This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Three sorts are cultivated, common narrow-leaved, common broad-leaved, and Lemon Thyme. The two first are used for the same purposes - for seasoning stuffings principally - and it is therefore not needful to grow both. Lemon Thyme is not used so much as the other, but it is preferred for some purposes. The common Thyme is a native of the south of Europe, is an evergreen, and perfectly hardy. It requires a light rich soil, and may be propagated by seed, or by dividing the plants in spring. By seed is the best way to insure vigorous free-growing plants, when it is found necessary to raise a new stock, which is not often, as the same plantation will last for some years. For expedition, the seed should be sown in pans, in March, covered very slightly with fine soil, and forwarded in a gentle heat. When the plants can be handled conveniently they should be hardened off gradually, and afterwards planted out in rows, 7 or 8 inches apart, and about 4 or 5 inches from plant to plant, and watered occasionally till they are established. In favourable situations the seed may be sown at once in the bed in shallow drills, and the seedlings afterwards thinned out to the above distances apart.
When propagated by division, the plants should be taken up about the beginning of April and split up into pieces, and the youngest and best-rooted branches should be selected for planting a fresh bed. The ground should be deeply dug, and otherwise well prepared, and the plants should be watered frequently in dry weather. To insure good roots, the branches are sometimes layered some time before planting, but we never found this needful. Lemon Thyme is propagated in the same way as the other. When coming into flower, a portion should be cut and dried for winter use.