Lavender (English)

Quick facts

Category

herbs woody

Difficulty

intermediate

Days to harvest

365 to 545 days

Harvest type

continuous production over weeks or months

Spacing

50 cm between plants

Environment

Temperature

5–28°C

pH

6.5 to 7.8

EC (hydroponic)

0.8 to 1.4 mS/cm

Daily light

25 to 40 mol/m²/day (strict, will fail outside this range)

Climate and zones

USDA zones

5 to 9 (winter low around -29°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

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

Lavender (English) works in:

• soil bed
• drip / Dutch buckets

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 (lavender (english) 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

Not recommended for pure aquaponics. Fish waste alone doesn't provide enough of the nutrients this crop demands (typically potassium, calcium, or boron). It can be grown in a hybrid system where the reservoir is supplemented with hydroponic-style nutrients, but expect to dose actively.

Care notes

A drought-tolerant Mediterranean herb that needs well-drained conditions, making it somewhat contrary to typical hydroponic culture. Container growing (15 L) with very well-drained media (perlite, pumice, or expanded clay; avoid water-retentive mixes). EC 1.0-1.5 mS/cm (light feeder; rich conditions produce lush but weakly aromatic growth). pH 6.5-7.5 (tolerates slightly alkaline). Temperature: 10–30°C (Mediterranean climate; cold-hardy to zone 5 once established). Full sun (DLI 18-28 mol/m2/day). The plant is a long-lived perennial (10-20 years) that produces harvestable flower stems starting in the second year. Harvest flower stems when the bottom third of the flower spike has opened; this is peak essential oil content. Dry flowers by hanging bundles upside down in a warm, dry, dark room for 1-2 weeks. Strip dried flowers from stems for culinary use. Prune annually in spring (cut back to just above the woody base) to prevent the plant from becoming leggy. Lavender does not tolerate wet feet; overwatering is the primary cause of failure. For aquaponics growers, lavender works best in a separate container with its own drainage, irrigated sparingly with system water.

Further reading

• Best crops for hydroponic beginners
• The Kratky method: grow lettuce with zero electricity