How to grow thyme

Common thyme is easy to raise from seed, and a packet gives you far more plants than a pot from the garden centre. Many of the named varieties, such as lemon, caraway and most coloured-leaf forms, are sold only as plants and are propagated from cuttings.

Sow indoors from February to April. Seedlings grow slowly at first, so an early start pays off if you want a plant big enough to pick from in the first summer. Direct sowing outdoors is possible from mid-April to mid-May, but the tiny seedlings are easily lost among weeds.

Plant young thyme out from mid-spring to early summer, roughly April to June, once the worst of the cold, wet weather is over. Plants set out by early summer have time to root in before winter.

Scatter the fine seed thinly on moist seed compost and press it in without covering it: thyme needs light to germinate. At 59–68°F it comes up in about two weeks, often unevenly. Prick the seedlings out in small clumps once they are big enough to handle.

Thyme wants full sun and light, free-draining soil. Neutral to chalky ground suits it, anywhere from about pH 6 to 8, and a little lime does no harm. On heavy clay, work in plenty of grit or sand, or grow it in a raised bed or a pot of soil-based compost mixed with up to a quarter grit.

Space plants 8–12 in apart. In a 120 × 80 cm raised bed at 10 in that would be a dozen plants, but two or three are plenty for a kitchen. Give them the sunniest, driest edge of the bed, where they can spill over the side, and leave the richer middle to vegetables. A pot should be at least 6 in wide.

Once established, thyme is drought-tolerant and rarely needs watering in the ground; water new plants until they have rooted, and pots in hot spells. It doesn't need feeding either. Rich soil and frequent watering make it soft, short-lived and less aromatic.

Trim it lightly to keep it compact: in spring as growth starts and again after flowering. Cut into the leafy part of the stems rather than hard back into bare wood. Do the last trim by early September so the new shoots can firm up before winter.

Common thyme is hardy in Central European and UK winters; growers have seen it come through 5°F without damage. What kills it is wet: heavy, waterlogged soil or a pot standing in water. Raise pots on feet over winter and give tender varieties some brushwood cover in cold areas.

After a few years, thyme plants turn woody and straggly in the middle. Replace them then with new plants from softwood cuttings, layering or division.

You can pick thyme all year, but the soft new growth of late spring and summer has the best flavour. Snip non-woody sprigs as you need them, and leave plenty of leafy growth on the plant.

Thyme is one of the few herbs that dries well and keeps its strong flavour. Cut sprigs on a dry morning, just before the plant flowers, hang small bunches somewhere airy and shaded, then strip the leaves and store them in a jar. The flowers are edible too, and bees love them.

Common or garden thyme (Thymus vulgaris) is the upright, grey-green kitchen classic, usually 4–16 in tall. Lemon thyme (Thymus × citriodorus) smells of lemon and comes in golden and variegated forms. Caraway thyme (Thymus herba-barona) is low and spreading with a caraway scent.

Creeping or wild thyme (Thymus serpyllum) forms flat mats that suit paving cracks and the edges of raised beds. It is edible but milder than common thyme.

Thyme has few serious pests. Slugs go for young shoots, and rosemary beetles and leafhoppers nibble the leaves, rarely badly. The most common cause of death is root rot in soil that stays wet, especially over winter.

Thyme belongs to the mint family, Lamiaceae, with basil, sage, oregano and rosemary. As a perennial it sits outside the vegetable rotation: give it a permanent sunny spot, such as a herb corner or the edge of a raised bed, and move it only when you replace old plants.

Planting tables often put thyme next to cabbages to deter cabbage whites, or among roses and strawberries. We found no solid evidence for these pairings; they are tradition.

What does matter is that neighbours want the same conditions. Thyme does best alongside other Mediterranean herbs such as sage, oregano, rosemary and lavender, on lean, dry soil. Next to thirsty, heavily fed vegetables it gets watered and fed too much.