Grow fresh herbs on a small kitchen windowsill

Why a kitchen windowsill is a proper growing space

A windowsill is not a compromise. It is a small, warm, well-lit patch that you walk past twenty times a day, which means you notice problems early and actually use what you grow. For anyone in a flat, a terraced house or a rented place with no garden, it is the difference between buying a sad plastic punnet of basil every fortnight and snipping your own leaves into a pan of tomatoes on a Tuesday evening.

The trick is to work with what you have rather than against it. A south or west-facing sill will give you the widest choice. East is perfectly workable. A north-facing kitchen window is the hardest spot, but chives, mint and parsley will still tick along there, especially between March and October. Measure your sill before you buy anything: 15–20cm pots are the sensible maximum for most windowsills, and you will fit more herbs in if you choose compact varieties rather than the big bushy ones sold for garden beds.

Choose herbs that suit a small pot

Not every herb enjoys life indoors. These are the ones that earn their place on a narrow sill:

• Basil. Look for bush or Greek types rather than large-leaved sweet basil, which grows tall and flops. A single plant in a 15cm pot is plenty.
• Mint. Superb in a pot, but it must have its own. It spreads by runners and will swamp anything beside it within a season.
• Chives. The most forgiving herb on this list. They tolerate lower light, regrow quickly after cutting and look tidy while they do it.
• Parsley. Slow to start, then generous for months. Flat-leaved has better flavour; curly holds its shape on the plate.
• Thyme and marjoram. Fine on a sunny sill, but they need sharp drainage, so add extra grit to the compost.

Skip rosemary, bay and large oregano. They want more root room, more light and, frankly, a garden. If you buy a supermarket pot of basil or parsley, do not keep it as it comes. Those pots hold a dozen seedlings crammed together. Split them gently into two or three pots of peat-free multipurpose compost and you will get far more leaf for far longer.

Light is the limiting factor, not space

Aim for six hours of direct light a day. In a UK winter, that is a big ask, so squeeze out every hour you can. Turn each pot a quarter turn once a week so the stems grow straight rather than leaning into the glass. If your sill faces away from the sun, stand a piece of white card or foil behind the pots to bounce light back onto the leaves.

Two warnings. First, do not sit herbs directly above a radiator: the rising warm air dries the compost from below and cooks the roots. Second, on frosty nights the glass itself gets bitterly cold, so move pots 10cm back from the pane or draw a curtain between plant and window.

If a plant starts stretching into thin, pale, gap-toothed stems, it is telling you it wants more light. Pinch the leggy growth back and move it to a brighter spot.

Watering carefully is the real skill

More windowsill herbs are killed by kindness than by neglect. Small pots dry out fast, but sodden compost is far more damaging than a brief drought. Check before you pour: push a finger to the first knuckle into the compost, or simply lift the pot and feel its weight. Light means water.

• Water in the morning, so surplus moisture has the day to evaporate.
• Water from below where you can, standing the pot in a saucer of water for twenty minutes, then emptying whatever is left.
• Never leave pots sitting permanently in water. Roots need air as much as moisture.
• Water far less from November to February. Growth has slowed and the compost stays damp for days.

Terracotta dries out faster than plastic, which suits thyme and marjoram but not thirsty mint. Grouping pots on a tray of damp gravel raises humidity around the leaves and helps basil through the dry heat of a centrally heated kitchen.

Feed, pinch and keep the leaves coming

Once plants are established, a weak liquid feed every two to three weeks through spring and summer keeps leaves tender and productive. Use roughly half the strength recommended on the bottle and stop entirely over winter.

Harvesting is what keeps herbs bushy. Pinch out the growing tip of basil just above a pair of leaves and two new shoots will break from that point. Chives can be snipped down to about 2cm and will regrow within a fortnight. Take no more than a third of any plant at once, and always cut above a leaf joint rather than into bare stem.

Replace, rather than nurse, the short-lived ones. Coriander bolts and gives up within a few months, so sow a fresh pot every three weeks and you will never be without it. Basil behaves similarly in low light: take cuttings in late summer, root them in a glass of water, and pot them up for the darker months ahead.

Getting through the cooler months

Expect less. From October to February your herbs are surviving rather than thriving, and that is normal. Move everything to the brightest sill in the house, cut back on water, and resist the urge to feed. Chives, mint and parsley will usually hold on. Basil often sulks and drops leaves; treat it as an annual and start again in spring.

Watch for a dusty green film on the compost surface, a sign of mould from cold, wet roots, and for small black flies, which means the compost is staying too damp. Scrape off the top centimetre, let the surface dry between waterings and the problem usually clears. A faded, straggly windowsill in January is not failure. It is a pause, and by March you will be snipping fresh leaves again.