Creating new plants from the ones already growing in your garden is called propagating. Like harvesting, propagating can take place throughout the garden season. Herb gardeners who want to collect seeds for next year’s harvest leave several plants to do nothing but set seeds — botanical brood mares for next year’s garden. Diversity is the key to a healthy gene pool, so save seeds from more than one plant. Some plants are genetically disposed to be more tolerant of drought, cold, heat, diseases, and pests, so designate your healthiest plants as “breeders.”

You can easily start angelica, anise hyssop, basil, borage, burnet, calendula, catnip, caraway, chervil, coriander, dill, fennel, feverfew, German chamomile, lady’s bedstraw, lemon balm, lovage, marjoram, nasturtium, oregano, parsley, summer savory, winter savory, and wormwood from seed. Some herbs — mints are the classic example — are nearly impossible to start from seed. Either the plants rarely flower or their seeds are sterile. Most variegated plants (cultivars with foliage marked with colors other than green, such as cream or white) can’t be grown from seed, which is one reason that many variegated herbs are more expensive.

Collecting seeds is the same whether you’re going to eat or plant your harvest. Storing is a slightly different matter. Keeping your seeds in a dormant, or inactive, state is essential. Those seeds may look dead, but the embryos inside are just napping. As with all babies, you want to keep them that way. Seeds saved for sowing need to be dry and clean, and stored in a cool, nonhumid location. Too hot or too cold, too wet or too dry and the embryo that each seed contains will either die or sprout prematurely. Your refrigerator is an ideal storage place. Use paper envelopes — don’t forget to label and date them for each batch of seeds and then place all the envelopes in a sealed glass jar. You can add one tablespoon of dried milk (wrapped in unscented tissue) to each jar as a desiccant.

If you’ve saved seeds, you may need to apply some special treatments before they’ll sprout — or sprout quickly:

• Scarification: Large seeds with very hard seedcoats germinate far faster if you scarify, or scratch, them. Nick them with a knife or rub them on sandpaper or emery board.
• Soaking: Some seeds, such as parsley and scented geranium, germinate far faster if you soak them in water overnight before you sow them.
• Stratification: The seeds of some perennial and biennial herbs, such as sweet Cicely, must be chilled, or stratified, in order for them to germinate. Storing seeds in the refrigerator for two months takes care of most seeds’ chilling requirements.

Multiply By Dividing

Dividing an established perennial herb is a quick way to turn one plant into several plants that are exactly the same as the one you’re growing. Click here for instructions on dividing plants

Common herbs that don’t mind being divided include aloe, artemisia, betony, catnip, chamomile, chives, comfrey, costmary, elecampane, feverfew, garlic, germander, ginger, horehound, horseradish, hyssop, lady’s bedstraw, lemongrass, lovage, madder, marjoram, marsh mallow, mint, monarda, oregano, orris, pennyroyal, roman chamomile, rue, sage, santolina, sorrel, southernwood, sweet Cicely, sweet woodruff, tarragon, valerian, violet, winter savory, wormwood, and yarrow. Be sure to get the divisions back into the ground quickly and give them plenty of moisture until they’ve taken hold in their new location.

A Clip Off The Old Block

Rooting cuttings is an ideal method for increasing your supply of plants, especially hybrids, cultivars whose names you lost long ago, and species that don’t divide or grow from seed easily. You can take stem cuttings or tip cuttings (the green, succulent sections from the end of nonflowering stems) anytime your plant is growing actively (so don’t wait until late fall, when plants are moving into dormancy).  ....read more