Stored in ideal conditions, dried roots can retain maximum quality for more than a year before their potency gradually declines. The quality of dried leaves and blossoms begins to deteriorate after about six months. Highly aromatic herbs, such as tulsi and chamomile, are more susceptible to degradation than less-fragrant herbs, such as stinging nettles.
1. Timely Harvest: Always harvest herbs at their peak of potency. Check my book, The Organic Medicinal Herb Farmer, to figure out this peak for various plants. One of the first and most important things my herbal teacher and mother-in-law, Rosemary Gladstar, taught me is that dried herbs should look, taste and smell as close as possible to the plants when they were alive.
2. Careful Cleaning: To clean freshly harvested herbs, shake or brush them to remove debris. Washing leaves and blossoms before drying is not recommended as it can promote yeast and mold growth. Leaves you will use fresh can be rinsed and refrigerated before use. Roots that are to be dried or used fresh should be thoroughly washed to remove soil and other debris before using.
3. Quick Use: Some people prefer to harvest and use herbs fresh. Fresh herbs can be refrigerated or frozen until use. Frozen herbs can be susceptible to freezer burn, so consider vacuum-sealing, a great option for long-term storage of dried herbs, as well.
4. Or a Quick Dry: Herbs should be dried in the dark with good air circulation and temperatures not exceeding 100 degrees so as not to volatize aromatic compounds. Exposure to the elements can promote oxidation, which is detrimental to quality, so drying as quickly as possible is best. For home-scale drying, use food dehydrators or clean window screens on wood clothes-drying racks. Bundles of herbs can be tied with string and hung overhead in an airy place, but use care not to make the bundles too thick, which can slow drying.
5. Ideal Storage: Dried herbs should be promptly stored in airtight bags, jars or canisters, then kept in a dark, cool environment. One of the best home-scale dried herb storage options is to store herbs in airtight packaging in the freezer where the forces of degradation are slowed by low temperatures.
Jeff Carpenter is a farmer and co-owner, with Melanie Carpenter, of Zack Woods Herb Farm in Hyde Park, Vermont. The growing information presented here has been adapted from Jeff and Melanie’s excellent book, The Organic Medicinal Herb Farmer. The data comes from more than 15 years of records kept at their farm, partially augmented with data currently available in the industry.