BY KENNETH SETZER
As published in the Miami Herald, 10/13/15.
As gardening in most of the country slows down for fall, South Florida is waking up. Now we can plant some of the temperate herbs our northern friends and family have enjoyed all summer long. Here’s how to get started, whether you have a big garden or like to keep things small by sticking to containers.
▪ Start at the bottom. The best soil for your plants is the one that meets the plants’ particular needs. Many herbs prefer soil that has neutral to acid pH levels. That means we may need to amend our alkaline Florida soils to raise acidity and lower pH. Adding sphagnum peat moss to the upper layer of soil increases acidity, or add ammonium sulfate to cover larger areas. Follow the label instructions if you add ammonium sulfate — more is not better and can burn tender plants. I avoid using it in pots, as salts can accumulate.
Raised garden beds are the best way to contain and control soil nutrients. Make them from wood or cinder blocks, or buy them in kit form.
▪ When to plant. Exactly when isn’t easy to answer, particularly given the last couple of years of wet, warm winters and drier than usual springs. Wait until the temps cool off a bit and heavy storms subside, probably this month.
▪ Starting out. You can buy seed starter trays or improvise. Toilet paper cores placed upright (easy to write on) and clear plastic cherry tomato containers make perfect seed starters. The seedlings will be very delicate and can burn easily from too much sun and insufficient water. Or buy transplants from a nursery and get a headstart.
▪ Container life. Herbs are traditionally grown for seasoning or other uses involving small quantities, so you don’t need many plants. Many herbs thrive in small containers in which they can be situated for best sun exposure, as well as to accent your garden, patio, balcony or nearly anywhere with sufficient light.
Remember that containers will heat up in the sun without surrounding soil to dissipate the heat, so pay special attention to the soil’s moisture. I generally mix potting soil, compost, perlite for drainage and maybe some sphagnum moss. Prepackaged potting soil alone gets clumpy, which starves roots of oxygen and makes it difficult for seedlings to penetrate the soil.
Frequent watering washes nutrients from pots, so eventually, adding a general fertilizer might help, or better still, add compost.
Many of these plants prefer cool summer conditions, which we need to replicate during the winter. Growing herbs is just like growing vegetables — the plants don’t care what we call them, as long as we meet their horticultural needs.
Mint tea, anyone? This cute perennial is easy to grow and attractive with serrated olivey green leaves and reddish stems. Mentha species include spearmint (M. spicata), peppermint (M. piperita) and varieties that hint of chocolate or citrus. Plant in bright shade to get some sun. Mint likes damp soil but isn’t picky. Harvest leaves at midday when mint oils will be strongest. After flowering, leaves will taste bitter, but the flowers can be consumed as well. Watch out for runners, which may overtake a garden. Mint is nice in pots, which will reign it in and grows to about 24 inches tall. Pinch mint back to encourage bushy growth.
Petroselinum crispum likes it cool, so wait until late fall or winter to plant seeds shallowly in pots or in the ground. Thin out seedlings to about six inches apart. Parsley can yellow for numerous reasons, one of which is crown or root rot. Give parsley morning sun exposure, which is a good time to water, allowing the soil to thoroughly drain, but not completely dry out, in the sunlight. Avoid crowding parsley, which inhibits air circulation. P. crispum is known as “curly leaf” while P. crispum neopolitanum is the “flat-leaf” parsley preferred for cooking. When harvesting, you may have to compete with black swallowtail butterflies.
Rosmarinus officinalis sends up 2- to 3-foot-high stems with short, narrow leaves resembling juniper. This bushy perennial grows best from cuttings. Plant in full sun. Likes slightly moist, but very well-draining soil with some added sand. Good candidate for containers. The leaves can be harvested any time, and their smell is enjoyed by simply walking past them.
Silvery soft leaves are characteristic of Salvia officinalis, which normally does not like high heat and humidity. Start it in fall in a very well-draining clay pot with sandy, loamy soil, with lots of sun. It’s best to start sage from cuttings or transplants. Keep young plants moist, but let them drain well between watering. Mildew may be a concern with sage, so a layer of pebbles around the plant can help.
