Thyme Growing Calendar: What to Do in Each Season

The year at a glance

Thyme is an evergreen perennial, so there is no sowing and planting rush and no clearing up at the end. The work is concentrated into two pruning cuts and one autumn tidy, and a plant that gets those three things will stay dense and productive for years.

Spring: plant, clip and start cuttings

Once the soil has warmed and hard frosts have passed, this is the time to put new plants in. Thyme establishes fast in warm, well-drained soil and a spring-planted plant is fully settled before its first winter, which matters far more than getting an early start.

On established plants, wait until you can see new growth before cutting anything. Winter-blackened tips look dead in late winter and often push new shoots from just below, so cutting too early takes away growth you would have kept. Once growth is visibly moving, shorten every shoot by an inch or two.

1. Plant 12 inches apart, crown proud Space plants a foot (30 cm) apart and set the crown an inch above the surrounding soil. Water in, then leave them to it apart from a weekly watering for the first month.
2. Sow seed under cover if you are sowing Sow on the surface of gritty potting mix, barely covered, at 65 to 70F (18 to 21C). Expect two to four weeks and uneven germination.
3. Give the light spring clip Shorten each shoot by one to two inches (3 to 5 cm), staying in green growth, and take out any blackened winter tips at the same time.
4. Take cuttings and pin down layers Late spring softwood cuttings root fastest. Pin a couple of outer shoots down at the same time and you have replacements coming without any extra work.

A single light dressing of a low-nitrogen fertilizer now is all the feeding thyme needs for the year, and in decent open ground you can skip even that.

Summer: harvest, then the cut that matters

The big harvest for drying comes when the flower buds are formed but not yet open, when the oil content is at its highest. Cut generously then, but stay within a third of the plant. After that, let it flower: the flowers are edible, they are excellent for bees, and the plant loses nothing by them.

As soon as flowering finishes, cut the whole plant back by about a third, staying in leafy growth and leaving at least two pairs of leaves on every stem. This is the single most important job of the thyme year and the one most often skipped. Done every year, the plant stays dense; skipped for two years, the middle is bare wood and cannot be recovered.

1. Cut the drying batch pre-flowering Take four to six inch (10 to 15 cm) sprigs in the morning once the dew has gone, and hang them to dry the same day.
2. Let it flower for the bees Thyme in flower is one of the best things you can offer pollinators. There is no reason to remove the flowers on a plant you are also cutting back afterwards.
3. Cut back by a third after flowering Immediately after the flowers fade, take the plant back by a third all over. Use the material: it is a large, good-quality harvest.
4. Water containers, ignore the border Pots dry out fast in summer heat and need watering when dry an inch down. Established plants in the ground need nothing except in a long drought.

Semi-ripe cuttings taken from the post-flowering material root well. Since you are cutting the plant anyway, stick a dozen and you have next year's replacements for nothing.

Autumn and winter: keep it dry and leave it alone

Stop cutting about six weeks before your first expected frost. Late cuts push soft shoots that never harden, and those are the ones that blacken and rot. From then on the work is about water, not about the plant: clear fallen leaves and dead litter from around the crown, pull organic mulch back and replace it with grit, and lift pots onto feet so they drain.

Through winter, do almost nothing. No feeding, no cutting, and watering only if a container has gone bone dry. Thyme in a dry soil shrugs off severe cold; the plants that die are the ones sitting wet. Resist tidying up frost-blackened tips until growth restarts in spring, because you cannot yet tell what is dead.

Write down which plants came through and which were lost, and where each one was standing. After two winters that note tells you exactly which parts of the garden are too wet for thyme, and no general advice can tell you that.