Growing and pruning thyme: keep it lean, cut it right

Thyme is one of the most rewarding herbs there is, once you understand one thing: it comes from the Mediterranean maquis, from stony slopes where no rain falls for weeks in summer. Everything you do in the garden should imitate that origin. Give it sun, poor soil and little water, and a single small plant will carry you through the kitchen for years. Overdo the care, and it thanks you with rot.

The right spot: lean, sunny, dry

Look for the hottest, driest corner you have. A south-facing wall, the edge of a dry-stone wall, the joint between two paving slabs, a pot on a sunny balcony. Thyme needs at least six hours of direct sun, more is better. In shade it grows long, soft and low on aroma.

The soil matters more than anything else. Ideal is a free-draining, rather stony substrate that lets water seep away fast. Improve heavy, loamy garden soil before planting with a good helping of coarse sand or fine grit. A pH of 7 to 8 is perfect, thyme likes it chalky. Waterlogging is its one real enemy, and wet winter soil kills more plants than any frost.

Planting: buying, sowing and the right spacing

The easiest start is a bought young plant from the herb pot, from April into early summer. Look for compact, firm growth rather than long, pale shoots, that tells you it was raised well. Set it as deep as it sat in the pot, firm the soil and water in once thoroughly. After that, deliberately hold back on watering.

Sowing works too, but takes patience. Thyme is a light germinator: from CW 12, scatter the fine seed onto the surface and press it down without covering it. At 18 to 20 degrees it germinates in two to three weeks, often unevenly. For a single kitchen herb a bought plant is worth it, for a larger bed or a thyme edging, sowing is the cheap route.

Keep 25 to 30 cm between plants. That sounds like a lot for the small seedlings, but a healthy bush grows wide, and air between the plants prevents fungus.

The cut decides how long it lives

This is where the thyme that lasts ten years parts ways with the one that becomes a grey, bald skeleton after three. The secret is a regular but cautious cut back. Thyme goes woody from the bottom up, and it re-sprouts only reluctantly from old, brown wood. Cut too deep and you are left with bare stems that stay bald.

The main date is early spring, as soon as no hard frost threatens, roughly CW 12 to 16. Then shorten the plant by about a third, down to just above green growth. A second, light trim after flowering in high summer keeps the bush compact and drives fresh, aromatic leaf for autumn.

1. Pick the moment

   Wait for the first mild weather in spring, CW 12 to 16, when nights no longer drop well below zero. A dry day is ideal, so the cut surfaces dry off quickly.

2. Remove the dead and tangled

   First take out withered, broken and inward-growing shoots entirely. That brings light and air into the bush.

3. Shorten by a third

   Cut the healthy shoots back by about a third, always to just above a green spot. Keep the plant rounded, a half-dome shades itself and stays dense.

4. Tidy up after flowering

   Once the bloom in July or August is over, trim the spent flower heads lightly. That prevents ageing and gives you tender new leaf into autumn.

Harvesting: all year, best before flowering

Thyme is evergreen, so you can cut a few sprigs for the Sunday roast even in winter. The strongest aroma, though, is in the shoots just before flowering, usually in June. The essential oils peak then. Cut best on a dry morning, once the dew has gone and the sun has not yet driven the oils out of the leaves.

Take whole shoot tips of 5 to 10 cm, not single leaves. That is faster and works like a harvest cut that keeps the plant bushy. To dry, tie the shoots loosely and hang them upside down in an airy, shady place. Dried thyme keeps its aroma remarkably well, unlike most other herbs.

Overwintering and renewing

Common thyme is hardy here and survives frosts down to about minus 15 degrees. The danger is less the cold than the wet: a wet, compacted winter soil kills more plants than any frost. In harsh spots and during bare frost without snow, lay some brushwood or fir branches over the mats. In a pot it is more frost-prone, because the root ball freezes through. Move it close to the house wall and wrap the container in fleece.

After four to five years most bushes go bald from the inside, no matter how well you prune. That is normal. Instead of fighting it, raise replacements in good time. The easiest way is layering: in early summer lay a low shoot on the soil, weigh it down with a stone, and after a few weeks it has its own roots. Then you separate it and have a young plant. Cuttings from non-flowering shoot tips also root willingly in lean, sandy substrate.

Varieties for kitchen and bed

Beyond the classic common thyme, a few relatives are worth a look, each taking on a different job in the garden.

Whichever you choose, the recipe stays the same: sun, poor soil, little water and an honest cut in spring. Best of all, enter the spring prune as a recurring task in your garden journal, then you never forget it and your thyme lasts twice as long.

Common questions about thyme

Why does my thyme go bald and woody from the inside?

That is the nature of thyme: it goes woody from the base over the years. Cutting too deep, or not at all, speeds it up. Prune back by a third every spring, but never into the brown wood. Once the bush is spent after four to five years, raise a young plant through layering.

How often do I need to water thyme?

Very rarely. Established thyme in the bed manages almost without extra water and suffers more from too much than too little. Only water fresh plantings and pots, and even then only once the soil has really dried out.

Can I keep thyme in a pot on the balcony?

Yes, that works well as long as the spot is full sun. Use a clay pot with a hole, mix the soil with plenty of sand and never let water stand in the saucer. In winter move the pot to the house wall and give it a fleece jacket.

When does thyme taste best?

It is strongest just before flowering in June, cut on a dry morning. But you can harvest it all year, even in winter, because it is evergreen.

Is thyme hardy?

Common thyme survives frosts down to about minus 15 degrees here. The bigger risk is wet winter soil. Provide drainage, and protect the mats with some brushwood in harsh spots during bare frost.