ShareThe flavor and aroma of herbs comes from the essential oils contained in the leaves, which varies depending on the time of day and the stage of the plant’s life cycle. The best-quality dried herbs are picked when the essential oil content is at its peak, which is when the plant is producing only leaves, not flowers or seeds.
You probably harvested your herbs repeatedly throughout the summer, in which case you noticed that they send out new shoots each time they’re cut. If left uncut long enough, they start to flower and set seed. Try to time harvesting your herbs for when there is plenty of lush green growth but when flowers haven’t yet formed. It’s best to do this in early fall; as the days get shorter, most herbs enter the flowering stage more quickly in an effort to set seed before the end of growing season.
The heat of the sun causes essential oils to vaporize and fill with air with their aroma. For this reason, it’s best to harvest herbs in the morning while the leaves are still saturated with flavor. Not too early, however, because they won’t dry as easily when they’re covered with dew. Aim for the brief window when the sun has just hit them and the dew has dissipated. (Read more.)