Grow mint from seed

Mint: Growing and Planting Instructions

Perfect for beginning gardeners, mint is the easiest of all herbs to grow, a perennial hardy in zones 4-9. In addition to flavoring food and drinks, it serves as a natural pest deterrent in the vegetable, herb, or flower garden, and chewing the leaves not only freshens the breath but is said to calm an upset stomach.

Choosing a Mint Variety

Native to the Mediterranean, the genus Mentha has parented more than 3,500 varieties. By far the most commonly grown in this country are Spearmint (M. spicata) and Peppermint (M. x piperita). Both are super easy to grow, taking off like crazy to perfume home or garden all season!

When to Start Mint Seeds

For spring planting, mint seeds can be started indoors in late winter or direct-sown in the warm spring soil. But as a hardy perennial, they can be started anytime until about 2 months before the first frost of fall, or year-round for indoor use.

How to Start Mint Seeds

To sow the seeds indoors, place them on top of the Bio Sponge in your Bio Dome, or on top of the medium in your seed flat. Do not cover the seeds; they need light to germinate. They should sprout within 10 to 15 days at room temperature or slightly warmer (68 to 75°F). Transplant into the garden or container when they have at least 2 sets of true leaves.

To sow the seeds outdoors, place them on top of well-worked soil, then sprinkle a fine layer of vermiculite on top of them. If you are sowing directly into the garden, consider placing a row cover over the seeds until they sprout.

Special Considerations

  • Harvest sprigs from the plant as you need them all season long.
  • Try to pick mint in the morning, when the flavorful oils are strongest.
  • Plant your mint where passersby will brush the foliage, which releases its heady aroma.
  • For new plants from your old ones, root a stem cutting in a glass of water, or divide the entire plant into sections and replant each division.

Growing Tips for Mint Plants

  • Mint thrives best in partial shade and rich, moist soil. However, it is famously unfussy, so chances are it will not only survive but flourish in any light from full sun to deep shade, and any quality of soil provided the drainage is decent. Many gardeners deliberately plant it in less favorable conditions to slow down its spread!
  • Space plants 12 to 18 inches apart in the garden.
  • Throughout the growth months, pinch off the tips of the stems. This makes your plant bushier and less leggy.
  • Avoid using fertilizer on mint.

Pests and Problems to Watch For

Mint’s greatest advantage — its utter ease of growth — is also one of its biggest problems. Do not plant it in an area where other plants must compete for space. If you want it in the garden but without the rapid spread, set it into a container instead, and use a saucer at the base to prevent the roots from growing into the soil below.

View All Know Before You Grow Topics

The mint family is vast and cross pollination is difficult to control, so many sources suggest that mint will not come true from seed. Our mint seeds are grown in isolation and bred with care in a greenhouse setting. Follow this handy How to Grow Mint for seeds guide and grow some flavour.

Mentha sp.
Family: Lamiaceae


Season & Zone
Season: Cool season
Exposure: Full sun to partial shade
Zone: Hardy to Zone 5

Sow indoors 8-10 weeks before last frost, or direct sow in April/May. Seeds should sprout in 10-16 days. Bottom heat will speed germination.

Sow seeds no more than 5mm (¼”) deep in moist soil. Space plants 45-60cm (18-24″) apart.

Mint spreads in the garden with gusto via a vigorous root system, so it may be preferable to confine it to planters on the balcony. Prune plants back hard in early summer to promote good top growth. Bring some inside to grow in a small container over winter if you have a brightly lit windowsill.

Clip leaves or branches as needed throughout the year. Mint is so hardy and tough that it will grow right back. Dry the leaves and flowers for peppermint tea, or use them fresh. The flowers are edible and make salads and sweets come to life.

Companion Planting
Mint attracts earthworms, hoverflies and predatory wasps, and repels cabbage moths, aphids, and flea beetles. Mint is invasive, so it may be better to use cut mint as a mulch around Brassicas, or to restrain it in containers around the vegetable garden. Avoid planting near parsley.

More on Companion Planting.

Quick Guide to Growing Mint

  • Plant mint in spring after the last frost. This fast-growing herb can grow just about anywhere and makes an excellent addition to indoor and outdoor gardens.
  • Space mint plants 18 to 24 inches apart. It’s best to grow them in pots to keep them from taking over your garden (even if you’re planting in the ground).
  • Give your garden a great foundation by improving native soil with several inches of aged compost or other rich organic matter. For container growing, consider a premium bagged potting mix.
  • Keep soil consistently moist and water when the top inch becomes dry.
  • Promote excellent leaf production by regularly feeding with a water-soluble plant food.
  • Once plants are established, harvest mint leaves regularly by pinching off the stems.

