French tarragon

Quick facts

Category

herbs woody

Difficulty

intermediate

Days to harvest

90 to 120 days

Harvest type

continuous production over weeks or months

Spacing

50 cm between plants

Environment

Temperature

10–26°C

pH

6.5 to 7.5

EC (hydroponic)

1 to 1.6 mS/cm

Daily light

12 to 20 mol/m²/day

Climate and zones

USDA zones

4 to 9 (winter low around -34°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

French tarragon works in:

• media bed (ebb and flow)
• wicking bed
• 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 (french tarragon 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

A moderately demanding perennial herb. EC 1.0-1.8 mS/cm. pH 6.0-7.5. Temperature: 15–25°C (cool to moderate; struggles in sustained heat above 30°C and high humidity). Full sun (DLI 16-22 mol/m2/day). Well-drained media is critical; tarragon roots rot in waterlogged conditions. Container (15 L) with perlite or expanded clay. Propagation ONLY by division of existing clumps or stem cuttings; if someone offers you tarragon seeds, it's the flavorless Russian type. Purchase a confirmed French tarragon plant from a reputable herb nursery. Harvest by cutting stem tips; the plant branches when pinched. The flavor is best in fresh leaves; dried tarragon is acceptable but loses much of the anise complexity. For tarragon vinegar: pack fresh tarragon sprigs into a bottle, cover with white wine vinegar, steep for 2-4 weeks. The resulting vinegar is indispensable for vinaigrettes and bearnaise. French tarragon goes dormant in winter; the above-ground growth dies back and new shoots emerge in spring.

Further reading

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