Garden cress

Quick facts

Category

leafy greens

Difficulty

beginner

Days to harvest

10 to 25 days

Harvest type

single harvest then replant

Spacing

5 cm between plants

Environment

Temperature

7–22°C

pH

6 to 7.5

EC (hydroponic)

1 to 1.6 mS/cm

Daily light

10 to 16 mol/m²/day

Climate and zones

USDA zones

3 to 11 (winter low around -40°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

Garden cress 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 (garden cress 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

The fastest harvestable hydroponic crop. EC 0.5-1.5 mS/cm (very light feeder, especially for microgreens). pH 6.0-7.0. Temperature: 10–22°C (cool-season; bolts rapidly above 24°C). Low to moderate light (DLI 8-16 mol/m2/day; for microgreens, even windowsill light is adequate). For microgreens: scatter seed densely on a moist growing pad (hemp, coir, or paper towel), mist daily, harvest at 7-10 days when cotyledons are fully expanded. For baby salad leaves: space seeds in NFT, DWC, or small containers, harvest at 14-21 days. The peppery flavor is most intense in mature leaves and milder in microgreens. Garden cress can be succession-planted every 5-7 days for continuous microgreen production year-round. Each tray of microgreens produces harvestable greens in about a week, making it one of the most rapid-turnover crops available. For commercial microgreen growers, cress is a staple variety. For home growers, it's the fastest path from seed to plate in any growing system.

Further reading

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