I print this information on a somewhat regular basis, some of it will apply now to the fall season we are about to enter. Other iinformation is for summer, so take the information most useful to your situation now.
Here are some things to remember:
- Herbs are at their best when they're fresh-picked. For daily use, pick just what you need. Wrap herbs in a damp paper towel and put them in a tightly-closed plastic bag in the refrigerator.
- Long-stemmed herbs (thyme, rosemary, oregano, savory, dill, fennel) can be kept on the kitchen counter for a few days. Strip lower leaves for immediate use and put the stems in a narrow-necked vase filled with water, out of the sun.
- Herbs produce their most intense oil concentration and flavor after the flower buds appear but before they open. Harvest at this time for most uses. Blooming plants such as basil and oregano may still be suitable for vinegars, however.
- Harvest annual herbs until frost, making as many successive harvests as possible without damaging the plant. Don't cut too near the ground, for lower foliage is necessary for strong, continuing growth. At the end of the season, harvest the entire plant.
- Harvest perennial herbs until about one month before the frost date. Late pruning encourages tender growth that may be killed by the frost, and plants need the regrowth to see them through the winter.
- Harvest tarragon or lavender flowers in early summer, then cut the plants to half their height to encourage fall flowering.
- Harvest herb seeds (mustard, fennel) as the seed pods darken and dry, but before they burst. Secure a paper bag over the seed head to complete ripening, then cut the stem and hang the bag for further drying.
- Harvest herb roots (bloodroot, chicory, ginseng, goldenseal, horseradish) after the foliage fades.
For more about harvesting (and using!) your herbs:
- The Herb Society of America's Essential Guide to Growing and Using Herbs, by Katherine Schlosser
- Your Backyard Herb Garden, by Miranda Smith