How to Harvest & Dry Herbs for Winter: Air-Drying, Freezing & Storing

By the first week of September the herb bed is at its most generous and its most perishable. The oregano and marjoram are in flower, the mint has made its second flush, the basil is one cold night away from turning black, and every one of them will be a fraction of itself by the end of October. A morning spent cutting and hanging now gives you jars of thyme, sage, oregano and mint that outclass anything from a supermarket shelf, plus a freezer drawer of basil, chives and parsley for the herbs that refuse to dry. The rules are few, but they are not the ones most people follow: it is the leaf you want, not the stem; darkness and moving air matter more than heat; and the harvest starts before ten in the morning.

• Harvest Mid-morning, after the dew · just before flowering · annuals before the first frost, woody perennials by mid-September
• Dry Oregano, marjoram, thyme, sage, rosemary, savory, mint, lemon balm, bay · plus dill, fennel and coriander seed
• Freeze Basil, chives, parsley, coriander leaf, dill leaf, chervil, tarragon
• Store Whole leaves in airtight jars, dark cupboard · best within 12 months · 1 tsp dried ≈ 1 tbsp fresh

Why September, and why before ten o'clock

The flavour of a herb is its essential oil, and the oil is not a constant. In the plant's year it peaks in the leaf just as the flower buds form and falls away once it is in full bloom, which is why oregano cut in bud is worth twice the same plant cut a month later. In the day it is highest in the morning, once the dew has dried and before the sun warms the leaf enough to drive the volatile oils off — by early afternoon on a warm day a fair share of what you wanted is already in the air. Cut mid-morning, on a dry day, and you bank the difference.

September concentrates the calendar. The annuals — basil, dill, coriander, summer savory — are killed by the first frost, so this is their last harvest. The woody perennials — rosemary, sage, thyme — should take their last hard cut by the middle of the month, so that the regrowth hardens before winter; cut them hard in October and the soft shoots are frost-killed, sometimes taking the plant with them. Mint and lemon balm die back anyway, so cut whole stems to the ground now — the second flush of mint after a July cut is the best-flavoured of the year. And if the herbs you want are not in the bed at all, our guide to growing herbs from seed is where next year starts.

Dry the woody ones, freeze the soft ones

The single rule that saves the most disappointment: herbs with tough leaves, low water content and robust oils dry well; soft, juicy herbs do not. Oregano, marjoram, thyme, sage, rosemary, summer savory and bay all dry into something as good as, sometimes better than, fresh — the thymol and carvacrol that give thyme and oregano their punch survive drying and even concentrate. Mint and lemon balm dry well for tea, if a little less bright than fresh. Lavender and chamomile are cut in bud and dried whole.

The soft herbs are a different chemistry. The green, fresh notes of basil, chervil, coriander and tarragon are built from fragile compounds that leave with the water; dried, they taste of hay. Chives turn to grass, parsley keeps its colour and loses most of its flavour, and dill leaf fades while dill seed does not. All of these belong in the freezer, and all of them are exactly the herbs that crop fresh on a windowsill through winter if you sow them this month.

How to air-dry herbs, step by step

1. Cut mid-morning, just before flowering Whole stems of 15–20 cm with clean secateurs, once the dew has gone and before the heat. Never take more than a third of a perennial at once, and finish the hard cuts on rosemary, sage and thyme by mid-September.
2. Shake, do not wash Shake out the insects and leave the stems in the shade for an hour to wilt slightly. Wash only if they are genuinely muddy, then pat dry and wait until every leaf is surface-dry — water is what turns a bunch mouldy.
3. Tie small bunches Five to ten stems, no more, bound with a rubber band rather than string: stems shrink as they dry and slip out of string, while a band tightens with them. A fat bunch dries on the outside and rots in the middle.
4. Hang in the dark, warm and airy A spare room, a shed loft or an airing cupboard with the door ajar, at 20–30 °C with air moving. Not the kitchen, where steam keeps them damp, and never a sunny window, where light bleaches the leaves and destroys the oil. A paper bag with a few holes punched in it, tied round each bunch, keeps the dust off and catches any leaves that fall.
5. Test after a week Done when the leaves crumble between your fingers and the stems snap rather than bend: seven to ten days for thyme and oregano, two to three weeks for mint, sage and rosemary.
6. Strip whole, jar, label, check Strip the leaves whole into airtight glass jars — crumbling releases the oil you are trying to keep — label with the name and the date, and store in a dark cupboard away from the cooker. Look at the lid after a week: any condensation inside means the batch goes back on the rack.

