Herb production: Growing hardy thyme


By Digital team | 1 November 2017
Photo: Berna Coetzee

Thyme is the hardiest of all the herbs and can by cultivated successfully throughout the year.

Thyme (Thymus vulgaris) is a low-growing perennial herb that rarely grows more than 40 cm tall. If nurtured, it grows into a small, bushy plant and the more often the leaves are picked the better it performs.

Garden thyme is the most common type used and sold commercially in the fresh and dried markets. The South African Department of Agriculture, Forestry and Fisheries’ (DAFF) guidelines on cultivating thyme explain that the leaves are very small, usually 2.5 mm to 5 mm in length, and that they vary in shape and hairiness, depending on the cultivar.

The fragrance of the leaves is the result of an essential oil, which is the source of thyme’s medicinal properties and gives the plant its flavouring value for culinary purposes.

Thyme grows well in temperate to warm, dry and sunny climates. It needs full sun to grow to its full potential and doesn’t like excessive watering because of its susceptibility to rotting diseases. When choosing an area to plant, make sure the soil is well drained, with a pH of 5,0 to 8,0.

If you have an area that’s unsuitable for many other plants, you could plant thyme there as the species performs best in coarse, rough soils. Thyme can be planted successfully in soil that’s very shallow and where other crops cannot survive. The DAFF guidelines point out that thyme cultivated in heavy wet soils will be less aromatic.

PROPAGATION

Thyme is usually propagated from seeds, stem cuttings, and layering from an established clump, or by dividing the plants and replanting the rooted sections.

If propagating by seed, sow seeds in spring at a depth of 6 mm or less. Seeds should germinate in about two weeks, but if planted in seed trays they will take six to eight weeks to reach transplant readiness.

The DAFF guidelines advise that growers transplant the seedlings outdoors after the danger of frost during winter has passed. If the plants are established and growing well before winter, the small plants can withstand frost.

Although thyme is a perennial, the stems can become woody as the plant ages. Cassie Snyman, manager of a Pretoria-based herb nursery, points out that it might be necessary to replace the plant after three to four years. But don’t be scared to prune the bush vigorously to encourage new growth.

PLANT MAINTENANCE

Snyman says it isn’t necessary to fertilise thyme in the winter months. The plants aren’t growing fast and don’t require much feeding. Rather wait until plants emerge from their dormant phase in the warmer months before fertilising.

Generally, thyme should not be fertilised heavily because over-fertilised plants tend to show tall, spindly, and weak growth. The DAFF handbook advises that a basal fertiliser application containing nitrogen, phosphorus, potassium and sulphur be applied annually, according to soil analysis results.

Thyme responds well to additional applications of nitrogen, usually administered after each harvest, to promote new shoot growth during the growing season.

CULTIVARS

Genus Thymus has about 215 species and numerous hybrids, but the three main varieties are the broad-leaved, narrow-leaved and variegated thyme. Narrow-leaved thyme has small, grey-green leaves and is more aromatic than the broad-leaved one.

Fragrant lemon thyme has a lemon flavour and broader leaves than ordinary garden thyme. The silver thyme is the hardiest of all and has the strongest flavour.

DID YOU KNOW?

Thyme is recommended for rock gardens or as border plants in herb gardens.

Thyme’s roots have a tendency to “heave” after planting and become sun-scorched. Make sure they are covered with soil after transplanting.

Also read: Herb production: How to grow peppermint

  • This article was written by Wilma den Hartigh and first appeared in Farming SA.