German chamomile (Matricaria chamomilla) produces most of its flowers between June and August, and if you have established plants in your garden this is one of the most rewarding harvest periods of the year: a daily or every-other-day picking of the small daisy-like flowers that, dried properly, fill a jar with something that will serve you well through the coming year.
The Right Moment to Harvest
Chamomile flowers should be harvested when the white ray petals are fully open and beginning to reflex back (bend backward and downward from the yellow center disc). This is the moment of maximum volatile oil content and medicinal potency. Flowers harvested before they are fully open have lower concentrations of the active compounds. Flowers harvested when the petals have been fully reflexed for a day or two are past their best.
Harvest in the morning of a dry day, after any dew has evaporated. The volatile compounds are most concentrated in the warm morning before the heat of the day begins to evaporate them. A chamomile rake (a comb-like tool designed for harvesting chamomile flowers efficiently) is useful if you have a large planting; otherwise harvest by hand, pulling the flowers from the stalks with a twist.
How to Dry It Well
Chamomile drying is where most people go wrong. The flowers contain high concentrations of volatile oils (the characteristic apple-like scent) that evaporate with heat. Drying at too high a temperature drives off the very compounds that make the herb medicinally useful. The correct temperature is 30 to 35 degrees maximum, in good airflow and away from direct light. Spread the flowers in a single layer on a drying screen or in a dehydrator at its lowest setting. They should be dry and crumbly (not moist or pliable) within 24 to 48 hours at the right temperature and airflow.
Storing and Assessing Quality
Well-dried chamomile flowers should retain their strong, characteristic apple-honey scent for at least twelve months when stored in airtight, opaque containers. If the smell has faded to a vague dusty quality, the medicinal value has largely gone with it. This is the most reliable quality test for any aromatic herb.
The Herbalist Codex app has the full chamomile profile alongside its growing and harvest guidance. A jar of properly dried homegrown chamomile is one of the most satisfying things in the home apothecary.