How to Grow Mint in the UK

The first thing anyone needs to know about growing mint in the UK is also the thing that nearly nobody tells you until it is too late. Mint, if you let it, will take over an entire flower bed in two years. I learned this the hard way in my second proper growing year in Oxfordshire. I planted a small clump of spearmint in a corner of a herb bed because it looked tidy and the catalogue said it would “spread happily”. Three summers later that one little plant had colonised about four square metres of bed and was sending runners under the lawn into the neighbour’s garden. Digging it out took most of a weekend and I still found bits coming up two years afterwards.

So that is the headline news. Grow mint in a pot, every time, no exceptions. This guide covers how to do that properly, plus everything else you need to know about growing mint in the UK. The varieties worth choosing, how to grow it from seed (and why most people should not bother), and how to keep it productive from spring through to the first frosts.

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Why Mint Should Always Live in a Pot

Mint spreads by underground runners called stolons. These look like white roots but they are actually horizontal stems that travel along under the soil, popping up new plants wherever they fancy. A healthy mint plant can send a runner half a metre or more in a single growing season. By the second year you have a clump three times the size. By year four, you have a mint problem.

A pot stops this dead. The runners have nowhere to go, so the plant stays where you put it. It is the simplest gardening rule there is, and almost every UK gardener who has been at it long enough has the same story about ignoring it once and regretting it.

There is one workaround if you really want mint in a bed. Sink a deep pot or bucket into the ground, with the rim sticking up an inch or so above soil level, and plant the mint inside that. Cut off the bottom of the pot or leave it on (mint roots are not deep). The pot acts as a barrier and the rim above the surface stops runners escaping over the top. Even then, check it every spring for escapees.

The Best Mint Varieties to Grow in the UK

People often forget that mint is not one plant. There are dozens of varieties, all with different flavours and uses, and choosing the right one matters more than people realise.

Spearmint (Mentha spicata)

The classic mint for cooking. Sweet, mild, the one you want for new potatoes, lamb, salads, and traditional mint sauce. If you grow only one mint, grow this. Easy, vigorous, and reliable.

Peppermint (Mentha x piperita)

Stronger and more menthol than spearmint, with darker leaves and a hint of purple in the stems. The best mint for tea. Slightly less vigorous than spearmint but still wants its own pot. Worth growing alongside spearmint, not instead of.

Moroccan mint (Mentha spicata ‘Moroccan’)

A type of spearmint, narrower leaves, very fragrant. This is the one for proper Moroccan tea and it has a slightly more complex flavour than ordinary spearmint. My personal favourite for cold drinks in summer.

Apple mint (Mentha suaveolens)

Soft, fuzzy leaves with a fruity, almost apple-like scent. Less harsh than spearmint, lovely in jellies and desserts. Looks beautiful but worth saying it is just as invasive as the others.

Chocolate mint (Mentha x piperita ‘Chocolate’)

A peppermint variety with a genuine hint of chocolate in the smell. More of a novelty, brilliant in iced drinks and puddings. Grow one pot for fun.

If you are buying mint plants from a garden centre, the labels are sometimes vague (just “mint” with no variety). Specialist nurseries and seed companies like Suttons or Thompson and Morgan sell named varieties properly labelled, which is worth the extra trouble.

Growing Mint Outdoors in the UK

Mint thrives outdoors in most UK gardens. It is hardy, tolerates our climate beautifully, and actually prefers cooler conditions to hot Mediterranean ones. The main rules are simple.

Where to put the pot

Mint likes part shade more than full sun, particularly in southern England. A spot that gets morning sun and afternoon shade is ideal. It tolerates full sun but the leaves can get tough and the plant runs to flower faster in hot dry conditions. Mint will also tolerate quite shady spots better than most herbs, which makes it useful for those corners where nothing else seems to thrive. How to grow herbs in the UK covers more on which herbs suit shady versus sunny corners.

