Medicinal plant harvest calendar: timing, identification and drying basics

Month by month, learn what to harvest, which plant part to choose, how to dry herbs, and when wild picking is not worth the safety risk.

Harvesting your own medicinal plants can reconnect you with seasonality and improve freshness, but it only makes sense when identification, legality and drying quality are reliable. A beautiful plant picked in the wrong place, at the wrong stage or dried badly can be ineffective or unsafe.

Golden rules for the gatherer

• Harvest in dry weather, after dew evaporation (10am-12pm) and before peak heat
• Avoid roadsides, treated fields and polluted areas (at least 100 m from a road)
• Identify with certainty (in the slightest doubt, abstain) — a botanical guide is essential
• Never take more than a third of a station, never protected species
• Respect local rules, private property, protected species and pesticide risks

The calendar below is a temperate-climate guide. Local climate, altitude and seasonal weather can shift harvest windows by several weeks.

Month by month

March-April

Buds (blackcurrant, birch, pine), tender nettle leaves, dandelion (young leaves, flowers and roots), violet, primrose, daisy.

May

Hawthorn in bloom (flowering tops), meadowsweet in buds, black elderberry flowers, lemon balm in early flowering, plantain.

June

Linden (bracts at the beginning of flowering, over only 3-5 days a year), Roman chamomile, Provins rose, raspberry (leaves), yarrow.

July

Lavender (just before full flowering), thyme, rosemary, savory, hyssop, St. John's Wort (June 24 traditionally, St. John's Day), common verbena.

August

Sage, lemon balm in second cut, basil, peppermint, calendula.

September

Elderberry (berries at full ripeness), hawthorn (haws), wild rose (rosehips), hops (female cones), angelica.

October-November

Roots: dandelion, valerian, burdock, gentian, marshmallow. Cold concentrates actives toward the root.

At what stage to harvest each part?

• Buds: before bursting, late winter
• Leaves: just before flowering (maximum active concentration)
• Flowers: at the beginning of flowering, early morning
• Flowering tops: full bloom, tender part only
• Fruits/berries: at full ripeness
• Roots: autumn or very early spring, outside vegetative period

How to dry properly

Drying is the most critical step. Bad drying = mold or essential oil loss.

• In the shade, in a ventilated, dry room, at 25-35 °C maximum
• Spread on a muslin-covered frame, or in small bunches hung upside down
• Never in direct sun (destroys pigments and essential oils)
• Never in the oven except at very low temperature (35 °C max)
• Plant is dry when it snaps cleanly between fingers (5-15 days depending on part)

What to write on each jar

• Common name and Latin name
• Plant part harvested
• Harvest date and location
• Drying date and any unusual weather conditions
• Intended use and safety notes, especially if the plant has lookalikes

Storage

Store in opaque glass jars (or sheltered from light), labeled with date and harvest location, in a dry, cool place. Average shelf life: 1 year for leaves and flowers, 2-3 years for roots. Beyond that, actives degrade.

Frequently asked questions

Should one really account for the moon?

It's an ancestral herbalist tradition, partially validated by some modern studies on compound content variations. If it speaks to you, follow it; otherwise, time of day is more decisive.

Can fresh plants be frozen?

Yes for some (lemon balm, basil, parsley), often in oil or water ice cubes. Not ideal for medicinal plants because thawing alters many actives: prefer drying.