Orach / Orache (Atriplex hortensis) growing guide

Quick facts

Category: leafy greens
Difficulty: beginner
Days to harvest: 40 to 60 days
Harvest type: cut leaves, plant regrows for repeated harvests
Spacing: 25 cm between plants

Environment

Temperature: 10–26°C
pH: 6 to 8
EC (hydroponic): 1.2 to 2 mS/cm
Daily light: 14 to 20 mol/m²/day

Climate and zones

USDA zones: 4 to 9 (winter low around -34°C or warmer)
Frost tolerance: tolerates light 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

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

Orach works in:

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 (orach works in the media listed below).

Medium	pH effect	Water retention	Bacterial surface
Expanded clay pebbles (LECA)	neutral / inert	low	high
Coco coir (Coconut coir)	slightly acidic	high	moderate
Soil-based mix (Potting soil)	varies by source	high	high

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.

Stage	N	P	K	EC target (mS/cm)
seedling	1	1	1	0.7
vegetative	3	1	2	1.5

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

An easy, fast, visually striking hydroponic leafy green. EC 1.2-2.0 mS/cm. pH 6.0-8.0 (salt-tolerant; handles alkaline conditions better than most greens). Temperature: 15–30°C (wider heat tolerance than true spinach). Moderate light (DLI 12-20 mol/m2/day). Any hydroponic system works. From seed to baby leaf: 3-4 weeks. Full-sized: 6-8 weeks. Harvest young leaves for salad (the red and purple varieties add dramatic color to salad mixes). Older leaves are better cooked (sauteed like spinach; the color of red orach bleeds into cooking liquid, similar to beets). The plant grows tall; if space is limited, pinch the growing tip at 30 cm to promote bushy, lateral growth. Succession plant every 3 weeks. Self-seeds aggressively in outdoor settings. For commercial hydroponic salad mix producers, red and purple orach is one of the most visually impactful additions: the deep magenta color is genuine (not dyed), eye-catching, and rare among leafy greens. Premium pricing reflects the novelty and visual appeal.

Notable varieties

A starting shortlist of cultivars worth knowing about. Not exhaustive: the seed catalogs list hundreds of named varieties. These are the ones home growers commonly choose between.

Cultivar	Type	Days	Notes
Magenta Magic	open-pollinated	45	Deep magenta-purple leaves and stems, the most ornamental of the orachs. Holds color through the season instead of fading green in heat. Common in cut-flower and edible-landscape mixes as much as kitchen gardens.
Aurora	open-pollinated	45	Mixed-color seed strain producing green, gold, pink, and red plants from one packet. Useful for visual variety in a salad bed; flavor is identical across colors.
Golden	open-pollinated	45	Pure chartreuse-yellow leaves on green stems. Bolts slightly faster than the red types but the color is striking. Loses some intensity in deep shade.
Triple Purple	open-pollinated	50	Selection bred for the deepest, most uniform purple of the cultivated orachs. Less variation from plant to plant than Magenta Magic. Stalks are striking in late-summer floral arrangements.