Garlic (Allium sativum)

Environment

The bounded range this crop tolerates.

Temperature

5152535

4–25°C

pH

45.578.5

6–7

EC (hydro)

01234

1.4–1.8 mS/cm

Daily light

5152535

15–25 mol/m²/d

✓Single harvest

Climate and zones

USDA zones: 3–9 (winter low around -40°C)
Frost: very hardy (survives deep cold)
Season: cool (spring/fall)

✓Outdoor year-round (in zone)

✓Outdoor in growing season

✓Unheated greenhouse / hoop

·Heated greenhouse

✓Indoor (heated home)

·Indoor hydroponics + grow lights

Growing systems

Root mass: moderate.

·Deep water culture (rafts)

·NFT channels

·Vertical / aeroponic tower

·Drip / Dutch buckets

✓Media bed (ebb and flow)

✓Wicking bed

✓Soil bed

Growing media

Medium	pH effect	Retention	Bacterial surface
Soil-based mix (Potting soil)	varies	high	high
Coco coir (Coconut coir)	slightly acidic	high	moderate

Nutrient demand by stage

NPK ratios are relative weights. EC targets shift through the plant's life.

Stage	N	P	K	EC (mS/cm)
seedling	2	1	1	1.2
vegetative	2	2	3	1.6

Companion-growing notes

Heavy uptake of phosphorus. Co-grown crops with the same demand will end up deficient even at "correct" EC.
Releases root compounds that can inhibit other crops in a shared reservoir.

Aquaponics suitability

Compatible

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 challenging hydroponic crop because bulb formation requires specific day-length and temperature triggers that are difficult to replicate in controlled environments. Garlic cloves are planted in fall, grow through winter, and form bulbs as days lengthen in spring/summer. This natural cycle takes 7-9 months. In hydroponic media beds: plant individual cloves (pointed end up, 5–8 cm deep) in autumn. EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: cold tolerance through winter (garlic needs 4-8 weeks below 5°C for vernalization, which triggers bulb formation in spring). Full sun during the growing season (DLI 16-22 mol/m2/day). Hardneck varieties are better for cold-climate growers. Harvest in summer when the bottom 3-4 leaves have browned but the top 4-5 are still green. Cure bulbs in a warm, dry, well-ventilated space for 2-4 weeks before trimming and storing. Garlic scapes (the curly flower stalks of hardneck varieties) are a bonus harvest in late spring, with a mild garlic flavor excellent in pesto. For aquaponics growers, garlic in outdoor media beds follows the natural seasonal cycle and integrates well with other root and allium crops.

Notable varieties

Cultivar	Type	Days	Notes
Music	open pollinated	270	Hardneck Porcelain type. Large cloves (4-6 per bulb), strong flavor, the most popular hardneck for cold-climate gardeners. Zones 3-7.
German Extra Hardy	heirloom	270	Porcelain hardneck, very cold-tolerant, stores 6-8 months. Adapted to USDA zones 3-6 specifically.
Inchelium Red	heirloom	240	Artichoke softneck from Washington's Colville Reservation. 12-20 cloves per bulb, mild flavor, stores 6-9 months. The softneck winner of the 1990 Rodale garlic taste test.
California Early	open pollinated	240	Artichoke softneck. The commercial supermarket variety; mild, large bulbs, doesn't require as much cold exposure. Suits zones 7-10.
Spanish Roja	heirloom	270	Rocambole hardneck. Considered the gold standard for flavor among garlic enthusiasts; peels easily, intense aroma. Doesn't store as well as Porcelains (4-6 months).