Thyme is best cultivated in a hot sunny location with well drained soil. It is generally planted in the spring and thereafter grows as a perennial. It can be propagated by seed, cuttings, or by dividing rooted sections of the plant. It tolerates drought well.
Thyme retains its flavour on drying better than many other herbs.
Thyme is often used to flavour meats, soups and stews. It has a particular affinity to and is often used as a primary flavour with lamb, tomatoes and eggs.
Thyme, while flavourful, does not overpower and blends well with other herbs and spices. In French cuisine, along with bay and parsley it is a common component of the bouquet garni, and of herbes de Provence. In some Levantine countries, the condiment za'atar (Arabic for thyme) contains thyme as a vital ingredient.
Thyme is sold both fresh and dried. The fresh form is more flavourful but also less convenient; storage life is rarely more than a week. While summer-seasonal, fresh thyme is often available year-round.
Fresh thyme is commonly sold in bunches of sprigs. A sprig is a single stem snipped from the plant. It is composed of a woody stem with paired leaf or flower clusters ("leaves") spaced ½ to 1" apart. A recipe may measure thyme by the bunch (or fraction thereof), or by the sprig, or by the tablespoon or teaspoon. If the recipe does not specify fresh or dried, assume that it means fresh.
Depending on how it is used in a dish, the whole sprig may be used (e.g. in a bouquet garni), or the leaves removed and the stems discarded. Usually when a recipe specifies 'bunch' or 'sprig' it means the whole form; when it specifies spoons it means the leaves. It is perfectly acceptable to substitute dried for whole thyme.
Leaves may be removed from stems either by scraping with the back of a knife, or by pulling through the fingers or tines of a fork. Leaves are often chopped.
Thyme retains its flavour on drying better than many other herbs. Dried, and especially powdered thyme occupies less space than fresh, so less of it is required when substituted in a recipe. As a rule of thumb, use one third as much dried as fresh thyme - a little less if it is ground. Substitution is often more complicated than that because recipes can specify sprigs and sprigs can vary in yield of leaves. Assuming a 4" sprig (they are often somewhat longer), estimate that 6 sprigs will yield one tablespoon of leaves. The dried equivalent is 1:3, so substitute 1 teaspoon of dried or ¾ tsp of ground thyme for 6 small sprigs.
As with bay, thyme is slow to release its flavours so it is usually added early in the cooking process.
A tea made by infusing the herb in water can be used for cough and bronchitis. Medicinally thyme is used for respiratory infections in the form of a tincture, tisane, salve, syrup or by steam inhalation. Because it is antiseptic, thyme boiled in water and cooled is very effective against inflammation of the throat when gargled 3 times a day. The inflammation will normally disappear in 2 - 5 days. Other infections and wounds can be dripped with thyme that has been boiled in water and cooled.
In traditional Jamaican childbirth practice, thyme tea is given to the mother after delivery of the baby. Its oxytocin-like effect causes uterine contractions and more rapid delivery of the placenta but this was said by Sheila Kitzinger to cause an increased prevalence of retained placenta.
Thymus pseudolanuginosus (Woolly Thyme) is not a culinary herb, but is grown as a ground cover.
Thymus serpyllum (Wild Thyme) is an important nectar source plant for honeybees. All thyme species are nectar sources, but wild thyme covers large areas of droughty, rocky soils in southern Europe (Greece is especially famous for wild thyme honey) and North Africa, as well as in similar landscapes in the Berkshire Mountains and Catskill Mountains of the northeastern US.