Vegetable
Fava bean (broad bean)
Vicia faba · Fabaceae
Also called: Broad bean, Faba bean, Horse bean
Fava bean (broad bean) (Vicia faba) is a moderate-water vegetable well suited to Tucson and the low desert. It thrives in full sun.
Fava bean (broad bean) at a glance
- Water use
- Moderate (established)
- Sun
- Full sun (6+ hours).
- Mature size
- 2-4 ft tall, 12-18 in wide; upright bushy plants often need light support.
- Growth rate
- Moderate (about 75-90 days to green-shell harvest).
- Bloom
- White with black blotches (fragrant), Blooms late winter to early spring (Tucson); harvest green pods in spring or leave for dry beans.
- Cold hardiness
- Cool-season legume, frost-hardy to about 20 F; unlike common beans it thrives in cool weather and dislikes heat. USDA 9a-9b.
- Soil
- Well-drained loam with added compost; pH 6.0-7.5, tolerant of alkaline desert soils. As a legume it fixes nitrogen and improves soil.
- Native range
- Mediterranean / Middle East and North Africa (ancient cultigen)
- Best used as
- Edible vegetable (green-shell or dried beans), Nitrogen-fixing cover crop / green manure, Pollinator forage in the cool season
- Wildlife
- Flowers are excellent early-season bee and pollinator forage; black bean aphids are the main pest. Often grown as a winter cover/green-manure crop to fix nitrogen.
- Toxicity
- Edible for humans, but raw or undercooked favas can trigger favism (hemolytic anemia) in people with G6PD deficiency. Generally not a concern for landscape pets.
How to grow Fava bean (broad bean) in Tucson & the low desert
Watering
Cool-season planting: per the Pima County guide, sow seed Sep-Oct (fall) and Feb-early Mar (late winter) for a spring harvest before heat. Water deeply 1-2x/week, keeping soil evenly moist during flowering and pod set; reduce as pods mature.
Fertilizer & nutrients
Light feeder for nitrogen (fixes its own via Rhizobium, inoculate seed if soil is new). Provide phosphorus and potassium; avoid heavy nitrogen, which promotes foliage over pods. A balanced low-N fertilizer or compost at planting is sufficient.
Pruning & care
Pinch out the growing tips once the lowest pods set, this discourages black bean aphids and channels energy into pods. Stake or corral tall plants against wind.
Notes
A cool-season legume well suited to Tucson winters, plant in fall or late winter and harvest before summer heat. Doubles as a soil-building cover crop. Caution favism risk for G6PD-deficient individuals. Not native.
Sources: University of Arizona Cooperative Extension - Pima County Vegetable Planting and Harvesting Guide, shows Fava S Feb-early Mar and S Sep-Oct (extension.arizona.edu)