How to Grow Tarragon Hydroponically

Quick answer

French Tarragon (Artemisia dracunculus var. sativa) reaches first harvest in 60–80 days from a rooted cutting, at pH 6.0, EC 1.4, DLI 18, and air 18–26 °C. It's a perennial herb with distinctive anise-licorice flavor essential to French cuisine. True French tarragon cannot be grown from seed — propagate from cuttings or divisions only. Best in drip or ebb-and-flow.

Conditions

Parameter	Value
pH	5.5–6.5 (6.0 ideal)
EC	1.0–1.6 mS/cm
Air temp	18–26 °C
Water temp	18–22 °C
Humidity	40–60%
DLI	16–20 mol/m²/day
Photoperiod	14–16 h
Spacing	22 cm
Days to harvest	60–80 (rooted cutting)
Yield/plant	~100 g/year, perennial 3–4 years

The French vs Russian tarragon distinction

Critical to understand before you start:

• French tarragon (A. dracunculus var. sativa) — true culinary tarragon with strong anise-licorice flavor. Cannot be grown from seed. Only propagated from cuttings or root divisions. Any "tarragon seed" sold is Russian tarragon.
• Russian tarragon (A. dracunculoides) — closely related but virtually flavorless. Grows from seed easily but produces nothing worth eating.
• Mexican tarragon (Tagetes lucida) — different genus, anise-flavored marigold relative. Sometimes substituted in warm climates. Not true tarragon but useful.

If you bought seed and grew tarragon successfully, you most likely have Russian tarragon — which is not what you want for cooking.

Getting actual French tarragon

The only ways:

• Buy a live plant from a herb specialist nursery or garden center.
• Take a cutting from a friend's established French tarragon.
• Order rooted divisions from mail-order herb suppliers (Mountain Valley Growers, Richters, etc.).

Garden centers often mislabel — verify by tasting a leaf. French tarragon has unmistakable strong anise-licorice flavor.

Recommended system

Drip with coco coir + perlite — best fit. The drainage matches tarragon's preference for slightly dry roots.

Ebb and flow with clay pebbles — also excellent.

DWC — works but produces slightly milder tarragon. Acceptable if drip isn't available.

NFT — not ideal; uniform moisture doesn't suit tarragon.

Kratky — not recommended for perennial tarragon.

Propagation from cuttings

The standard process:

1. Cut 8–10 cm stem tips from any healthy French tarragon plant.
2. Strip lower 2/3 of leaves.
3. Dip cut end in rooting hormone (recommended).
4. Place in moist perlite or coco coir.
5. Cover loosely with plastic; maintain 22 °C with bottom heat.
6. Roots form in 21–35 days.
7. Transfer rooted cutting to 3-inch net cup in drip system.

First useful harvest at week 10–12 from rooted cutting.

For long-term propagation, save root divisions from established plants — each year, split a mature plant in half and replant one division.

Light and temperature

Tarragon prefers warm-but-not-hot conditions:

• Air temperature 18–26 °C. Tolerates slightly cooler than rosemary or oregano.
• DLI 16–20. Less light-hungry than Mediterranean herbs.
• Photoperiod 14–16 hours.
• Humidity 40–60%.

Tarragon dies back naturally in cold conditions (under 10 °C) — outdoors this is winter dormancy. Indoors, maintain steady warmth for continuous production.

Nutrients

Standard 3-part hydroponic nutrient at EC 1.4 mS/cm. Tarragon specifically:

• Moderate nitrogen. Excess produces lush but flavorless growth.
• Adequate iron for the bright green leaf color.
• Cal-mag at 1 mL/gallon.

Lower EC (1.0–1.2) often produces more concentrated flavor at the cost of yield.

Common problems

• Bland flavor — wrong variety (Russian instead of French), or excess water/N.
• Yellowing leaves — usually root issues from overwatering. Reduce water.
• Leggy growth — insufficient light. DLI to 18.
• Stem rot at base — water touching stem. Lift net cup.
• No new growth — temperature too low or plant stressed.
• Powdery mildew — humid stagnant air.

Pruning and longevity

Tarragon develops a woody base after a year. To maintain productivity:

• Pinch soft growth tips every 4–6 weeks for bushier plant.
• Cut back hard once a year (50–60% reduction) in late winter or early spring.
• Divide every 2–3 years when the plant clump becomes too large for the bucket.
• Replace plants every 4 years — French tarragon's flavor weakens with age. Take a cutting from your existing plant to start a fresh one.

Harvest

Cut soft growth at stem tips. Take 20–30% per cut. Tarragon regrows in 21–28 days.

Fresh tarragon keeps 7–10 days refrigerated. Drying is acceptable but loses 30–40% of flavor — fresh is much preferred for cooking. For longer storage, infuse white wine vinegar with fresh tarragon (the classic "tarragon vinegar"), which keeps the flavor for months.

A successful French tarragon plant produces 80–120 g of fresh tarragon per year for 3–4 years.

Why French tarragon is worth the trouble

There is no substitute for fresh French tarragon in:

• Béarnaise sauce — the defining herb.
• Sauce verte and other French herb mixes.
• Chicken tarragon dishes.
• Tarragon vinegar — restaurant-grade culinary infusion.
• Egg dishes — omelets, deviled eggs, custards.

For most home cooks, having fresh French tarragon on demand is unusual enough that growing it pays for itself in dishes you can now make properly.

See also

• Basil
• Lemon balm — anise-flavored cousin
• Chives — French herb companion
• Drip system