People often ask if a ginger plant can be grown from the “hand” of ginger available at supermarkets — and yes, it can. Zingiber officinale grows from a tuberous rhizome. Pick one that is nice and firm, not mushy or shriveled, and plant a couple of inches deep right in the garden or in a deep pot with rich soil. Ginger prefers filtered sunlight and lots of humidity, but not soggy soil; frost will kill it. Compost mixed with sandy potting soil works well. You may not get intense growth until spring, but you can harvest the rhizome and separate its “fingers” just about any time. They can be used in food or planted for more ginger.
Exotic for most regions, easy for us. Turmeric (Curcuma longa) is in the ginger family and grows similarly to ordinary ginger. Used for the intense orange yielded by its rhizome and in curry, turmeric is finally being recognized for possible medicinal qualities. It has proved quite hardy in my garden in pots and in the ground. The rhizomes have sprouted with green, even when stored on my patio. Morning sun is fine, but shelter turmeric from direct exposure otherwise. Mulch helps retain soil moisture, especially in a pot. While the tropical foliage and flowers are extraordinary, the rhizomes are the only part consumed. When the foliage eventually dies back, dig up the rhizome; divide it to eat and/or grow more plants.
My wife successfully grew basil on a fire escape in New York City. But I’ve had trouble with it in Miami. Ocimum basilicum is a short-lived annual; its leaves can be used fresh or dried. Basil prefers direct morning sun tempered with afternoon shade. Fall temperature doesn’t seem to be our problem; drainage does. I’ve germinated basil seeds easily, only to have the tender seedlings wither and die. It seems basil hates wet feet. Try it in large clay pots using potting soil mixed with lots of perlite and sand to encourage draining. Once it is established, try adding compost and mulch to the top of the soil. If the leaves yellow, the soil may be too wet; repot the plant to save it. Pinch its inconspicuous flowers to encourage more leaf production.
Melissa officinalis is in the mint family of Lamiaceae, so it should thrive in South Florida. Lemon-scented leaves are fragrant and flowers are attractive to bees. Pinch it back to keep it bushy; it grows to about two feet tall. Keep it in pots and deadhead flowers before they set seeds to avoid lemon balm taking over. Lemon balm doesn’t mind a good haircut and responds with dense bushiness. Besides possessing many medicinal qualities, lemon balm supposedly repels mosquitoes, but does anything really? In the kitchen, make tea from lemon balm, sprinkle it over salads or use it to flavor vinegar. Grow it from seeds, cuttings or transplants.
The refreshing taste of cilantro (Coriandrum sativum), also known as coriander, always reminds me of great Mexican food. Warm weather speeds up cilantro’s life cycle, so fall and winter here should be ideal, giving more time for you to harvest the delicate foliage. Provide excellent drainage and be wary of overwatering; grow it in pots to ensure soil is loose. Cilantro is susceptible to mildew. Even in fall, direct sun may be too harsh for the cool, bright shade cilantro prefers. A completely different species is culantro (Eryngium foetidum), which tastes like strong cilantro and is adapted to the Caribbean. If you can find culantro, it should fare well in our climate.
Anethum graveolens leaves produce the herb dill, while its seeds can be employed as a spice. Dill prefers neutral to slightly acid soil, lots of sun and soil that is loose and drains well. Adding compost for nutrients and sand and perlite for drainage will help keep your potting mix airy and loose. Dill does not like its deep roots disturbed, so transplants may not survive. Grow it from seed in a deep pot. It can grow to 2 or 3 feet tall, with feathery green foliage topped with mustard-yellow umbels of flowers.
Origanum vulgare, sometimes called wild marjoram, is also in the mint family and can be grown from seed or cuttings. Pinch it back to keep it short and bushy. Oregano likes it warm and dry (think “Mediterranean”), with lots of sun but some protection from the harshest late-day light. Make sure that soil drains well, and water oregano only when the soil feels dry. Lots of sweet and spicy cultivars are available that go beyond the jarred, dried herb we are used to.