Harvesting and Storing Herbs

by James A. Duke, Ph.D.
The Green Pharmacy

Okay, so you've got a big peppermint patch, or whatever, growing in your garden or on your windowsill. Now what?

First you must harvest your herbs. You can snip off leaves and use them as needed. Taking a cue from the American Indians, the romantics among us like to thank the herb for serving us and apologize for mutilating it.

Down in Panama and Peru, I listened as Indian shamans sang long chants to the herbs they were about to harvest, often while facing the East. When I'm not in a hurry, I remember that the plants, too, have lives, and that their lives sustain ours.

In fact, the more we clip the leaves of medicinal plants, the more medicinal they become. This makes sense botanically because herbs' medicinal constituents are basically part of the plant's self-protection system. Harvesting the leaves makes the plant respond as if it's under attack (which it is), so it produces more of what protects it. Studies have shown that infections, insect infestations and leaf-plucking, among other attacks on the plant, increase the levels of some of the same chemicals that we view as medicines.

Collection Times

Although some herbalists argue for harvesting herbs early in the morning while there is still dew on them, I disagree. That dilutes the herb with water, meaning that it has proportionately more water and less chemical until it's dried. In my view, you get the greatest concentration of plant chemicals and the least water when you collect leaves during a hot, dry day, but before the leaves have wilted.

Roots are best collected in spring or fall. Bark may be collected in spring, especially if the compounds you seek are in the living bark. If you're collecting seeds for food, I recommend that you get them before they have dried out and hardened. But if you're harvesting them to plant next year rather than to use immediately, you may want to wait until they've dried out.

Feel free to use herbs fresh, especially in cooking. Fresh culinary herbs and spices almost always taste best. You can also freeze them, dry them or use them to make tinctures. (When harvesting fresh culinary herbs, I generally use a plastic bag to help retain the moisture.)

Preserving the Goods

If you intend to preserve your herbs for future use, it's cheaper to dry them. Collect them in a brown paper bag rather than a plastic bag, and write the name of the plant and the collection date on the outside of the bag.

If you don't stuff it too lightly, many herbs can be dried right in the bag. I always make a run through my herb garden with paper bags before the last killing frost, collecting herbs for my winter medicines, soups and teas.

Check your brown-bagged herbs after about a week, and if they are not clearly drying - becoming papery and crumbly - spread them out on newspapers or clean wood or screen in a dry, shaded area so that they can dry out before mildew attacks.

When it comes to success in drying, a great deal depends on your local weather conditions. In arid weather, herbs may dry too rapidly, especially in direct sunlight. In humid and especially in foggy weather, you may have to apply heat by baking the herbs in an oven to get the moisture out.

Once dried, herbs can be kept in paper bags or stuffed into plastic bags. You can also use glass jars with lids.

Light, heat and oxygen are the enemies of herb potency, so store your herbs in a cool, dark place, like a cellar or cupboard far from any heat source. To minimize the oxygen around stored herbs, fill your containers as full as possible and move the herbs to smaller containers as you use them.