Why a Windowsill Beats a Vegetable Patch

Anyone who has tried to keep a row of herbs going on an allotment knows the truth of it. By August the parsley has bolted, the mint has marched halfway across the bed, and you are still buying a plastic packet of basil from the supermarket. Pots solve nearly all of it. You control the compost, you control the water, and — best of all — the pot can sit a few steps from the stove, so a recipe that asks for a handful of thyme actually gets one.

Four herbs will cover the bulk of everyday cooking: basil, mint, thyme and parsley. Grown well in containers, they will keep you supplied from spring right through to the first hard frost, and in a sheltered kitchen they will often carry on beyond it.

Pots, Compost and the Right Spot

Size matters more than style. Basil and parsley want a pot around 20cm across and deep enough for a decent root run; mint is happiest in something similar; thyme prefers a shallower, wider pan, roughly 25cm across but only 15cm deep, which suits its creeping habit. Terracotta is lovely and dries out faster, which thyme appreciates and basil does not. Whatever you choose, drainage holes are non-negotiable — a few crocks or a scatter of grit in the base, and a saucer underneath to catch the overflow.

Use a peat-free multi-purpose compost for basil, mint and parsley, and mix in a good handful of horticultural grit for thyme. Thyme also likes lime, so a spoonful of garden lime or crushed eggshell in the mix does no harm at all.

Then think about light. A south- or west-facing windowsill gives the six hours of sun that basil and thyme need. Mint and parsley will manage quite happily on an east-facing sill. Do avoid the classic mistake of tucking basil above a sink in a shaded galley kitchen: the humidity encourages downy mildew, and the lack of light leaves you with pale, leggy stems.

Basil and Mint: The Thirsty Two

These two are the drinkers of the group. Basil germinates fast in warmth — sow seed in late spring, keep it at around 18–20°C, and pinch out the growing tip above a pair of leaves once the plant has three sets. That single pinch is what turns a spindly seedling into a bushy plant. Keep harvesting from the top and it will keep branching.

Mint has the opposite problem: it is almost too eager. Always give it its own pot, never share with anything else, or its runners will smother the neighbours within a season. Keep the compost steadily damp rather than soggy, and cut it back hard if it starts to look tired — it will bounce back within a fortnight. If you want mint through winter, bring a pot indoors in autumn before the first frost.

Thyme and Parsley: The Patient Two

Thyme is a Mediterranean plant doing its best in a British climate. Give it full sun, gritty compost and a little neglect. Let the compost dry out between waterings, water at the base rather than over the leaves, and go easy on feeding — rich compost makes soft, flavourless growth. Harvest with scissors, taking sprigs from the top, and replace plants every three years or so when they turn woody. Cuttings taken in late summer root easily and cost you nothing.

Parsley is slower and more forgiving. Soak the seed overnight before sowing; germination can take three to four weeks, so be patient. It has a long taproot, which means a deeper pot than you might think and no root disturbance — sow where it is to grow. Keep it moist and cut the outer stems right down at the base, never just the leafy tops, and the heart of the plant will keep producing. Remember it is a biennial: the second year it will run to flower and stop being useful, so sow a fresh pot each spring.

Watering, Feeding and the Daily Round

Poke a finger into the compost before you reach for the can. Damp at the second knuckle means leave it alone; dry means water thoroughly until it runs into the saucer, then empty the saucer after half an hour so the roots are not sitting in a puddle. Morning is the best time, and watering from below encourages roots downward.

Feed leafy herbs with a diluted tomato feed every fortnight through the growing season. Thyme can be left largely to its own devices. Watch for greenfly and whitefly on the soft new tips — a firm spray with water usually shifts them — and pinch out any flower buds on basil and mint as soon as they appear, because once a herb sets seed it puts its energy there instead of into leaves.

Cutting and Keeping the Harvest

Never strip more than a third of a plant at once. Regular, light cutting keeps herbs compact and productive; occasional heavy hacking leaves you with a sulky stump. Use scissors rather than fingers, which bruise the stems.

Surplus basil and parsley freeze beautifully, chopped into ice-cube trays and topped up with water or olive oil. Thyme dries well in a warm, airy cupboard and keeps its character far better than the dusty jars on the supermarket shelf. Between the four of them, a sunny sill and a little attention, your kitchen will smell like a cottage garden — and dinner will taste all the better for it.