Pot size and compost

Bigger is better. A 25 to 30cm pot is the minimum for a single plant if you want decent harvests. A pot smaller than that will get root-bound within a season and the plant will start declining. Use a standard peat-free multipurpose compost, nothing fancy. Mint is not fussy about soil. Peat-free compost in the UK covers how to choose, and best compost for vegetables walks through the brands worth buying.

Watering and feeding

Mint likes consistent moisture. Unlike rosemary or thyme, it does not want to dry out between waterings. Check the pot every few days in summer and water when the top inch of compost feels dry. How often to water plants in the UK covers the wider principles.

Feeding is barely necessary. A light liquid feed once a month in summer is plenty. Too much feeding actually makes the leaves taste blander, because mint flavour is stronger when the plant is slightly stressed. Feeding vegetables properly in the UK covers the principle.

Growing Mint in Pots: The Best Setup

Since pots are the only sensible way to grow mint, it is worth getting the setup right. After twenty years of mint in containers I have settled on a few things that genuinely make a difference.

• One pot per variety. Mints crossbreed and the dominant one will eventually take over a shared pot, so spearmint, peppermint and apple mint all want separate homes.
• Pots up off the ground. Mint runners can escape through the drainage holes and into the soil below if you sit a pot directly on a flower bed. Stand mint pots on paving, on pot feet, or on a hard surface.
• Refresh every two years. Mint quickly exhausts its compost and becomes root-bound. Tip the plant out every other spring, split the root ball with a sharp spade, plant the healthiest half back into fresh compost and bin or give away the rest.
• Cut back hard in autumn. Once growth slows in October, cut everything back to 2 or 3 cm above the compost. The plant rests over winter and bounces back stronger in spring.

If you grow several herbs in containers, growing vegetables in pots in the UK covers the wider container principles, and the best vegetables to grow in pots includes herbs that work well alongside mint.

Growing Mint Indoors on a Windowsill

Mint will grow indoors but with mixed results. Honestly, of all the kitchen herbs, mint is the one I would put outdoors before in. It is hardy enough that it does not need indoor protection in any UK garden, and it grows much better with proper outdoor light.

That said, if you only have a windowsill, a kitchen ledge with bright light works. Choose a south-east or south-facing window, keep the soil moist (mint dries out faster indoors than out), and rotate the pot every few days so it grows evenly rather than leaning toward the light. The plant will be slightly leggier than an outdoor one, with paler leaves, but it will give you fresh mint when nothing is growing outside.

The best indoor approach for most people is to grow it outside through the summer, take a cutting in autumn, and grow that cutting on a windowsill for winter use. That way you get the strong outdoor flavour for most of the year and a smaller indoor plant for the dark months.

Growing Mint from Seed in the UK

Here is the honest truth. Do not bother growing mint from seed. I know that is the opposite of what most beginner guides say, but two decades of UK gardening have taught me there is no reason to do it.

The reasons are simple. First, seed-grown mint plants are weak and variable. Mint hybrids in particular (peppermint, chocolate mint, ginger mint) are sterile or unreliable from seed, so you cannot grow the named varieties at all. Second, you can get a small starter plant of any mint variety for £3 to £5 at any garden centre or nursery in spring, and one plant will give you cuttings to make many more for free within a few weeks. Third, growing mint from seed takes 8 to 10 weeks before you have a useful plant. Buying or propagating a cutting gives you a usable plant in 2 to 3 weeks.

If you genuinely want to grow mint from seed (some gardeners just like the satisfaction), sow shallowly into a tray of seed compost in March or April, keep on a warm windowsill, and pot up seedlings when they have 4 to 6 leaves. The wider technique is the same as everything else in how to grow vegetables from seed in the UK.

Propagating Mint from Cuttings (the Easy Way)

Mint is probably the easiest plant in the world to propagate. If you only learn one piece of plant propagation, learn this, because it will save you years of buying plants and give you free mint forever.

