Harvesting, drying and storing garden plants

A fresh leaf holds a lot of water. As long as that water is there, mould can set in and the plant loses its scent. Drying means removing that water quickly enough. Here's when to harvest, how to dry and how to store your plants.

When to harvest

• In dry weather, between 9 and 11 a.m. The dew is gone and it's not too hot yet. Touch the leaves: they should be dry. A wet plant dries poorly and moulds more easily. Later in the day, the heat makes it lose its scent.
• After rain, wait a day or two.
• Don't wash leaves or flowers: water encourages mould. Only roots get washed.
• Use a basket, not a bag, without packing it down, and set everything to dry within the hour: a pile of fresh plants heats up quickly.

How much to harvest, and until when

Never take more than a third of a plant at a time.

On perennials (thyme, sage, lavender, oregano, lemon balm, winter savory), stop harvesting around mid-August. After that, new growth doesn't have time to harden before the first frosts, in late September or early October. The plant goes into winter weakened and may not come back in spring.

Annuals (basil, dill, cilantro, German chamomile) can be harvested until the first frost.

Which part to harvest, and when

• Leaves: before flowering. Once flowers start forming, the leaf loses its aroma. For mint and lemon balm, harvest just before the flower spikes appear.
• Flowering stems, on non-woody plants (yarrow, goldenrod, agastache): cut the top 15 to 20 cm of the stem as soon as the first flowers open.
• Flowering stems, on plants with woody stems (lavender, thyme, sage, hyssop, winter savory): cut 5 to 10 cm into this year's green growth, never into the old bare wood, which doesn't grow back.
• Flowers: the day they open. Left too long on the plant, they turn brown as they dry.
• Roots: once the leaves have yellowed and before the ground freezes, from late September to late October. For burdock, angelica and evening primrose, harvest in the fall of the first year, while the plant is still just a tuft of leaves at ground level. For echinacea, elecampane, marshmallow and comfrey, wait three or four years. Wash, scrub and slice the roots thinly right away: once dry, they're as hard as wood.

How to dry

Flat, in a single layer, on something that lets air through from below: a stainless steel rack, a wicker tray or a wooden frame covered with cotton. Don't use an old window screen: it isn't made for contact with food. This method suits petals, flowers, loose leaves and root slices. The leaves shouldn't touch, or moisture gets trapped between them.

In small bunches, hung upside down, for plants with thin stems: thyme, savory, oregano, yarrow, lavender, goldenrod.

• No more than about ten stems per bunch (five or six for mint and lemon balm).
• Tie them with an elastic band rather than string: stems shrink as they dry and the elastic follows.
• Leave a hand's width between bunches.

Careful: a bunch that's too tight moulds in the middle, with nothing showing on the outside. You find out too late, and the whole bunch has to go.

Basil, chives, parsley, cilantro and tarragon hold too much water to air-dry: they turn black or mouldy. Freeze them, or dry them in a dehydrator at 35 °C. Harvest basil before the first nights below 10 °C: a single cold night is enough to spot it with black.

Where to dry

You need a dry, dark, airy spot, at 35 °C at most.

• Dry: above 60% humidity in the air, plants stop drying. Humid August days often go above 80%. A hygrometer will tell you. If the air is too humid, close the room and run a dehumidifier, or finish in a dehydrator at 35 °C.
• Dark: light fades plants and makes them lose their scent.
• Not too hot: above about 35 °C, leaves and flowers lose their fragrant oils, and the outside dries while the inside stays damp. They look dry but mould in the jar. Roots and bark, on the other hand, dry better at 40 to 45 °C in a dehydrator.

The best spot is a closed room upstairs, like a guest room or a little-used office. Avoid the kitchen and bathroom (steam), the attic and metal sheds (too hot in summer), as well as barns or any unheated building (damp at night, mice, hay dust).

Count from three days for rose petals to two weeks for a thick stem like agastache. If a leaf or flower is still soft after seven to ten days, it won't dry anymore: it's going to mould.

How to tell it's dry

A properly dry stem snaps cleanly. If it bends, there's still water in it. Always test the thickest part: the leaves can be dry while the stem is still damp, and that's what will make the jar mould.

How to store

• Keep leaves whole and crumble them only when you use them: they keep their scent better.
• Store them in a glass jar with an airtight lid in a closed cupboard, or in an opaque container: light damages them even through glass.
• Write the plant's name and the date on the jar when you fill it. Once dried, many plants look alike (lemon balm and mint, oregano and marjoram).
• For the first week, check the jar every day. If there's condensation, there was still water: take everything out and dry it again.

Leaves and flowers keep for about a year, after which they lose their scent. Well-dried roots, bark and seeds keep for two to three years. If you notice a musty smell, a spot or unusual dust at the bottom of the jar, throw it all out.

Safety: only harvest what you know

Identify the plant with certainty, down to the exact species. Be extremely careful with plants in the carrot family (wild carrot, angelica, hogweed):

• poison hemlock looks like them, grows in ditches and damp meadows in Quebec, and can kill within hours;
• giant hogweed and cow parsnip cause serious burns if their sap touches skin in sunlight.

Never harvest one of these wild plants unless someone who knows them well has identified it, and never from a photo. When in doubt, don't harvest.

Only harvest untreated plants:

• not from a bed treated with a pesticide in the last two or three years: some products stay in the soil and get taken up by the plant;
• not along roadsides, because of dust and road salt;
• not from a plant bought as an ornamental, even from us: the rules aren't the same for a plant sold for its flowers and a plant meant for tea. Before harvesting a plant bought from us, ask us how it was grown.

Our plants are offered for traditional use. We don't claim any medicinal properties and don't promise any effect. If you have a health condition, are pregnant or take medication, talk to your pharmacist.

In short

• Harvest in dry weather, between 9 and 11 a.m., never more than a third of the plant. No more harvesting perennials after mid-August.
• Flat, in one layer, for flowers, leaves and sliced roots. In small, loose bunches for thin stems. Basil, parsley and chives go in the freezer or a dehydrator.
• A dry, dark, airy spot, no warmer than 35 °C. Above 60% humidity, you need a dehumidifier or a dehydrator.
• It's dry when the stem snaps cleanly. Closed, labelled jar; condensation means it wasn't dry enough.
• Never harvest a wild plant from the carrot family without certain identification: poison hemlock is deadly.