Soil, Planting, and Care for Growing Mint

First, start off strong by planting young Bonnie Plants® mint plants. After all, you can’t go wrong with a company that’s been supplying plants to home gardeners for over 100 years! Plant mint in the spring, or in the fall in frost-free climates, setting seedlings 18 to 24 inches apart. Try growing mint in a pot where you can keep it in check and handy near the kitchen for a constant supply of sprigs. To give roots a just-right growing environment, fill the pot with Miracle-Gro® Performance Organics™ All Purpose Container Mix, which contains aged compost to improve soil texture and nutrition. To keep mint from taking over space needed by other plants, you may want to plant it solo in a 10″ pot, then plant the pot in a larger container or even in the ground. Give the pot a turn every week or two to keep roots from escaping through the drainage holes.

If you simply must plant mint directly in the ground (if you’re using it as a ground cover, for example), select a damp area in your garden or yard in either full sun or part shade. Mint prefers fertile soil with a pH from 6.0 to 7.0. If you don’t choose to test your soil, you can simply improve it by adding a few inches of Miracle-Gro® Performance Organics™ All Purpose In-Ground Soil, also enriched with aged compost, in with the top layer of existing soil.

Mint is plenty vigorous on its own, but will grow even better when you pair great soil with regular doses of plant food, especially if you harvest a lot. Feed with Miracle-Gro® Performance Organics™ All Purpose Plant Nutrition (follow label directions), which feeds the soil as well as the plants. Be sure to keep the soil moist via regular watering and add mulch around the plant to help slow the evaporation of all that crucial moisture.

To help keep plants in check, harvest the tips regularly and pull up wayward runners. Mint’s small flowers bloom from June to September; trim these before the buds open to keep the plant compact. Although slightly frost tolerant, the top of mint will eventually die back in winter except in zones 8 and south, but the root are quite hardy, surviving into zone 5 (some varieties even into zone 3). Lift and replant your mint every 3 to 4 years to keep your patch’s flavor and scent strong.

How To Grow Mint

How To Grow Peppermint Mentha x piperita

Image Credit:
File: Mint-leaves-2007.jpg

Hardy perennial herbs of the Mint Family, Peppermint (Mentha x piperita) and Spearmint (Mentha spicata), grown for their leaves which are used to flavor vinegar and jelly (often served with roast lamb and other meats), and to enhance thirst-quenching cooling beverages.

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.


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.

Buy Mint Seeds

Spearmint Seeds

Spearmint is easy to grow and its leaves are popular in iced drinks, vegetables, lamb, and sauces.

How long does it take for mint sprouts to grow true leaves?

I have never grown mint from seed. I always get a little start instead. But I was pleasantly surprised you planted them in small pots! That is usually the biggest mistake.

What I am seeing is too much water. Part of a healthy soil environment is air and drainage is critical. Not just having a hole at the bottom is enough however. The roots of the plant need to fit the amount of soil. Those tiny sprouts are doing nothing to suck up water. Stop watering so deeply for starters. Just concentrate on keeping the surface moist, moist not soggy. Those plants aren’t using the water below 1/4 inch of the surface. I use a spray bottle to moisten the seed bed in pots that are 1″ X 2″.

Have you fertilized? Hopefully not, yet. Wait until they get their 3rd set of leaves and use a bit of OSMOCOTE 14-14-14. Only use a pinch and when you up pot don’t use anymore…just transfer the pinch along with your plants and soil into the new soil. When they get 6″ high give them another pinch. This last pinch should last 3 months. Mint is voracious and grows quickly. We can help you decide whether or not and when your plants need more. Just be very sparing. The seed has energy enough to get them started.

I need to know what soil you’ve used. Hopefully it was potting soil but sometimes potting soils have added stuff that really shouldn’t have been added; fertilizer and those water holding gels/sponges. Could you check? Take a picture of the bag, both sides to send?

Stop watering every day and just use a spray bottle to keep the surface moist. You might have to transplant with fresh soil to get rid of the soggy soil. No fertilizer, need to know if they put fertilizer in that soil. If there are water holding gels/sponges I’ll talk you into getting some plain old potting soil without!

Light? I’d use a south facing window, not east. Because a plant is genetically voracious and grows fast it needs some serious photosynthesizing and the first ingredient is light, the next is moisture and then properly balanced fertilizer but always on the spare side. Do you have a covered porch? I’d take these guys outside on the covered porch and let the wind and higher temperatures dry up your soil. Your soil might just be too wet but for now let’s see how they do. It takes time but this is the slowest LOOKING part of a mint’s life so enjoy it while you can! Keep your babies out of direct sunlight but they need lots of light. Are these to become indoor plants? What are your thoughts? Where is it you live? Do you have a garden, a yard? Mint can most certainly get out of control but if one is out poking and pruning and fussing in their garden often, this just won’t happen.

If you want your mint to be planted out in your garden you’ll need to acclimate it to the sun FIRST. This is done by gradually increasing the time in the sunlight. We can lead you through that. But if these are to be indoor plants let’s stay in a south facing window and/or a covered porch. Summer time I always take my indoor plants out on a covered porch to get better light so they can make more food for themselves, get hosed down of dust, and when they come back inside for the winter they look brand new. Please keep us updated as you grow your mint…so important to have successes so that you’ll continue to ‘grow’ as a gardener!

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