At a glance
- The harvest hour matters: pick on a dry morning once the dew has lifted and the essential oils sit high in the herb.
- Leaves just before flowering, blossoms freshly opened, roots in autumn. Every plant part has its own window from CW 22 to 32.
- Dry in the dark, airy and always below 40 degrees. Higher heat drives out exactly the aromatic compounds you grew the herb for.
- A leaf is fully dry when the stem snaps instead of bending. Depending on the herb this takes 3 to 14 days.
- Stored airtight, dark and labelled, your herbal tea stays fresh for a year, right up to the next harvest.
There is that one moment in summer when the peppermint in the bed grows so thick you can barely keep it in check. That is exactly when the scissors pay off. A bunch of mint, a few chamomile flowers, a handful of lemon balm, brewed in winter, and the whole of July is back in your cup. Home-dried herbal tea is no magic trick, but it hinges on two levers: the right harvest time and drying below 40 degrees. Master those two and you turn the garden surplus into a stock that lasts until next spring.
Why the harvest hour decides the flavour
Essential oils are volatile. They shift within the plant along the daily rhythm, and their content varies noticeably over the course of a day. In the early morning, while dew still sits on the leaves, the herb is full of water and the oils are low. In the blazing midday sun, part of the aromatics already evaporates from the living plant. The best window is in between: on a dry, sunny morning once the dew has dried off, usually between 9 and 11 o'clock.
Wait for a few dry days if you can. Herbs harvested right after a downpour bring moisture that lengthens the drying and invites mould. And never cut wet foliage. Every drop of water that sits on a leaf too long while drying is an invitation for rot.
A simple rule of thumb for harvest day: if you walk barefoot across the lawn in the morning and your feet stay dry, the herb is ready to pick. If the grass feels clammy, wait another hour.
Every plant part has its own window
Not everything is harvested at the same time. The active-compound content depends on the developmental stage, and that differs completely between leaf, blossom and root.
- Leaves: just before flowering
In mint, lemon balm, sage and thyme the essential oils are densest just before the first flower buds open. After that the plant pours its energy into blooming and the leaves grow paler. The window usually falls between CW 22 and 26.
- Blossoms: freshly opened
Chamomile, calendula and linden blossom are picked once the flower is fully open but not yet past its prime. In chamomile the ray florets are still horizontal at that point, not folded downward. Peak season is CW 24 to 30.
- Seeds and fruits: at full ripeness
Let fennel, caraway and coriander ripen until the umbels turn brown and the seeds drop easily. That is often not until CW 30 to 34.
- Roots: in autumn
Dig up valerian or comfrey only after the first frost, once the plant has pulled its strength back down. That falls outside the summer window but belongs here for completeness.
For the classic summer herbal tea from the bed you mostly deal with leaves and blossoms. And there it pays to look at the two queens more closely.
Peppermint (Mentha × piperita) is the most reliable starter plant for your own tea. Cut the whole shoot a hand's width above the ground, just before the first flowers open. The plant regrows willingly afterwards, so you often get two harvests a year. A single bunch of mint is enough to fill a whole storage jar. The one thing that matters is not to wash it, only shake it out.
German chamomile (Matricaria chamomilla) asks for a little more patience. You pick only the flower heads, ideally with a chamomile comb or simply stripped between two fingers. Fully open, but not past its prime, is the right state. Because each flower ripens on its own schedule, you walk the bed several times over the weeks. It sounds tedious, but it is one of the loveliest quiet garden jobs of high summer.
The 40-degree rule when drying
This is the point where most home-made teas lose their flavour. Essential oils escape as the temperature rises. Above 40 degrees you drive out exactly the compounds you grew the herb for. The dried tea then still looks green but smells of nothing. So the rule is: slow and cool beats fast and hot.
Air, darkness and patience are the three ingredients. Air carries the moisture away, darkness protects colour and active compounds from fading, and patience gives the plant the time to dry through evenly. A draughty attic, a pantry or a shady shed are ideal. Direct sun is the most common mistake: it bleaches the herb and heats it above the critical mark.
Green it should stay, fragrant it should be, and snap it should between your fingers. Then it is done.
Old herbalist's rule
The three tried-and-tested methods
Air-drying in a bunch
Tie 8 to 12 stems loosely into a bunch and hang it upside down in an airy, dark spot. Tying loosely matters so air can move through the bunch. Ideal for long-stemmed herbs like mint, lemon balm, sage and thyme. Duration: 7 to 14 days.
Flat on a screen or rack
Lay blossoms and single leaves in one layer on a clean sieve, a cooling rack or a frame lined with kitchen paper. Turn them once a day. This method is best for chamomile, calendula and anything small-parted. Duration: 3 to 10 days.
