Mint

Quick facts

Category

herbs soft

Difficulty

beginner

Days to harvest

60 to 90 days

Harvest type

continuous production over weeks or months

Spacing

30 cm between plants

Environment

Temperature

13–25°C

pH

5.5 to 6.5

EC (hydroponic)

1.4 to 2 mS/cm

Daily light

12 to 18 mol/m²/day

Climate and zones

USDA zones

3 to 11 (winter low around -40°C or warmer)

Frost tolerance

very hardy (survives deep cold)

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

Mint works in:

• deep water culture (rafts)
• vertical / aeroponic tower
• media bed (ebb and flow)
• wicking bed
• drip / Dutch buckets
• soil bed

Root mass is heavy - thin-channel systems (NFT, vertical towers) can't hold this crop mechanically, hence the system list above.

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 (mint 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.

Companion-growing notes

• Heavy uptake of nitrogen, potassium. Co-grown crops with the same demand will end up deficient even at "correct" EC. Plan around this in shared reservoirs.
• Releases compounds through the roots that can mildly inhibit other crops in the same reservoir or bed. The effect is usually subtle but worth knowing if neighbors look stunted.
• High transpiration. Reservoir level will need regular top-ups during fruiting or flowering.

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 extremely easy, aggressively growing hydroponic herb. EC 1.0-2.0 mS/cm. pH 5.5-7.0. Temperature: 10–28°C (wide range; most species prefer cool to moderate conditions). Low to moderate light (DLI 10-18 mol/m2/day; mint tolerates shade better than most herbs). Any hydroponic system works. Propagation by stem cuttings (root in water in 5-7 days) or by division of existing clumps. Growth is vigorous to aggressive; in shared hydroponic systems, mint runners can invade neighboring plants' space. Give it a dedicated container or section. Harvest by cutting stems 5 cm above the base; the plant regrows rapidly. Pinch flower buds to maintain leaf production (flowering reduces leaf quality). For tea: steep 8-12 fresh leaves in hot water for 5 minutes. For Moroccan mint tea: steep spearmint with green gunpowder tea and pour with sugar from a height to aerate. Fresh mint for cocktails (mojitos, mint juleps, gin and tonic with mint) should be spearmint; peppermint is too intense. One mint plant produces more herb than most households can use; the excess can be dried, made into mint syrup, or composted.

Further reading

• Best crops for hydroponic beginners
• Getting started with hydroponics: which system to build first
• The Kratky method: grow lettuce with zero electricity