Starting a Kitchen Herb Garden on a Windowsill

Why a Windowsill Earns Its Keep

A sunny windowsill is the smallest productive patch in the house, and quite possibly the hardest working. Three pots of herbs will give you more cut-and-come-again leaves than a supermarket bunch, and they will still be fresh when you want them. There is also something quietly satisfying about snipping a handful of chives over scrambled eggs on a grey Tuesday in February.

The trick is to be honest about the conditions. A windowsill is not a garden. It has no wind, no rain, no worms, and a light source that comes from one direction only. Choose herbs that suit those constraints and you will succeed; fight them and you will be buying another sad pot of basil by Easter.

Pick Compact, Generous Croppers

Not every herb copes with indoor life, so start with three that genuinely do.

• Basil. Look for compact bush varieties rather than the tall, single-stemmed sort. Sweet Genovese is fine if you pinch it regularly, but a small-leaved bush type holds its shape far better on a sill. Basil hates cold and draughts, so keep it away from the window glass on frosty nights.
• Flat-leaf parsley. Slow to germinate and slow to get going, but once established it crops for months. It tolerates a little shade, which makes it the best choice for a north-facing sill. Buy a plant rather than seed if you want leaves this side of summer.
• Chives. Practically indestructible. They die back in winter, which alarms people, but the bulbs are simply resting and will push up fresh green shoots in spring. Snip from the outside of the clump and leave the centre alone.

Mint is tempting, but it runs. Keep it in its own pot or it will colonise everything else on the sill. Coriander bolts indoors within weeks unless you sow it little and often, so treat it as a cut-and-come-again crop rather than a permanent resident.

Deep Pots, Free Drainage, Sensible Compost

Herbs fail indoors far more often from waterlogged roots than from neglect. A deep pot gives roots room to stretch and holds moisture more evenly than a shallow saucer of compost. Aim for something at least 15cm across and 15cm deep for a single plant, and larger for a clump of chives.

Drainage is non-negotiable. Every pot needs holes in the base, and every pot needs a saucer beneath it if you value the paintwork. Add a layer of crocks or coarse grit at the bottom, then fill with a peat-free multi-purpose compost mixed with a couple of handfuls of horticultural grit. That grit does two jobs: it opens up the compost so roots can breathe, and it stops the surface sitting soggy.

If you are reusing old pots, scrub them first. Last year's compost can carry damping-off fungi that will see off a young basil plant in a fortnight.

Water Little and Often

This is the single habit that separates lush windowsill herbs from woody, sulking ones. Aim to keep the compost lightly moist, like a wrung-out flannel, rather than soaked or bone dry. Check daily by pushing a finger in up to the first knuckle; if it feels dry at that depth, water.

Small, frequent drinks beat a weekly drench every time. A drench saturates the lower compost, starves the upper roots of oxygen, and then dries out from the top down, so the plant swings from drowning to drought. Little and often keeps the root zone steady, which in turn keeps leaves tender rather than tough.

Water in the morning where you can, using water that has stood in the watering can overnight so it is not shockingly cold. Empty the saucer after half an hour, because standing water is how root rot starts.

Light, Feeding and Pinching

Turn your pots a quarter-turn every few days. Without that, stems lean hard towards the glass and you end up with a lop-sided plant that needs staking by March.

Feed sparingly. A dilute liquid feed every fortnight through spring and summer is plenty; overfeeding forces soft, sappy growth that flops and attracts aphids. In winter, stop feeding altogether and water much less.

Pinch out the growing tips of basil regularly, taking the top pair of leaves with your thumb and forefinger. Each pinch encourages side shoots, and each side shoot means more leaves. Never strip more than a third of the plant at once. Parsley and chives simply want the outer stems cut close to the base, which keeps the centre productive.

Harvesting for the Kitchen

Cut herbs in the morning, before the sun has drawn the oils out of the leaves, and use them quickly. Basil bruises if you chop it roughly, so tear it or slice it thinly and add it at the last moment. Parsley and chives both take well to being snipped straight over the pan with kitchen scissors.

Chives will give you a second harvest of edible purple flowers if you let a few buds open. Basil and parsley will keep going for months if you keep pinching and picking. Sow a fresh pinch of basil seed every six weeks in a small pot to fill the gaps, and you will have a windowsill that earns its place all year round.