Growing the Herb Mint

Mints should be planted where they will not encroach on other plants, as they spread so readily that, unless curbed, they are likely to become a pestiferous weed. It is ideal for container and hydroponic culture.

Mint revels in deep, rich, moist ground and requires little care except manicuring or fertilizing in the spring. However, as the stems grow rapidly and the leaves become thin and small as the season advances, it is advisable to cut down from a third to a half of the patch when 6 or 8 inches high, drying the leaves and putting them in tight jars for winter use. Then soak the cut over area with liquid manure to stimulate a second crop of foliage. A month later, treat another area similarly. Thus a succession of succulent foliage may be had all season.

Orange spots on the backs of mint leaves are caused by a rust which can be controlled by using an organic garden dust.

Growing Cultures

Outdoors, in containers, and hydroponics.

Plant Height

Peppermint and spearmint usually grow to a height of 12 to 18 inches (30-45cm).

Plant Spacing

Peppermint plants should be spaced between 18 and 24 inches (45 and 60 cm) apart. Spearmint plants should be placed between 3 and 4 feet (90-120cm) apart.

Preferred pH Range

Mints will grow in a relatively wide pH range between 5.6 (mildly acidic) and 7.5 (mildly alkaline) with a preferred range between 6.5 and 7.0.
Propagation

Start seed indoors 8 to 10 weeks prior to last spring frost. Or, sow directly outdoors in partially shaded, moist soil. Propagates best through softwood cuttings. Also propagates well through rootball division.

Seed Germination Period

Mint seeds generally germinate between 12 and 16 days.

Number of Seeds per Gram

There are between approximately 17,000 and 20,000 mint seeds per gram, depending on variety.

Soil Requirements

Mints prefer a rich, moist, and well-drained soil.

Alternative Growing Media

Soilless potting mixes (Pro-Mix, Sunshine Mix, etc.), perlite, vermiculite, rockwool, coco peat, Oasis Rootcubes.

Time From Seed to Saleable Plant

Most cultivars grown from cuttings. Seed material not recommended for pot sales. Plugs to saleable plant, 4 weeks.

Sun & Lighting Requirements

Mints grown outdoors prefers full sun.

Both peppermint and spearmint will grow indoors satisfactorily under standard fluorescent lamps, and exceptionally well under high output T5 fluorescent grow lights, compact fluorescent, or high intensity discharge (metal halide or high pressure sodium) plant growing lights. Keep standard fluorescent lamps between 2 and 4 inches from the tops of the plants, high output and compact fluorescents approximately one foot above the plants, and HID lights between 2 and 4 feet above the plants, depending on wattage.

Have an oscillating fan gently stir seedlings for at least 2 hours per day to stimulate shorter, sturdier, and more natural plant habit.

USDA Hardiness

Perennial. Peppermint zones 3a to 7b; spearmint 4a to 11.

Water Requirements

Water regularly, being careful not to overwater. Allow soil to go almost dry between watering, then soak thoroughly.

Potential Plant Pests and Diseases

Mints can be susceptible to mealybug, whitefly, aphids, and spider mites and can be particularly susceptible to rust.

Companion Planting

Peppermint and spearmint are beneficial to cabbage, kohlrabi, broccoli, and the other kales by repelling or distracting cabbage fly, ants, and cabbage looper. Spearmint is noted for its ability to repel or distract ants and aphids.

Special Notes

Seeds are poisonous if ingested. Mint may become a noxious weed and invasive. Mints are known to attract bees, butterflies and birds. Aromatic foliage. Suitable for containers.