If your herbs keep dying, it's almost never you being "bad with plants". It's usually one of a handful of specific, fixable mistakes — most of them baked in before you even got the pot home. Here's what's actually going wrong, and what to do instead.
01Supermarket pots are set up to fail
That lush £1 basil isn't one plant. It's dozens of seedlings force-grown fast, sown far too thickly, and already running out of root room by the time it reaches the shelf. The RHS is blunt about it: those pots "usually contain lots of thin, overcrowded plants that tend to succumb to fungal diseases" — but they "may survive if divided up and repotted promptly."
So on day one: tip the plant out, gently tease the rootball into three or four clumps, and pot each one into fresh compost with a bit more space. Don't drown them while they settle. You've just turned one doomed pot into several plants with a fighting chance.
02Basil wants warmth, light and even moisture
Basil isn't hardy here — it "needs warm conditions" and "dislikes cold, damp conditions", says the RHS. A cold windowsill and a heavy hand with the watering can are what kill most plants.
Give it the brightest, warmest spot you have. Keep the compost evenly moist, but water in the morning rather than at night — basil hates having wet roots overnight, which is exactly how fungal rot sets in. And keep picking: take a few shoot tips from each plant to encourage bushy growth, and pinch off any flower buds the moment they appear. Let it flower and it stops making the leaves you want. More on basil.
03Coriander bolts — so stop transplanting it
Coriander doesn't die so much as give up: in hot, dry spells it "will stop producing leaves to concentrate on setting seed". Root disturbance triggers the same panic. That's why moving a supermarket pot on, or transplanting seedlings, so often ends in a flowering stalk and nothing to eat.
The fix, straight from the RHS: "Coriander dislikes being transplanted... so sowing your crop directly outdoors is the best option." Sow direct where it's to grow, in a cooler spot out of the fierce midday sun, and water in dry spells to delay flowering. Sow a small pinch every few weeks — successional sowing — so a fresh batch is always coming through, and pick often, because regular harvesting encourages more leaves.
04Mint: brilliant, but keep it in a pot
Mint is the opposite problem — it thrives so well it becomes a menace. Grow it in open ground and its underground stems (rhizomes) run everywhere; it can even re-grow from small pieces left in the ground. The RHS advice is simply to grow it in a container "to prevent the underground stems spreading into surrounding soil."
Keep the compost evenly moist — mint likes more water than the Mediterranean herbs below — and pick the young shoot tips regularly. The more you pick, the more you get. More on mint.
05Rosemary, thyme and sage die from wet, not cold
This is the big one. People assume these tough-looking shrubs succumb to a hard winter. They don't — they drown. All three are sun-loving Mediterranean plants that want full sun and sharp drainage.
- Rosemary hates having wet roots, especially in winter, and needs light, free-draining soil. It's hardy across much of the UK — it's the wet, not the cold, that finishes it.
- Thyme is drought tolerant and rarely needs watering; its roots will rot in damp conditions, especially in winter.
- Sage wants free-draining soil that never gets waterlogged.
Plant them in gritty, free-draining compost (add up to a quarter horticultural grit), in full sun, in a pot with plenty of drainage holes if your soil is heavy. And go easy on feed: in the ground these herbs should thrive even in poor soil. Overfeeding gives you soft, floppy, flavourless growth — the opposite of what you want.
Here's the honest bit. You do not need a self-watering smart planter, a hydroponic countertop unit or a grow-light kit to keep herbs alive. Almost every herb death above comes down to three free things: enough light, the right amount of water, and picking regularly. A bright, sheltered windowsill and a bit of restraint with the watering can will beat most kit on the market. Spend the money on decent peat-free compost and a bag of grit instead — that's what actually moves the needle.
How we checked this
Every care and safety claim on this page is verified against horticultural and veterinary sources.
Sources: How to grow basil — RHS · How to grow coriander — RHS · How to grow mint — RHS · How to grow rosemary — RHS · How to grow thyme — RHS · How to grow sage — RHS
Checked 19 July 2026. If our advice ever conflicts with the RHS, believe them and tell us.