Fava beans

Quick facts

Category

fruiting

Difficulty

beginner

Days to harvest

75 to 100 days

Harvest type

continuous production over weeks or months

Spacing

20 cm between plants

Environment

Temperature

4–22°C

pH

6 to 7.5

EC (hydroponic)

1.4 to 2 mS/cm

Daily light

15 to 25 mol/m²/day

Climate and zones

USDA zones

2 to 9 (winter low around -46°C or warmer)

Frost tolerance

very hardy (survives deep cold)

Season

cool (spring and fall crops)

Viable growing environments:

• outdoor year-round (in zone)
• outdoor in growing season (annual)
• unheated greenhouse / hoop house

USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.

Growing systems

Fava beans works in:

• media bed (ebb and flow)
• soil bed

Growing media

The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (fava beans works in the media listed below).

Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.

Nutrient demand by stage

NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.

Aquaponics suitability

Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.

Care notes

One of the few legumes that thrives in cool weather, making it ideal for fall, winter, and early spring hydroponic production when warm-season crops are dormant. EC 1.5-2.5 mS/cm. pH 6.0-7.5. Temperature: 10–22°C (grows actively in cold that would stall most other crops; tolerates light frost). Moderate light (DLI 14-20 mol/m2/day). Media beds or large containers (the plants grow 60–120 cm tall and need staking). Nitrogen fixation via Rhizobium leguminosarum may be absent in sterile hydroponic media; inoculate seeds or provide nitrogen through the nutrient solution. From seed to fresh bean harvest: 80-100 days. From seed to dry bean harvest: 120-150 days. Harvest fresh favas when pods are plump and bright green. For dried storage, leave pods on the plant until fully brown and dry, then shell and store. Chocolate spot (Botrytis fabae) is the main disease in humid conditions; good airflow and avoiding overhead wetting helps. Black bean aphids colonize stems and tips aggressively; monitor and treat early.

Further reading

• Getting started with hydroponics: which system to build first
• Understanding nutrient solutions: N-P-K, micronutrients, and why your lettuce turned yellow