Arugula

Quick facts

Category

leafy greens

Difficulty

beginner

Days to harvest

25 to 40 days

Harvest type

cut leaves, plant regrows for repeated harvests

Spacing

15 cm between plants

Environment

Temperature

10–22°C

pH

6 to 7

EC (hydroponic)

0.8 to 1.4 mS/cm

Daily light

10 to 14 mol/m²/day

Climate and zones

USDA zones

3 to 11 (winter low around -40°C or warmer)

Frost tolerance

frost hardy (handles regular frost)

Season

cool (spring and fall crops)

Viable growing environments:

• outdoor year-round (in zone)
• outdoor in growing season (annual)
• unheated greenhouse / hoop house
• heated greenhouse
• indoor (heated home)
• indoor hydroponics under grow lights

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

Arugula works in:

• deep water culture (rafts)
• NFT channels
• vertical / aeroponic tower
• media bed (ebb and flow)
• wicking bed
• 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 (arugula 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 fastest and easiest hydroponic leafy greens. EC 1.0-1.8 mS/cm. pH 6.0-7.0. Temperature: 10–22°C (cool-season crop; bolts rapidly above 24°C). Moderate light (DLI 12-18 mol/m2/day; excessive light accelerates bolting). Harvestable in 3-4 weeks from seed as baby leaves, 5-6 weeks for full-sized leaves. Works perfectly in NFT, DWC, vertical towers, and raft systems. Succession plant every 2 weeks for continuous harvest. The fast growth cycle makes arugula one of the most productive salad crops by weight per square meter per year: 8-12 harvests annually in a temperature-controlled hydroponic system. Cut-and-come-again harvesting extends each planting's productive life. Flavor is best on younger leaves; mature leaves become increasingly bitter and peppery. Flea beetles can be a pest in open greenhouses; fine mesh exclusion netting prevents damage. Wild arugula (Diplotaxis) grows slower but is more heat-tolerant and produces for a longer period before bolting. For commercial hydroponic growers, arugula commands premium prices ($8-15/kg retail in salad mix) and turns over fast. A top-tier hydroponic crop. Arugula is also one of the fastest crops from seed to plate in aquaponics. The shallow root system and low nutrient demand mean it works well even in systems with moderate fish loading. Microgreen arugula (harvested at cotyledon stage, 7-10 days from seed) is another high-value option for hydroponic growers.

Further reading

• The Kratky method: grow lettuce with zero electricity
• What to grow in an aquaponics system (and what won't work)