossing rates run from 5% to as high as 60% depending on variety, environment and whether a natural barrier is present. Unlike most self-pollinating legumes on this site, broad bean genuinely needs real isolation distance if you're saving pure seed.
Does broad bean cross with the other beans on this site?
No -- broad bean (Vicia faba) is a different genus entirely from both common bean (Phaseolus vulgaris, covering Borlotti/Haricot and French bean) and runner bean (Phaseolus coccineus). It does genuinely cross with field bean, though, since field bean is the same species as broad bean, just a field-scale variety.
How cold and hot can broad bean survive?
Roughly -10°C to 27°C, though tolerance varies a lot by variety -- some cultivars only handle light frost, while hardier ones survive down toward -10°C. Heat is the bigger practical limit: sustained temperatures above about 27°C sterilise the flowers, and unlike common bean or runner bean, broad bean simply won't set pods in hot weather at all.
Why isn't broad bean viable in Tropical zones on this site?
Broad bean is a genuine cool-season crop and its flowers become sterile in sustained heat -- the opposite requirement from most calorie-dense legumes, which is exactly the problem in a Tropical zone with no real cool season at all.
Is broad bean a good calorie crop for self-sufficiency?
Very good -- around 3,410 kcal per kg dried, in the same league as wheat and the other dried pulses on this site. It also fixes its own nitrogen, so it's improving the soil it's grown in rather than depleting it, on top of the calories it provides.
Do I need pesticides to grow broad beans?
No. Black bean aphid is the main pest to watch for, clustering thickly on growing tips, and pinching out the tops once the first pods have set removes most of what attracts them without any spray needed.