Faster methods: oven, dehydrator and freezer

A microwave will dry a handful of sage or mint between two sheets of kitchen paper in thirty-second bursts, but it scorches without warning and is a last resort. For the soft herbs, the freezer is not a compromise but the right answer: chop them, pack them into ice-cube trays, top up with water or olive oil, freeze, then tip the cubes into a bag. Whole stems of parsley, coriander and dill freeze in a bag and crumble straight from frozen; chives are snipped and frozen loose; basil is best turned into pesto or frozen in oil, because it blackens the moment it thaws. The same drying principles, incidentally, apply to flowers — our guide to drying statice uses exactly the same dark, warm, airy rule.

Seeds and flowers: the other harvest

Dill, fennel and coriander give a second crop that dries far better than their leaves. Cut the seed heads when the seeds have turned from green to brown but before they drop — usually a week or two after the first ones fall — into a paper bag, hang the bag in the same dark room, and rub the seed out once it is loose, then give it another week on a plate. Kept dry, the same jar is both your spice rack and next spring's seed packet; our seed saving guide covers which will come true, and how long seeds last tells you how many years you can rely on it. Chamomile and lavender flowers dry on a tray in a single layer, mint flowers make a better tea than the leaves, and a bunch of catnip dried the same way will keep a cat entertained until spring.

Common herb-drying mistakes

• Cutting after flowering — the oil has already dropped. Flavour is thin and the leaf is often bitter.
• Washing, then hanging wet — water means mould. Shake, wilt, or dry thoroughly before you bundle.
• Bunches the size of a fist — the outside dries, the middle rots. Five to ten stems.
• Drying in the sun or the kitchen — light bleaches the leaves and heat drives off the oil; steam keeps them damp.
• Crumbling before storing — the oil lives in the whole leaf. Crumble in the pan, not into the jar.
• Jarring too soon — one slightly damp batch moulds a whole jar. Test for snap, and check the lid a week later.
• Cutting rosemary or sage hard in October — the soft regrowth is frost-killed, and the plant can follow it.
• Keeping jars for years — dried herbs are at their best inside twelve months. If a jar smells of nothing, it tastes of nothing.

Frequently asked questions

How long do dried herbs keep?
At their best for six to twelve months, and usable for up to two years, provided they are stored as whole leaves in an airtight jar in a dark, cool cupboard. Heat, light and air are the enemies, which is why the rack above the cooker is the worst place in the house for a spice collection. The test is simple: rub a pinch between your fingers and smell it. If nothing happens, it has gone.

Can I dry basil?
You can, and you will be disappointed. Basil's flavour compounds are among the most fragile of any herb, and air-dried basil tastes of very little. If you must, a dehydrator at 35 °C is the gentlest route. Better to freeze it — as pesto, or chopped in olive oil in ice-cube trays — and to sow a fresh pot next spring; there are thirty-odd varieties in the basil collection.

Should I wash herbs before drying them?
Preferably not. From an unsprayed garden a good shake is enough, and every drop of water you add is a drop that has to leave again before the herb is safe to jar. If the stems are muddy, rinse them, pat them dry and lay them out for a few hours until every leaf is surface-dry before you tie a bunch.

How much dried herb equals fresh?
Roughly a third: one teaspoon of dried for one tablespoon of fresh. Dried herbs need time and moisture to release their flavour, so they go in early in a stew or a sauce, while fresh herbs go in at the end. The exception is anything from the freezer, which behaves like fresh.

Two hours with secateurs and a handful of rubber bands this week fills the winter cupboard, and the herb bed is better for the cut. While you have the tools out, the other September job is in the vegetable beds: if you grew radicchio or sugarloaf this year, our new guide to growing chicory from seed explains why the cold weeks ahead are the ones that make them worth eating, and any tender herbs in pots — a bay tree, a lemon verbena, a scented pelargonium — come indoors along with the rest of the tender plants before the first frost. Browse the herb seed collection, the culinary herbs and the organic herbs, check what else can still go in via the seeds to sow this month and the herb sowing calendar, and keep the rest of our growing guides to hand for everything that comes next.