Growing herbs yourself is an effective way of having unusual herbs available whenever you want. Whether you choose to make them part of an existing garden, or to have a dedicated herb garden doesn’t matter.
The first thing to decide is the size of the plot you’re allocating to your herb garden. Most herbs need about one square foot to grow successfully. So something around fifty square feet would let you grow around fifty different types of herbs. You need to keep annual and perennial plants separate and it’s a good idea to “make a map” of what you plant where. Markers can easily get moved, knocked over, displaced etc.
One of the main things you need to consider for a herb garden is soil condition and drainage. Drainage probably more than anything will be the deciding factor on how successful your efforts are. The fertility of the soil can always be improved by the addition of natural compost. If your soil waterlogs easily then you will need to dig down a good eighteen inches and lay a bed of stones several inches thick before replacing the topsoil. It’s hard work but your garden (and you) will reap the benefits. When you replace the topsoil fill to a higher point then the original bed to allow for settling. Even if your soil is fertile, it’s a good idea to mix in a good amount of compost as not only will it improve the fertility, it will help with moisture retention.
Nearly all herbs can be grown from seed. The best time to plant seed is late winter in shallow boxes. When spring arrives, transplant the seedlings into your garden. Some seeds, such as anise, coriander, dill, fennel, and biennials should be sown directly into the garden, as they do not transplant well. Don’t sow the seeds too deeply. As a tip, mix the seed in with some light sand before sowing. It will make even sowing easier. If you are going to grow mint (of any variety) it should be grown only in a container. Mint is very aggressive and will take over your garden if you let it.
Perennial and biennial herbs will need winter protection. Many, if not most, herbs are quite shallow rooted. You will need to mulch with straw, or anything else suitable, to a depth of approximately four inches. The mulch should not be removed until the plants show signs of spring growth.
Fresh leaves may be picked as soon as the plant has enough foliage to maintain growth. The best time to harvest your herbs is in the morning after the dew has disappeared, and before the sun has become too hot. To ensure good oil content, pick leaves or seeds after dew has disappeared but before the sun becomes too hot. For dry, winter use, harvest leaves before the flower buds open. Pick the seed heads as the color changes from green to brown or gray. Wash dirty leaves and seed heads in cold water; drain thoroughly before drying.