Dehydrator below 40 degrees
When the weather is damp, a dehydrator with adjustable temperature helps. Set it to no more than 40 degrees and leave the flap slightly open so moisture escapes. Check early, it goes faster than you think. Duration: 4 to 12 hours.
The oven is rarely a good idea. Most ovens do not hold cleanly below 50 degrees, and even 60 degrees destroy a large part of the aromas. If it has to be the oven, use the lowest setting, wedge a wooden spoon in the door and keep an eye on a thermometer.
How to tell when it is done
The test is simple and needs no device. Take a leaf or a stem and bend it. A fully dried leaf rustles and crumbles, a stem snaps with an audible crack rather than bending. If something still feels leathery or pliable, there is residual moisture in it, and that will later give you mould in the jar.
Reckon roughly with these times, depending on herb, thickness and weather:
- Delicate leaves
Mint, lemon balm and lemon verbena are often done after 3 to 6 days in the air.
- Robust leaves
Sage, thyme and rosemary need more like 7 to 14 days because of their firmer structure.
- Blossoms
Chamomile and calendula, dried flat, are usually ready after 5 to 10 days, depending on the thickness of the flower head.
Never dry unknown wild herbs for tea without having identified the species beyond doubt. Some medicinal plants have poisonous lookalikes, and mix-ups among the carrot family can turn dangerous. When in doubt: only harvest what you know for certain.
Storing it right so the stock lasts
Once the herb is truly bone dry, it goes away airtight. Screw-top jars, tins or well-sealing storage containers keep out moisture and light. Store the jars in the dark, a kitchen cupboard is better than the open shelf by the window. Light bleaches the colour and breaks down the active compounds.
A few small habits make the difference between a fragrant stock and a bland disappointment:
Keep it whole, crush only before brewing
Whole leaves keep their aroma longer than crumbled herb. Break the tea up in the cup, not already in the jar.
Label with name and harvest date
In six months you will not remember whether that was the lemon balm from CW 24 or the mint from CW 28. A sticker with herb and date saves you the guessing game.
Check again after two weeks
Look at the jars once after 10 to 14 days. If the glass fogs up inside or the herb clumps, it was not dry enough. Then dry everything again.
Stored properly, home-dried herbal tea keeps for about a year, comfortably until the next harvest. After that it is not spoiled, but the aroma fades noticeably. Conveniently, this rhythm fits the garden year perfectly: the last of last year's stock runs low just as the fresh mint shoots up again.
Mentha × piperita
- Familie
- Mint family (Lamiaceae)
- Standort
- Sun to partial shade, moist
- Saison
- Harvest CW 22 to 30, just before flowering
- Wasserbedarf
- Regular, dislikes drought
- Frosthärte
- Hardy to about −20 degrees
A simple house blend to start with
If you are mixing for the first time, keep it simple. A good everyday winter blend needs only three ingredients from your own bed: peppermint for freshness, lemon balm for the mild citrus note and a few chamomile flowers for warmth. Take about two parts mint, two parts lemon balm and one part chamomile, and you have a tea that both calms in the evening and wakes you in the morning.
If you like it more herbal, add sage or thyme, both classic herbs for the cold season. The one basic rule of every blend: only mix after drying, never before. Otherwise a still-damp herb passes its residual moisture to the dry one and the whole jar goes mouldy.
Common questions about drying herbs
Can I dry herbs in the microwave?
Technically yes, but it rarely pays off. The microwave heats in spots far too strongly and drives out the essential oils, precisely what you want to keep. For small amounts on a damp day it works in a pinch in 30-second bursts on a low setting, but air- or screen-drying always gives the better aroma.
Do I have to wash the herbs before drying?
Preferably not. Water lengthens the drying and rinses away part of the oils from the leaf surface. If the plants stood clean in the bed, a firm shake is enough. Only when there is visible soil splatter or aphids should you rinse briefly with cold water and then pat very thoroughly dry.
How do I know the tea is fully dried?
Do the snap test: a finished leaf crumbles between your fingers and a stem breaks with an audible crack. If something still bends softly or feels leathery, there is residual moisture in it and you need to keep drying. Better a day too long than a day too short.
How long does home-dried herbal tea keep?
Stored airtight, dark and dry, about a year, that is until the next harvest. After that it is not harmful to health but loses aroma clearly. A label with the harvest date helps you keep track.
Which herbs are best for beginners?
Peppermint and lemon balm are the most rewarding. Both grow lushly, are easy to harvest and dry effortlessly in the air. Chamomile is a bit more work to pick, but also beginner-friendly. With those three you already have a complete house blend.
Rechtlicher Hinweis
This article is no substitute for medical or expert advice. Only harvest plants you have identified beyond doubt, and consult a doctor for any health complaints.
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