How to Grow Mint in a Pot Without It Taking Over

Mint grows in gardens and on balconies from Morocco to Mexico, and almost everyone who plants it learns the same lesson. One small plant set loose in a bed can turn into a carpet of runners within a couple of seasons, popping up among your other herbs and under paving.

The good news is that mint is happy in a pot, and a pot keeps it exactly where you want it. Here is how to grow mint at home, harvest it well and stop it from taking over the garden.

Why mint spreads, and why a pot is the answer

Mint spreads by underground stems called rhizomes. University of Illinois Extension describes it as aggressive and potentially invasive, and Utah State University Extension warns that once it is established in open ground it is very hard to get rid of.

Both recommend confining the roots. The Royal Horticultural Society (RHS) says mint is best grown in a pot rather than in the ground. If you want it in a bed, sink a container into the soil and leave the rim slightly above the surface, so that creeping shoots cannot root over the edge. Utah State suggests a buried container that reaches 25 to 38 cm (10 to 15 inches) deep, with 8 to 10 cm (3 to 4 inches) standing above the soil.

Sun, compost and water

Mint grows in full sun or partial shade. Variegated types, such as pineapple mint, can scorch in strong sun, so give them some afternoon shade. Use a peat-free multipurpose or soil-based compost, and choose a pot with drainage holes.

Potted mint dries out much faster than mint in the ground, so check it often in summer and keep the compost evenly moist. In a heatwave, moving the pot into light shade cuts down on watering. Avoid soggy compost and wet leaves overnight. Utah State notes that overwatering and too much fertilizer encourage mint rust and reduce mint oil, so go easy on both.

Picking, cutting back and dividing

Start picking once stems are about 8 to 10 cm (3 to 4 inches) tall. The young, soft tips have the most flavor, and frequent picking keeps the plant bushy. Pinch off flower spikes as they appear: Illinois Extension advises this to keep the leaves' flavor. If the plant does flower, the RHS suggests cutting the whole thing back to about 5 cm (2 inches) from the base: fresh leaves follow within a few weeks.

Mint dies back in winter. Cut the old stems down any time from late autumn to early spring. Every few years the roots fill the pot and growth slows. Then divide the clump in spring or autumn: slice the rootball into sections, throw away the old, woody middle and replant the healthy pieces in fresh compost. Illinois Extension suggests dividing every three to four years.

What the evidence says

On containment, the extension services agree on the basics but differ on details. Illinois Extension considers raised, above-ground pots more reliable than sunken bottomless ones, because roots can sometimes escape a buried container. So if mint must be in a bed, check the edges each season and pull any runners that slip out.

On seed, Utah State explains that mints cross with each other easily, so plants grown from seed often do not match the variety on the packet. If you want a particular flavor, such as a good spearmint for tea, start from a plant you have tasted, a cutting or a division instead. The RHS notes that stems placed in a jar of water root readily.

Questions people ask

This article is for general information only and is not medical advice. Herbs can interact with medicines and health conditions. Talk to a doctor or pharmacist before trying a herbal remedy, especially if you are pregnant, breastfeeding, giving it to a child, or taking any medication.