Why the kitchen windowsill is such a good spot

A kitchen windowsill is, in many ways, the perfect small-scale growing space. It offers the two things herbs crave most: bright light and constant attention. A south- or west-facing sill that receives six hours or more of daylight will keep basil, mint, parsley and chives in genuinely useful production for months. Even a north-facing window can work for chives, parsley and mint through the summer, though basil will sulk and stretch towards the glass.

The other advantage is proximity. Herbs are only worth growing if you actually cut them, and a pot three steps from the chopping board gets picked far more often than one at the end of the garden. Frequent harvesting is not a threat to these plants — it is what keeps them bushy, leafy and productive. What follows is a practical guide to the four herbs that earn their windowsill space.

Basil: greedy for heat and constant pinching

Basil is the herb most people try first, and the one most often lost. It wants warmth (18–21°C is ideal), full sun and steady moisture, and it hates cold, wet roots and draughts.

If you buy a supermarket pot, do not leave it crammed together on the sill. Tip it out, gently tease apart the seedlings into three or four clumps, and pot each into a 9cm pot of peat-free multipurpose compost. Water from the base, letting the top centimetre of compost dry between drinks, and never leave the pot standing in water.

• Pinch out the growing tip above a pair of leaves once the plant has three pairs, and keep doing it. This is what turns a single stem into a productive bush.
• Harvest from the top, never more than a third of the plant at once.
• Feed with a dilute tomato feed every fortnight during summer.
• Sow successionally every six to eight weeks from March to August; basil is fast but short-lived.

Keep leaves dry and avoid cool nights — damp foliage in low temperatures invites downy mildew, which shows as yellowing patches and grey fuzz on the undersides. Below about 12°C, basil stops growing altogether.

Mint: vigorous, thirsty and best kept to itself

Mint is almost indestructible, which is both its charm and its problem. Given a shared pot, its runners will invade everything else. Plant it alone, always, in a pot at least 15cm across.

Spearmint is the best all-rounder for cooking, Moroccan mint makes superb tea, and apple mint is milder and excellent with peas and new potatoes. Mint is thirstier than basil — check the compost daily in hot weather, as it will flag dramatically within hours of drying out.

Cut stems back to a pair of leaves rather than snipping at the tips, and harvest from the top of the plant down. In midsummer, a position with a little shade from the strongest afternoon sun suits it better than baking heat. Watch for mint rust: orange-brown pustules on the leaves. Pick affected foliage off at once, cut the plant back hard and discard the debris in the bin rather than the compost heap. In spring, tip the rootball out, tease away the old compost and repot into fresh material to keep growth young and tender.

Parsley: slow to start, generous for months

Parsley tests your patience before it rewards it. Germination takes three to six weeks, so soak the seed overnight in warm water before sowing and be prepared to wait. Flat-leaved French parsley is the one for cooking; curly parsley is prettier but coarser in flavour.

Because it develops a long taproot, parsley needs a deeper pot than the others — 20cm or more. Cut the outer stems right down at the base rather than snipping the tips, and the heart of the plant will keep producing new growth. Feed fortnightly in summer, and keep the compost evenly moist but never soggy.

Parsley is a biennial, so a plant sown this year will run to seed next summer however well you treat it. Sow a fresh pot every few months to keep a steady supply. Aphids and celery leaf miner are the main nuisances; a firm jet of water from a spray bottle deals with most infestations on a windowsill without chemicals.

Chives: the hardiest of the four

Chives are the reliable one. Hardy, perennial and happy in a cool kitchen, they will crop for years from a single pot. Sow from March to May, or simply divide an established clump from the garden in spring and pot a section up.

Snip with scissors close to the base, leaving about 5cm of growth, and never pull at the leaves — tearing damages the bulb. Remove flower buds if you want maximum leaf, but do leave a few to open: the pink flowerheads are superb scattered over salads, stirred into soft cheese or steeped in white wine vinegar.

Chives benefit from a cold spell, so a pot that spends autumn and early winter outdoors and comes back to the sill in January will crop sooner and more strongly than one kept warm all year.

Keeping the windowsill productive

A few small habits make a real difference. Turn each pot a quarter turn every week so stems grow straight rather than leaning into the glass. Water in the morning, so any splashes on foliage dry before evening. Group pots together to raise humidity, but leave a little air moving between them to discourage mould.

Stand pots on saucers or a gravel tray, but keep the compost clear of standing water. Check new plants for pests before introducing them to your collection, and inspect leaf undersides weekly for aphids and whitefly. Finally, sow or pot on something new every few weeks. A windowsill that is constantly being replanted is a windowsill that never runs out of herbs.