FIMBY: Grow culinary herbs in containers

This is another in our “Food in My Back Yard” series, dedicated to edible gardening.

Having fresh herbs on hand makes a huge difference in flavor and versatility when cooking from your backyard garden.

Herbs are among the easiest edibles to grow in containers, which puts a kitchen herb garden within reach, even if all you have is a balcony.

There are, however, some key points to consider before uniting an herb transplant -- and here I highly recommend transplants -- with its future pot or barrel.

1) Is the herb an annual, perennial, biennial -- or even a rhizome or tuber? The majority of herbs are perennials. Annuals, such as basil and cilantro, will last less than a year, since cilantro (surprise!) doesn't like hot weather, and basil is killed by frosty temperatures. Dill and chamomile are other herbs that are one-year-and-out; in our climate, they're best grown in late winter through mid-spring.

2) How big does the plant get? A full-size rosemary can grow 5 feet tall and 4 feet across -- a better choice as a landscape plant. But some varieties are smaller and easier to control in pots,  including "trailing" varieties. Lavender also can grow quite large, depending on the variety. Plant tags will note how big a transplant will get. Choose a container that will hold a mature plant comfortably. And make a note to keep the plants trimmed, avoiding that overgrown "rangy" look.

3) What are the water needs for this herb? Rosemary, for example, prefers drier soil once established, and shouldn't be planted alongside herbs that need more water, such as basil. It's susceptible to root rot if drainage is poor. Sage and thyme also do not like too much water. Mint, by contrast, prefers moist soil and less sun exposure than many herbs.

4) Is this plant a potential thug? Speaking of mint, it is a notorious garden invader, growing via underground rhizomes, so it almost always is recommended as a container plant. But even putting two mints together in a pot can be a problem, as one can eventually dominate the space. Other common, less-nasty interlopers: Borage, which reseeds easily,  lemon balm, yarrow and oregano. Don't ignore them.

5) Can it be allowed to flower? Certain herbs -- basil again -- will turn bitter when they flower or "bolt," as they anticipate the end of their life cycle. So that maintenance, to keep buds clipped, has to be factored into its care. But lavenders are grown for their flowers, and the flowers that appear on scented pelargoniums are part of their appeal.

Note that pollinators love many herb flowers, so I grow some herbs for my kitchen, but let others flower just for the bees and other insects to enjoy. Along with basil, fennel, cilantro (coriander) and borage are good choices for pollinator herbs.

6) Does the spot for the container receive 5 to 6 hours of sun per day? That's the minimum for most herbs. If sunlight shifts too much in your space, put the container on a little platform with wheels, so it can be moved to the prime spot.

Preparing containers

Any plant container, whether plastic, ceramic or wood, should have plenty of drainage holes in the bottom. Do NOT put rocks, gravel or pottery shards in the bottom. Fill the container with a good potting soil; avoid native garden soil or "planting mix." Mix in some perlite (those white puffy bits) if the potting soil doesn't appear to have any; it will help drainage and root development. I also like to add some compost or worm castings. Fill the pot to within 2 inches of the rim with soil before starting to plant.

Suggestions for herb groupings in containers

Summer annual trio: Genovese basil, "Amethyst" or "Red Rubin" basil and "Emerald Towers" basil. These three will give the cook a range of uses: The Genovese is a classic sauce and pizza basil, while the purple varieties are beautiful in panzanella and other salads. "Emerald Towers," if you can find it, is upright, compact and slow to bolt.

Thyme trio: I have killed more thyme than just about anything I've tried to grow in pots, and am convinced it doesn't like to play with other herbs. It is a perennial, but a short-lived one. Group an English or French thyme, a German thyme and a lemon thyme in a container, and you'll have plenty of thyme on your hands. Don't overwater it!

Mediterranean collection: Winter savory, Italian or Greek oregano, lavender and culinary sage.  These perennial plants are all low-water herbs, and won't crowd each other too much if grown in a half-barrel. Look for a dwarf lavender. For the sage, look for Salvia officinalis, rather than the many autumn sages (Salvia greggii) that are used in landscaping. If you'd rather grow tarragon than the lavender, prepare for it to die to the ground in winter, but it will re-emerge.

Cool-season group: Cilantro (try a few staggered plantings), chamomile and dill. When these are spent, replant the pot with basil and summer savory (which is an annual).

Some single-herb container suggestions

Some varieties of these plants in the right circumstances can be planted with others, but I think they do better solo:

-- Chives. A great cut-and-come-again culinary accent.

-- Rosemary. For all the reasons listed above.

-- Parsley. This ubiquitous culinary herb is a biennial, which means it lives two years and dies. Go with the flat-leaf Italian variety or the curly-leaf type, but check the roots of any transplant before you buy it to make sure it's not aged. Better yet, grab a sixpack of parsley and plant the whole group (I never have enough of it). Plant more next year to stagger the crop.

-- Pineapple sage (Salvia elegans). This is a wonderful plant, one of my favorites, with pineapple-scented leaves. It can be grown in the ground but would do best in a half-barrel-size container; make sure drainage is excellent. It will reward you with spectacular red flowers in early fall. It also spreads via runners just under the surface.

-- Fennel. The plant is used as a vegetable (bulb) as well as an herb (seeds, flowers and pollen). It's a perennial, low-maintenance and can grow quite tall. But it's not friendly to the rest of the garden -- it's "allelopathic," meaning its chemistry can inhibit other plants. A large terra cotta pot is perfect for it.

And now for something completely different

-- Ginger. Yes, you can grow ginger in Sacramento, though it is cold-sensitive, and requires somewhat humid conditions, so keep it where it gets afternoon shade in summer. Look for organic-grown rhizomes, which have not been treated with growth retardant. Ginger grows in a line, not a clump, interestingly, so remember that when choosing its container. For best flavor, harvest in winter after the top has died back completely, and replant part of it for next year. 

For more information on herbs: