James Hartley
Why a windowsill suits herbs so well
Most of the herbs we reach for in the kitchen come from sun-baked, free-draining hillsides. They are not fussy about depth of soil or the size of a garden — they simply want good light, decent drainage and a bit of warmth. A windowsill delivers all three, and it puts the crop within arm's reach of the chopping board, which is half the reason to grow herbs at all.
A south-facing sill is the prize spot and will suit basil, thyme and rosemary. East and west windows are gentler but still bright enough for most culinary herbs. North-facing windows are dimmer, so save those for mint, chives and parsley, which cope with a little shade. Bear in mind that a sill is a peculiar microclimate: temperatures behind glass can climb sharply on a bright July afternoon and drop steeply on a frosty night in January. Plants sit close to radiators in winter and beside draughty sash windows. Work with that, and a modest sill can crop for most of the year.
Choose compact varieties that earn their space
Space is tight, so pick plants bred to stay neat rather than sprawling. Bush or dwarf forms are far easier to manage than vigorous garden varieties.
- Basil — look for compact bush types rather than the tall, floppy ones. Small-leaved varieties keep their shape and re-grow quickly after picking.
- Chives — naturally clump-forming and perfectly happy in a small pot. Snip the leaves and they will push up fresh ones within a fortnight.
- Mint — wonderfully vigorous, which is also the problem. Always give it its own pot, because it will run through anything it shares with. Spearmint and Moroccan mint are both well behaved in a container.
- Thyme — creeping and compact forms stay low and tidy, and they positively prefer being kept on the dry side.
- Parsley — a flat-leaf or curled type with a tight habit will give you a long, steady supply of leaves from a single pot.
Three or four pots is plenty to begin with. A small, well-tended collection beats a crowded sill where nothing gets enough light.
Pots, compost and drainage
Choose pots at least 12–15cm across for individual plants, or a shallow trough for a group of chives or thyme. Terracotta looks lovely and dries out faster; glazed or plastic pots hold moisture for longer, which suits mint and parsley. Whatever you use, drainage holes are non-negotiable, and a saucer underneath protects the paintwork. Empty the saucer an hour after watering so roots are never left standing in water.
Use a peat-free multipurpose compost, and stir through a handful of grit or perlite to open it up. Herbs loathe compacted, soggy roots, and the extra air improves drainage no end. Fill pots to about 2cm below the rim so there is room to water without it sloshing over the edge.
Watering: little and often, but check first
Small pots dry out quickly, especially in a warm room, so expect to check them daily in summer. Rather than sticking to a rigid schedule, test the compost with a finger pushed in to the first knuckle. If it feels dry at that depth, water; if it is still damp, wait. Lifting the pot is another useful trick — a light pot needs water, a heavy one does not.
Water in the morning where you can, using a small can with a fine rose so you do not wash the compost away from the stems. Aim for the compost, not the foliage. Group plants with similar thirst together: mint and parsley like to stay reliably moist, while thyme and rosemary prefer to dry out between waterings. Overwatering is the single most common way to lose a windowsill herb, and yellowing lower leaves are usually the first sign.
Turn your pots so every stem gets its share of light
Plants lean towards the window. Leave a pot in the same spot for a week and you will end up with a lopsided specimen, bare on one side and stretched on the other. Give each pot a quarter turn every day or two, and the growth will stay even and upright. It takes seconds and makes a real difference to the shape of the plant.
In winter, light levels fall away sharply, so move pots to the brightest sill you have and ease back on watering. If stems still become thin and leggy, the plant is reaching for light — a small, inexpensive clip-on grow light can carry basil and parsley through the darkest weeks, though mint and chives will usually manage without.
Harvesting, feeding and keeping things going
Regular picking keeps herbs bushy rather than tall and woody. Pinch out basil tips just above a pair of leaves to encourage side shoots, and never strip more than a third of the plant at once. Snip chives about 2–3cm from the base and they will regrow quickly; cut mint stems freely, as it responds well to a firm hand.
Feed every two to three weeks through spring and summer with a diluted liquid feed — tomato feed or a seaweed tonic both work well. In winter, stop feeding altogether and let the plants rest. Watch for greenfly clustering on soft new tips; a firm squirt of water usually dislodges them. If tiny flies hover around the pots, you are probably overwatering, so let the surface dry out between drinks.
After a few months, plants that have cropped hard will begin to tire. Rather than coaxing them along, sow or buy fresh ones and start the cycle again. Rotating a new pot in as an old one fades keeps the sill productive all year — and there is something quietly satisfying about snipping your own basil in the middle of a grey British February.
