Herb Gardening and Soil Choices

Gardening in difficult circumstances has had beneficial consequences, for it forced me to examine and question accepted gardening practices and to revise them according to my needs. This is a healthy, even exciting exercise, very rewarding for those who enjoy challenges and solving problems. Some of the most widely held notions do not, I have discovered, work under all circumstances. For instance, clay soil should not always be dug out and replaced by “better” soil; in fact, digging in general can often be avoided altogether. And mulching can sometimes lead to more problems (such as slugs) than it solves.

Growing herbs from seed is an economical way to have a variety of plants for general use or for landscaping. If you plan to make herb vinegars and jellies with basil, for instance, or use parsley as an attractive edging plant in the bed or border, it makes sense to grow your own plants from seed. For a fraction of what it would cost you to buy them, you can raise a virtual army of seedlings.

You should know, however, that not all herbs are easy to start from seed, and others can’t be grown from seed at all. Seeds of some plants, like parsley, germinate very slowly. Certain seedlings, like those of rosemary, thyme, and lavender, are slow growing, a disadvantage in regions where summers are short. And some cultivars or strains (named plant variations), like Achillea ptarmica ‘The Pearl’, as well as all the mints, do not come true to type from seed (in other words, plants grown from seed do not look exactly like the parent plant).

If you’re just beginning with herbs, it’s wise to start with the easy ones first; your success will give you confidence to try the more demanding ones later on.

The seeds of most herbs will germinate readily in the 70-degree range, the approximate indoor room temperature. I put down the desired germination temperatures in this column; they usually range from 55 to 80 degrees. Those herbs that germinate best at lower temperatures, like chamomile, are sown directly in the ground outside; those in the middle range, from 60 to 70 degrees, are sown either indoors or outside, depending on their growth rate. Herbs requiring higher temperatures to germinate, like the basils and sages, are usually started indoors.

I occasionally sow perennial herbs outdoors in a coldframe in the late summer or fall and plant out the resulting seedlings the following spring. I use this method if I have limited space indoors or if I’m unsure of the plant’s germination requirements. The main advantage is that you only need a suitable south-facing site for the coldframe and friable, early-warming, well-drained soil inside. The rest is up to nature, since once the seeds are planted, nature alone will determine when the soil has reached the magic temperature for germination to occur. It’s always a thrill to find seedlings in the spring, sprouting on last fall’s bare ground. It is important, though, to be patient. If the ground is still bare, don’t be alarmed and don’t disturb the soil. The seeds may still be viable, just waiting for warmth to germinate.

Herbs, with a few exceptions, thrive in well-drained garden soil, moderately enriched. “Well drained” or “sharply drained,” repeated like a mantra throughout this book, means that the soil is loose and friable; in other words, you can scoop up a handful and it will be crumbly and easy to pour from your hand. The soil should allow water to penetrate its surface and reach the plant’s roots before draining off; there should never be any standing water around the root crowns of plants. The loose soil particles encourage the production of a strong root system, just as compacted soils discourage good root growth. If you plant herbs in the soil conditions they prefer.