Thyme in September: monthly care

Thyme thrives in full sun and well-drained soil, making it ideal for sunny borders, rockeries, gravel gardens, or containers. It tolerates sandy, chalky, and loam soils but abhors waterlogging, so excellent drainage is essential. If your soil is heavy clay, work in plenty of grit or sharp sand before planting, or grow thyme in raised beds or pots filled with a gritty, free-draining compost. Plant thyme in April, May, or September when the soil is workable and temperatures are mild. Space plants 25 cm apart to allow for their spreading habit, which typically reaches 20–40 cm across. Dig a hole slightly larger than the root ball, set the plant at the same depth it was growing in its pot, and firm the soil gently around the roots. Water in lightly after planting, but avoid saturating the soil. If planting from seed, sow thinly on the surface of moist, gritty compost in spring, as thyme seeds need light to germinate. Keep at around 15–20°C and transplant seedlings once large enough to handle, hardening them off before planting out after the last frosts. After planting, water sparingly until the plant is established—thyme is drought-tolerant once its roots have settled in. A thin layer of gravel or grit mulch around the base helps suppress weeds, improves drainage, and reflects heat, which thyme appreciates. Avoid organic mulches like compost or bark, which retain moisture and can encourage rot. Thyme is hardy to zone 5a and evergreen in our climate, so it will provide year-round interest and foliage for picking.

Thyme is a low-maintenance herb once established, requiring minimal intervention. Its water needs are low; in fact, overwatering is the most common cause of failure. Water sparingly during prolonged dry spells in the first growing season, but once the roots are established, thyme tolerates drought well and rarely needs watering except in containers. In pots, allow the compost to dry out between waterings and ensure excellent drainage to prevent root rot. Feeding is not necessary. Thyme naturally grows in poor, stony soils in the Mediterranean and actually produces more flavourful, aromatic foliage when grown lean. Avoid fertilisers, which encourage soft, sappy growth prone to winter damage and reduce the concentration of essential oils that give thyme its flavour and scent. Thyme is evergreen and fully hardy in zones 5a–9b, so it requires no special protection over winter in our climate. However, it dislikes sitting in cold, wet soil during winter, so ensure drainage remains good. A gravel mulch helps. In very exposed sites or heavy clay, consider growing thyme in containers that can be moved to a sheltered spot if necessary. Pests are rarely a problem, though thyme can occasionally suffer from root rot (Phytophthora) in waterlogged conditions—prevent this with good drainage. Aphids may appear on soft new growth in spring; wash them off with water or tolerate them, as they seldom cause lasting harm. Harvest leaves and sprigs freely from May to September. Thyme's flavour is strongest just before flowering in early summer, but you can pick year-round as needed, as it remains evergreen.