How to Grow Mint: A Practical Guide from Seed to Harvest

Mint is one of the easiest and most useful herbs to have around the garden. Once established, it grows rapidly, produces plenty of fresh leaves and comes back year after year.

In fact, with mint the problem is rarely getting it to grow. It's usually persuading it to stay where you put it.

That's why I particularly like growing mint in pots. It keeps the roots contained, you can put a pot somewhere convenient near the kitchen, and you're much less likely to discover a few years later that mint has quietly taken over of half the border.

Mint is a perennial, so plants die back or become much less productive during winter before producing fresh new shoots again in spring.

It's straightforward to grow from seed, although germination and early growth take a little patience. Once the plants get established, you'll have considerably less trouble persuading them to grow.

Give mint reasonable moisture, sun or partial shade and plenty of room to develop.

When to Sow

Mint can be sown from February to June, with spring being the easiest time to get plants established.

I prefer starting mint in pots or trays somewhere warm rather than sowing directly outside.

March and April are particularly useful months because the days are getting longer and young seedlings have plenty of time to develop before summer.

You can start earlier on a warm, bright windowsill or in a propagator.

There's no need to rush, though. Mint is a perennial, so you're establishing a plant that could be with you for years rather than trying to get one quick crop.

Later spring sowings will soon catch up once conditions warm.

How to Sow

Mint seed is very small, so it doesn't need to be buried deeply.

Fill a pot or seed tray with seed compost and gently firm the surface. Water the compost before sowing and allow any excess to drain.

Sprinkle the seeds thinly over the surface.

Cover them with only a very fine layer of compost or vermiculite, or gently press them onto the surface.

Keep the compost moist but not soaking wet and put the tray somewhere reasonably warm.

Germination can be a little uneven, so don't give up if everything doesn't appear at once.

Once seedlings emerge, give them plenty of light.

Growing Seedlings On

Let the seedlings develop until they're large enough to handle comfortably.

If they're badly crowded, carefully move them into individual small pots or separate small groups.

Keep young mint somewhere bright and keep the compost reasonably moist.

Unlike thyme and sage, mint doesn't particularly enjoy being kept dry. It naturally prefers slightly moister conditions.

As the plants develop, pinch out the growing tips occasionally to encourage bushier growth.

Move plants into larger pots as their roots fill the existing container.

Before planting outside, harden off plants that have been raised indoors or under cover.

Don't worry if seedlings seem slow initially. Once mint develops a decent root system, growth will get stronger.

Growing Mint in Pots

If I had to recommend one way to grow mint, I'd put it in a pot.

Mint spreads through underground stems and can travel surprisingly far once it's established in open ground. A container keeps that growth under control and makes the plant easier to manage.

Choose a pot with drainage holes and give the plant enough room to develop. Something around 25–30cm across is a sensible starting point for an established plant.

Use good-quality multipurpose compost and place the pot in sun or partial shade.

Mint appreciates regular moisture, so a good size pot will help in the heat of summer.

As the plant fills the pot, you can divide it and replant a younger section into fresh compost.

One thing to watch is mint escaping through the drainage holes. Put a pot directly onto garden soil for long enough and the plant will quickly spread in the garden

A patio or pot feet are a good option.

Planting Mint in the Garden

You certainly can grow mint in the ground, but choose the position carefully.

It grows well in sun or partial shade and appreciates soil that holds some moisture without being permanently waterlogged.

The bigger consideration is its spreading habit.

If you want to grow mint in a border, you can sink a large container into the ground to restrict the roots. Leave the rim slightly above soil level and keep an eye out for stems trying to escape over the top.

Alternatively, give mint an area where spreading isn't going to cause a problem.

Watering and Feeding

Mint appreciates regular watering, particularly when you're harvesting lots of fresh growth.

Plants in containers need checking frequently during warm weather because a large leafy plant can use a surprising amount of water.

Keep the compost reasonably moist, but don't leave pots permanently standing in water.

Mint growing in the ground is less demanding once established, although it will appreciate a thorough watering during prolonged dry spells.

Container plants may benefit from an occasional general-purpose liquid feed during spring and summer.

You don't need to feed excessively. Mint is naturally vigorous.

Refreshing some of the compost or dividing an overcrowded plant can sometimes do more good than repeatedly adding fertiliser.

Harvesting

Start harvesting once the plants are established and producing plenty of leafy growth.

You can pick individual leaves, but I prefer cutting whole young shoots just above a pair of leaves. This encourages the plant to branch and produce more fresh growth.

Pick regularly throughout spring and summer.

If you need quite a lot of mint, don't be afraid to cut an established plant fairly hard during the growing season. It usually responds by producing a fresh flush of shoots.

The youngest leaves tend to have the nicest texture.

Mint is best used fresh, but leaves can also be dried or frozen if you've got more than you can use.

Having a pot near the kitchen is particularly handy. Mint is one of those herbs where being able to walk outside and snip what you need is half the reason for growing it.

Flowering and Wildlife

Mint usually begins flowering during summer.

The flowers are very popular with bees, hoverflies and other pollinating insects, so I like to let at least some stems flower.

If your main priority is producing lots of young leaves, you can cut some flowering stems back and encourage fresh growth.

Once flowering has finished, an established plant can be cut back if it's becoming untidy.

It will often produce another flush of fresh leaves if there's enough growing season left.

Dividing Mint

Mint is easy to divide and it's worth doing every few years, particularly with container plants.

An old pot can become packed with roots and start producing less attractive growth.

In spring, remove the plant from its container and divide the root mass into several sections.

Choose a healthy younger section and replant it into fresh compost. The remaining pieces can be planted elsewhere, potted up or passed on to someone who hasn't yet discovered quite how much mint one plant can produce.

Common Problems

Mint Rust

Mint can sometimes develop rust, which appears as orange, yellow or brownish spots on the leaves.

Remove affected foliage and avoid overcrowding plants. If a container plant is badly affected, cutting it back and encouraging fresh growth can help.

Don't put badly diseased material into home compost if you're concerned about spreading the problem.

Powdery Mildew

A white powdery coating can develop on leaves, particularly when plants are stressed, overcrowded or repeatedly allowed to dry out.

Keep mint watered, give plants reasonable airflow and remove badly affected foliage.

Aphids

Aphids can gather around soft young shoots.

Small colonies can often be washed away or rubbed off. Plenty of beneficial insects visit flowering mint too, so natural predators often help.

Yellowing Leaves

Older leaves naturally yellow, particularly towards the base of a dense plant.

More widespread yellowing can result from waterlogging, exhausted container compost or a badly overcrowded root system.

Check the pot before automatically adding more feed.

Mint Taking Over

This is perhaps mint's most predictable problem.

If it's spreading where you don't want it, dig out wandering roots as soon as you notice them.

Growing mint in a container from the beginning is considerably easier than trying to remove it from a border several years later.

Plant Disappearing in Winter

Don't panic if your mint seems to vanish when the weather turns cold.

Mint is perennial but usually dies back during winter. Cut away dead growth and wait. Fresh shoots should begin appearing again in spring.

Mint is one of those herbs where a pot really does make life easier. Give it regular water, pick it often and divide it when it becomes crowded. You'll get plenty of fresh leaves without having to work very hard for them — and, importantly, you'll have a fighting chance of keeping the mint on your patio rather than eventually finding it halfway across the garden.