• Cut a healthy 10 to 15cm stem from an existing plant, just above a leaf node.
• Strip the bottom two thirds of leaves off, leaving 2 to 4 leaves at the top.
• Put the stem in a glass of water on a windowsill.
• Within 7 to 14 days, white roots will appear from the stem underwater.
• Once the roots are 2 to 3cm long, pot the stem into compost.

That is it. Genuinely. One mint plant can give you twenty new plants in a summer. Once you have grown mint this way you will never buy another mint plant again. It is also a brilliant project for getting children interested in gardening because the roots are visible and grow fast enough to keep them engaged.

Harvesting Mint to Keep It Productive

The single best thing you can do for a mint plant is harvest it hard and often. Mint that is left to grow becomes leggy, woody at the base, and runs to flower, after which the leaves lose flavour. A mint plant that is cut back regularly stays bushy, productive, and tender all season.

I cut my mint back by a third at least once a month through the growing season, even if I do not need that much. The cuttings get dried, frozen in ice cube trays with water, or given away. Cutting just above a leaf node makes the plant branch out at that point, doubling the new growth.

If you spot flower buds forming, pinch them off straight away. Once mint flowers, the leaves taste noticeably worse. The flowers themselves are pretty and the bees love them, so if you have multiple plants, let one flower for the pollinators and keep the others cropping.

Mint Through the Seasons

Spring (March to May). New shoots appear from the base. Buy or pot up new plants now. Start harvesting from established plants as soon as they have enough leaves. What to sow in May in the UK covers the wider sowing window.

Summer (June to August). Peak production. Cut hard and often, take cuttings, watch for flowering. June gardening jobs in the UK covers everything else this month, and what to plant in June includes herbs you can add now.

Autumn (September to November). Growth slows. Take final cuttings, dry or freeze leaves for winter use, cut the plant back hard before the first frosts.

Winter (December to February). Mint dies back completely above ground. Do not panic, this is normal. The roots are alive and the plant will return in March. Leave the pot somewhere outdoors but sheltered if possible.

Common Mint Problems

Mint is one of the most trouble-free plants you can grow, but it does have a few specific issues worth knowing about.

• Mint rust. Orange or rusty spots on the underside of leaves. Caused by a fungus, usually in humid weather. Cut all affected leaves off, bin them (do not compost), improve airflow around the plant. Mint rust can persist in the soil so a badly affected plant is sometimes best replaced.
• Spider mites or aphids. Occasional pests, particularly on stressed indoor plants. A spray with diluted soapy water usually sorts it.
• Leggy growth. Almost always too little light, or not enough harvesting. Move to brighter conditions and cut back hard to encourage bushy new growth.
• Plant declining over time. Compost exhausted or pot too small. Repot into fresh compost in a slightly bigger container.
• Mint escaping into your beds anyway. Check the bottom of the pot. Runners can creep out drainage holes. Lift the pot, trim escaping roots, sit the pot on a hard surface or pot feet.

Slugs and snails are not generally a mint problem. The strong oils actually deter them, which is one reason some gardeners plant mint near lettuce and brassicas to discourage them. How to get rid of slugs in the garden covers the methods that actually work elsewhere.

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Common Questions About Growing Mint

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A Sensible Place to Start

If you have never grown mint before, here is the plan. Buy one small spearmint plant from a garden centre in spring. Repot it straight into a 30cm pot of fresh peat-free compost. Stand the pot somewhere it gets morning sun and afternoon shade, not directly on a flower bed. Water when the compost feels dry an inch down. Start harvesting once the plant has 20 or more healthy leaves, and harvest hard at least once a month after that.

That single plant will give you fresh mint from April to October in its first year, and a near-endless supply of cuttings to grow more if you want them. After 20 years of growing mint in Oxfordshire, that is genuinely all there is to it.

If you want to build a wider herb collection, how to grow herbs in the UK covers the full picture, and how to grow parsley in the UK walks through the other essential kitchen herb in detail. Gardening for beginners in the UK covers the wider first-year approach if you are just starting out.