In general, herbs need at least six hours of sun daily and good drainage. The soil need not be anything special; in fact, some of the fragrance and flavor of herbs can be diluted if they are grown in soil that is too rich. Herbs do not need a lot of fertilizer, either – they are usually happy in poorer soil. Mulching your beds with organic matter will help keep down weeds, as well as nourish the plants. Compost is one of the best mulches, and cheap, if you make your own. Water plants deeply, once a day, until they are established. Start small – don't try to grow everything as it can be overwhelming. A 4 x 8 bed makes a great beginning herb garden, and you'll have more than you need. Think about what plants you will really use and try them first.
Many herb plants can be grown in a pot, if you do not have the proper space. Be sure the pots have drainage holes, as overwatering kills many plants. Use a good quality potting mix. The size of your container will dictate how many plants you can grow in them. Aim for a 16-inch or larger diameter pot. Four to six plants can be planted in that size, with room for roots to spread. Larger pots will hold more water, too, which is critical during a hot, dry summer. For potted herbs, I use a fish emulsion fertilizer once every two weeks or so, as it is mild and organic. Annual herbs, as well as those you have just set out in the bed, can also benefit from a mild application of fertilizer every week or two until they are settled and their roots have taken hold. Tender plants – such as rosemary, bay, lemongrass, and pineapple sage – need to be grown in pots unless you live in zones 8 and up.
Annuals (plants that complete their life cycle in one year) are all fairly easy to grow from seed. Dill, savory, marjoram, savory, and parsley, for example, do best if directly sown into the garden. Basil, on the other hand, is tender and needs some heat to get it going. Either plant it four to six weeks before the last frost in pots, or buy basil seedlings from a reputable nursery or garden center. The best part of growing your own, however, is the fantastic number of varieties to choose from. Lime, cinnamon, Thai, and lemon are just a few of the varieties of basil you can grow.
The perennial herbs (plants that come up every year) – sage, tarragon, thyme, chives, mint, and lavender to name a few – are fairly hardy and able to withstand deep freezes, though it is always better to protect your plants with a layer of leaves or straw after the ground freezes. If you apply this winter mulch before the ground freezes, it can increase the temperature around the plant and encourage the plant to not go dormant, and you run the risk of losing it. A good practice is to grow them in a protected bed, surrounded by stone and close to a building (both of which help to retain some thermal mass) and also shelters them from drying winds.
Don't jump the gun and set your plants out too early. Aim for the frost free date for your area. Tender plants should not be left outside if the temperature is going to dip below 50 degrees. Even putting them in an unheated garage is preferable to leaving them out. Don't forget to harden your plants off – whether you get them from a nursery or grow your own. Put them outside, in a protected, semi-shady area, for a few days. Too much sun or wind can burn the plants until they are acclimated to the weather outside. Then, pop them in the ground, water well, and bask in the joy of a well-planned garden!