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Plant care

Mint care

Mentha

Also called peppermint, spearmint, garden mint.

RHS H7USDA 3-11Toxic to petsIndoor 30-60 cm tall

Watering rhythm

Medium indirect light (a couple of metres from a window)

Keep evenly moist

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Light

Medium indirect light (a couple of metres from a window)

Soil

Rich, moisture-retentive loam

Humidity

40-70% (outdoor)

Temp

13-24°C

Pet safety

Toxic to pets

Mature size

30-60 cm tall

Care at a glance

Light

The Goldilocks zone. Not the south-facing windowsill (too hot, too direct), not the back of the room (too dim, growth stalls). Full sun to part shade. Afternoon shade keeps the leaves tender. If you can't decide, a free phone lux-meter app aimed at the leaf at noon should read between 800 and 1,500 lux.

Watering

Watering mint: keep evenly moist. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Mint likes damp soil and never sulks at a deep watering. In a pot, water as soon as the surface dries.

Soil and pot

Mint grows best in rich, moisture-retentive loam. Tolerates a wide range. Container culture prevents the rhizomes from invading the rest of the garden. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Mint sits happiest at around 40-70% (outdoor) humidity and 13-24°C (55-75°F). Tolerant of a wide range. If you keep the room above 13 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed mint sparingly. A balanced feed every 6 weeks during the growing season is plenty. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on mint in the Growli community. Where a problem matches one of our diagnostic guides, click through for the full step-by-step recovery plan written for mint specifically.

  • Spreading everywhere — Rhizomes — grow in a sunken pot or dedicated bed.
  • Orange rust pustules under leaves — Mint rust; cut to the ground and dispose of infected stems.
  • Tough woody growth — Plant is exhausted; divide and replant every 2-3 years.
  • Pale weak leaves — Too much shade or poor soil.

Companion plants

Mint pairs well with Cabbage, Carrot, and Tomato (in pots — keep mint contained). These are species with similar light and water needs, so you can grow them in the same bed or container without conflict.

Propagation

Almost too easy — stem cuttings root in water in a week, rhizome divisions take instantly. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Mint is toxic to pets. ASPCA lists garden mints as toxic to cats and dogs due to essential oils. A nibble is harmless; large amounts cause vomiting and diarrhoea. Pennyroyal (Mentha pulegium) is significantly more toxic and should be avoided in pet homes. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Mint care — frequently asked questions

What is Mint?

Mint (Mentha) is a culinary herb with a spreading rhizomatous perennial herb growth habit, reaching 30-60 cm tall, spreading at maturity. Mint is a vigorous spreading perennial herb that thrives in damp soil and partial shade. Best grown in a sunken pot or dedicated bed to stop it taking over.

How much light does mint need?

Mint grows best in medium indirect light (a couple of metres from a window). Full sun to part shade. Afternoon shade keeps the leaves tender.

How often should I water mint?

Water mint keep evenly moist. Mint likes damp soil and never sulks at a deep watering. In a pot, water as soon as the surface dries. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is mint toxic to cats and dogs?

Mint is toxic to pets. ASPCA lists garden mints as toxic to cats and dogs due to essential oils. A nibble is harmless; large amounts cause vomiting and diarrhoea. Pennyroyal (Mentha pulegium) is significantly more toxic and should be avoided in pet homes.

What USDA hardiness zone does mint grow in?

Mint is rated for USDA zone 3-11 (varies by species) and RHS hardiness H7. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Mint deep-dive guides

Every aspect of mint care, each with its own calibrated guide:

Related guides

Mint is also known as peppermint, spearmint, and garden mint.