An early start, because favas go in when you’d sow peas, weeks before the tomatoes
For tall types, a couple of stakes and some string to hold the row up once it’s heavy with pods
A spot that didn’t grow beans or peas in the last three years
Fava beans are the bean for gardeners who hate waiting. They’re a legume like any other bean, but they want cool weather. Sown early, they grow through spring and finish before the summer heat that green beans wait for.
Is a fava bean a legume?
All three names are the same plant, Vicia faba. It’s in the legume family (Fabaceae) with peas, beans and clover, and like them it can partner with soil bacteria to take nitrogen from the air. Its botanical name puts it among the vetches, and in the garden it behaves much more like a pea than a green bean: cold-hardy, happiest in cool weather, and quick to give up once the days turn hot.
The beans you cook are the large-seeded kind, grown as a vegetable. A small-seeded form, often called the field bean or horse bean, is grown to feed livestock.
When do I plant fava beans?
Favas are hardy, so the planner schedules them on the early window it gives peas and other cold-tolerant crops, ahead of the frost-safe date the tender crops wait for:
Cold-hardy annuals can be sown or transplanted before the last spring frost (hardy crops about three weeks before, half-hardy about two weeks before). Tender crops wait for the frost itself.
If you skip this, it still grows, just less well. The planner suggests it.
How it works: Cold hardiness. Hardy crops tolerate hard frost and half-hardy crops tolerate light frost, so they can occupy the ground weeks before frost-tender crops are allowed in. The offset is measured from the last spring frost.
Evidence: checked against 2 sources in the research-based literature.
The reason to take that early date seriously is the other end of the season. Favas like cool weather: they do best when days sit in the 15–20°C60s°F, and yields drop once daytime temperatures climb past about 25°C75°F. A late sowing runs straight into summer and gives you a handful of pods before the plants quit. Where summers come on hot and fast, plant them for the mildest stretch of your year; the earliest possible spring sowing is often the difference between a crop and a disappointment.
Sow them straight into the bed, about 15 cm6 in apart along the row.
Do fava beans need support?
Favas grow as stiff, upright bushes, so there’s no trellis to build. How tall they get depends on the type:
Tall favas (Aquadulce, Windsor, Masterpiece) reach 1–1.5 m3–5 ft. They stand on their own while they’re growing, but once they’re loaded with pods they can lean or flop over. A stake at each end of the row with a line of string down each side keeps them standing.
Dwarf favas (The Sutton, Robin Hood) stay around 30–45 cm12–18 in and hold themselves up. They’re the better pick for a small bed or a windy spot.
Tell the planner which type you’re growing and it only asks for support when the type needs it. The staking guide covers the stakes and string.
When do I pick fava beans, and can I eat them raw?
The pods grow pointing up and then start to droop as the beans inside fill out. For fresh beans, pick them while the pods are still green and you can see the seeds starting to bulge. Shell the beans out of the pod, then slip off each bean’s pale outer skin, before or after cooking. Beans left on the plant until they’re fully mature can be dried and used like any dry bean.
Watch for aphids, which favas are prone to. Beneficial insects and pests both feed at the flowers.
One caution matters more than any growing tip. Some people are sensitive to raw fava beans and can become quite ill after eating them. The condition is called favism, a severe anemia in which red blood cells are destroyed. It happens in people with an inherited predisposition, after eating raw beans or breathing the pollen. It’s most common in people of Mediterranean ancestry, but there’s no way to predict who is sensitive. Always cook favas fully before eating them.
Do fava beans add nitrogen to the soil?
Like other legumes, favas can take nitrogen from the air, but only with the right partner bacteria in the soil. Ground that hasn’t grown their kind lately may be short of it:
Beans, peas and other legumes only fix nitrogen with the right soil bacteria. Ground that hasn't grown their kind recently may have too few, so they fix less.
If you skip this, it still grows, just less well. The planner suggests it.
How it works: Nitrogen fixation happens in root nodules formed by Rhizobium or Bradyrhizobium bacteria specific to each legume group. On ground that has not grown that legume group before (a new bed, a soil-less mix, a long gap in the rotation, a fumigated or strongly acid soil), the matching strain can be absent or sparse, so nodulation and fixation are reduced until a population builds.
Evidence: checked against 1 source in the research-based literature.
Rhizobia bacteria are fairly specific as to which legumes they will infect, form nodules on the roots of, and for which they will fix nitrogen
Remedy
On first-time legume ground, coat the seed at sowing with the inoculant matched to the crop's group (garden peas and beans, soybean, and clover each take a different one). Ground that has grown that legume recently usually needs none. It is a cheap one-time step, advised where the history is absent and never required.
Favas are also often grown as a cover crop, especially through winter. The cover crops guide covers that use.
What favas don’t want is to follow themselves, or any other legume. The root diseases that build up under beans and peas build up under favas too, so give the ground a break:
Do not plant legumes in ground that held legumes within 3 years; the root rots build where they repeat, and the worst of them outlast any garden rotation.
If you skip this, you lose real yield. The planner warns you.
How it works: Bean and pea root rots (Fusarium solani, Rhizoctonia, Pythium, Aphanomyces) and white mold (Sclerotinia sclerotiorum) survive in soil as spores and sclerotia and build where legumes follow legumes; a three-year break holds the common ones down. Fusarium needs longer, and Aphanomyces oospores and white mold's sclerotia persist for many years, so rotation reduces but cannot clear them.
Evidence: checked against 4 sources in the research-based literature.
Fields with a long history of pulses in close rotations (every 2-3 years) are at greatest risk
Remedy
Plant legumes in different ground, or wait until 3 years have passed since this ground last held them. Where root rot has shown, make it longer, and keep the ground draining freely, because every one of these rots is worse in wet soil.
