Growing Herbs in Pots on a Windowsill

Why the Windowsill Is the Best Herb Bed in the House

Fresh herbs in January are one of the small luxuries of a British kitchen, and a sunny windowsill is the easiest place to grow them. Indoors, herbs escape the worst of our weather: no slugs, no wind damage, no waterlogging from yet another week of rain. What they cannot escape is the light.

Light is the single factor that decides whether your windowsill herbs flourish or sulk. A south-facing sill gives the most hours of direct sun and will happily support basil, rosemary and thyme. East and west-facing sills get good morning or afternoon light and suit parsley, chives, mint and coriander, though they may need a little help in midwinter. A north-facing sill is genuinely difficult — mint and parsley will survive there, but do not expect lush growth. Before you buy anything, spend a day noticing how many hours of direct sun your sill actually receives.

Which Herbs Genuinely Thrive in Pots Indoors

Some herbs take to indoor life beautifully; others resent it. These are the reliable performers:

• Basil — the classic windowsill herb. It loves warmth and light and will crop for months if you keep pinching it. It hates cold compost and draughts.
• Parsley — flat-leaved or curly, both are happy in a deep pot. Slow to germinate from seed, so buy a plant to start with.
• Chives — cheerful, undemanding and quick to regrow after cutting. Snip the leaves rather than pulling them.
• Mint — vigorous to the point of bullying, so give it its own pot. It will die back in winter and return in spring, which alarms new growers every year.
• Coriander — fast-growing and short-lived, best sown little and often. It bolts quickly in warmth, so keep it out of the hottest spot.
• Thyme, rosemary and oregano — Mediterranean herbs that need the sunniest sill you have and a gritty, free-draining compost. Water them sparingly.

Skip dill, chervil and tarragon for windowsill growing; they are fussy about light and rarely worth the space.

Pots, Compost and Getting the Basics Right

Choose pots with proper drainage holes — a decorative pot without holes will drown your herbs. Roughly 15cm across suits a single basil or parsley plant; thyme and oregano are content in 10cm pots. Always stand them on a saucer to protect your paintwork, and lift the pot occasionally so it does not sit permanently in water.

For leafy herbs such as basil, parsley, chives and mint, use a peat-free multi-purpose compost. For the Mediterranean group, mix it half and half with horticultural grit to keep it open and sharp-draining. Fill pots to about 2cm below the rim so you can water without it running straight off, and firm the compost gently around the roots.

If you buy a supermarket pot of basil, you will find a dozen seedlings crammed together. Divide it into three or four pots straight away, teasing the roots apart under a running tap. They will thank you for it.

Watering and Feeding Without Drowning Anything

Overwatering kills more windowsill herbs than anything else. The compost should be allowed to dry slightly between waterings — push a finger in to the first knuckle and only water if it feels dry at that depth. Basil will flop theatrically when thirsty and recover within an hour, which is a useful signal rather than a disaster.

• Summer: most pots need water every day or two in hot weather.
• Winter: once a week, sometimes less. Growth has slowed and the compost stays wet for far longer.
• Feeding: from March to September, give leafy herbs a weak liquid seaweed or tomato feed every fortnight. Mediterranean herbs need feeding only once a month, and not at all in winter.

A radiator directly beneath the sill creates a hot, dry microclimate. Move pots to a nearby shelf, or stand them on a tray of pebbles kept slightly damp to lift humidity around the leaves.

Keeping Plants Productive: Pinching, Succession and Pests

The more you cut, the more you get — up to a point. Pinch out the growing tips of basil regularly, taking the stem just above a pair of leaves, and it will branch into a bushy plant instead of a lonely stalk. Never strip more than a third of the foliage from thyme or rosemary at once; they regrow slowly from old wood.

Sow coriander and basil every three or four weeks in small batches for a continuous supply rather than one glut followed by nothing.

Watch for the usual suspects:

• Fungus gnats — tiny black flies rising from the compost mean it is too wet. Water from below, let the surface dry out, and top the compost with a layer of grit.
• Aphids — check the undersides of leaves and new shoots. A firm jet of water dislodges them; repeat every few days.
• Whitefly — a cloud of tiny white insects when you brush a mint plant. Isolate the pot and wash the leaves thoroughly.

Herbs Through the Darker Months

From November to February, growth slows and everything looks a little sorry. This is normal, not failure. Stop feeding, cut watering right back, and resist the urge to move plants somewhere warmer — a cool, bright windowsill is better than a warm, dim one. Turn pots a quarter-turn each week so stems grow straight rather than leaning towards the glass.

Trim dead leaves, remove any yellowing foliage, and be patient. By March the light returns, and with a little fresh compost on the surface and a gentle feed, your pots will be ready to crop again — a windowsill full of herbs, twelve months of the year.