How to Grow Supermarket Mint Forever in a Glass of Water

Supermarket mint is usually the biggest disappointment: aromatic on the first day, then miserable by the weekend. A gardener showed me how to reverse that pattern by growing the very same stems indefinitely in a simple glass of water.

It started at 5 p.m. on a crowded kitchen worktop, in the sort of late-afternoon light that can make even a chipped mug seem cinematic. A retired landscaper I had met at the market took a bunch of mint from its plastic packet, cut it with kitchen scissors and placed the stems in a transparent tumbler. There was no rooting powder and no compost-only water, accompanied by a shrug that seemed to say, “Watch.” Within a week, fine pale strands emerged from the nodes like miniature fireworks. We sampled the leaves, which tasted as fresh as though they had grown on a hillside. The glass had done all the growing.

Turn a limp bunch into endless mint

Mint is eager to survive. That is the understated secret of this method: the plant is naturally ready to send out roots from any node exposed to moisture. Put several supermarket sprigs in water and, within days, they begin a new phase-first a soft callus appears, followed by roots, then fresh new leaves that look better than those in the original bunch.

I once tracked a batch bought during a late-night supermarket visit. By the fourth day, small root buds were visible; by the eighth, there were established roots. After two weeks, the stems were producing new shoots, giving me enough to cut for tea without feeling wasteful. One £1.50 bunch provided a reliable supply for eight weeks, with three glasses in rotation and no soil anywhere.

The explanation is straightforward plant biology. The small bumps on the stem, known as nodes, already contain dormant growth tissue. Give them clean water, oxygen and light, and they produce adventitious roots. Keep the glass at room temperature in bright, indirect light, and the mint directs more energy into rooting than wilting. Cleanliness does much of the work.

The glass-of-water mint method, step by step

Choose the freshest stems in the packet: they should be firm, green and carry intact leaves. Cut the bottom of each stem at a slight angle just beneath a node, then remove the lower leaves so that none are beneath the water. Add 3–4 cm of water to a clear glass and place 5–7 stems inside, leaving them enough room.

Set the glass close to a bright window where it receives soft light. Replace the water every two or three days rather than relying on guesswork, and rinse the glass whenever it turns cloudy. Roots generally appear after 5–10 days, while tips can be harvested after 10–14 days. Bright, indirect light is preferable to a hot windowsill that scorches the leaves at midday.

Common mistakes include cramming in too many stems, allowing leaves to sit in water, using strongly chlorinated water or leaving mint in direct sunshine, where the tumbler becomes a miniature sauna. Everyone knows that moment when the water becomes swampy and the guilt sets in. Honestly, no one manages it every day. Aim for “often enough” instead: change the water before the weekend, give it a quick rinse midweek, and you should be fine.

“Treat the water like air,” the gardener told me. “Fresh, clear, moving. Do that, and mint behaves like it’s got a second life.”

• Change the water every 2–3 days to maintain oxygen levels and prevent unpleasant build-up.
• Cut beneath a node to ensure the cut surface remains clean and ready to root.
• Limit each glass to 5–7 stems, avoiding overcrowding and slime.
• Turn the glass regularly so every side receives light; mint naturally leans towards the sun.
• Once roots reach 3–5 cm, pot up some stems and restart cuttings for the following batch.

Endless mint without making it a chore

This is where it becomes particularly useful: one glass of rooted mint becomes a small mint factory. Pinch off the tips when harvesting, then use those fresh tips as the next generation of cuttings. When the roots become dense and rope-like, divide the batch-put half into a pot as a backup and leave the other half in the glass to keep the worktop green. This is the little green trick that never gets old. Give a few rooted stems to a neighbour, bring some on a picnic, or place them in a jar on your desk and watch colleagues gather around like bees. The cycle could not be simpler: cut, sip, repeat. Water restarts the process, while the plant takes care of everything else. On an ordinary Tuesday, when dinner needs rescuing, two leaves stirred into yoghurt or crushed into peas can change the whole dish-without an emergency trip to the supermarket.