Basil
Basil smells and tastes spicy and fresh and is often used in Italian, Asian, and other cuisines. Native to India, Africa, and Southeast Asia, all basil species (Ocimum spp.) belong to the Lamiaceae (mint) family. Different basil varieties are used around the globe and each basil's unique flavor compliments the regional dishes it can be found in.
Characteristics
Basil is available in wide selection of scents and flavors due to the varying types and quantities of essential oils contained in each variety. Basils can also be quite different in size and appearance.
The many varieties of basil can be generally divided into four groups – sweet green, dwarf green, purple-leaf, and scented leaf.
Some varieties, like 'Greek Column-Lesbos', can grow quite large, reaching up to 3 feet tall. Larger basils do better planted in a flower bed or garden while miniature basils, like 'Dwarf Greek basil' and 'Spicy Globe', are great for growing in a container. 'Marseillaise Dwarf' is a French basil which some claim has the best flavor of all varieties. This basil is also quite compact; it grows to only a foot tall which makes it perfect for just about any space.
Leaves can be either green or purple, and can be flat or ruffled. Purple-leaf varieties like 'Purple Ruffle' and 'Osmin' can add a unique color to your dishes; add some colorful leaves to salads for a fun twist, or steep them in white vinegar for beautiful color. Basil's attractive flowers can also be used for cooking and can be found in purple, pink, or white depending on the variety.
Sweet basil is commonly used in Italian cooking and is the most popular type in America. Sweet basils like 'Genovese' and 'Lettuce Leaf' will provide you with large, sweet green leaves that are great for using in pesto. Even among the sweet varieties there are differences—'Sweet Broadleaf' has medium leaves and the mature plant is about 18 inches tall, whereas 'Genovese' has larger and more fragrant leaves and reaches a mature height of about 2 feet tall. 'Napolitano Mammoth-Leafed' has very large leaves. If you're looking for smaller leaves, shop for 'Fino Verde Little-Leafed' basil and other miniature-leaf types.
Beyond sweet varieties there are some exotic and interesting basil flavors to investigate; for example, lemon or lime varieties offer a mild citrus aroma. In Indonesia, lemon basil is often used fresh served with vegetables, poultry, or fish. Lime basil is great for marinades and sauces as well as deserts like sorbet or shortbread cookies.
Thai basil has a spicy flavor and is common in Asian cooking. It's especially useful when making Thai dishes like Tom Yum soup or spring rolls. 'Mexican Spice', also called cinnamon basil, is another spicy basil and has a subtle cinnamon taste and fragrance. It's excellent in chutneys and sweet dishes, particularly those using pumpkin, squash, or sweet potato.
Basil can even be found in chocolate, licorice, camphor, and anise-scented varieties. You needn't limit yourself to just one variety of basil—plant as many as you like and see which works best in your garden and which flavors you like in your kitchen.
Planting and Care
Most basils are annuals in Florida, but a few behave as perennials. Basil grows well in Florida's warm climate; plant it from seed in either the early spring or fall, in containers or in your herb garden. It prefers sun (with a bit of afternoon shade to protect it from the heat) and moist, but well-drained soil. The plants are sensitive to frost, so provide protection on cold nights. The leaves of many varieties will turn black and drop off the plant when temperatures drop below 40°F.
Growing basil in raised beds or containers is a good way to provide adequate drainage and avoid having to bend over to harvest leaves. When planting in the spring, wait until the last frost has passed and night time temperatures are above 55°F. When planting basil from seed be sure to thin out seedlings so that they are spaced about 10 inches apart. Using mulch can help conserve soil moisture, regulate soil temperature, and suppress weed growth around your plants.
Basil can be harvested as needed; new leaves will have the best flavor. Pinch the growing points out for use in the kitchen. This will help keep the plant compact and will extend the harvest season. Regular harvesting will encourage branching and the production of new leaves.
Allowing the plant to flower and set seed will shorten its growing season. If you are more interested in basil for culinary uses rather than ornamental, pinch off flowers as they form to focus the plant's energy on making leaves. However, allowing your basil plant to flower can be useful if you are interested in collecting seed from it. If you do allow basil to flower, it's important to keep a distance of 150 feet between different varieties to prevent cross-pollination.
To save seeds from basil, let the flowers "go to seed"—that is, leave them on the plant until they die, allowing the seeds turn brown and nearly dry. The seeds are then easily harvested. By hand, separate them from the seed capsules they form in. Stored in a cool place in a well-sealed container, your basil seeds may be used for several years to come.
Problems
Greek basil (O. basilicum var. minimum) is a compact variety with small, fragrant leaves. It grows in an attractive globe shape.
Downy mildew diseases can be a problem for basil grown in Florida. These diseases can be hard to recognize since the most noticeable symptom, yellowing, resembles a nutrient deficiency. The tell-tale sign of a downy mildew disease is the presence of spores on undersides of leaves. The best time to scout for spores is early morning. If you still suspect downy mildew even with an absence of spores, you can place leaves upside down on a wet paper towel in a closed plastic bag. Leave the bag in a dark room for a day and then check again for spores.
These diseases are nearly impossible to prevent as the spores of this fungus are easily dispersed long distances by wind. Cultural practices that minimize leaf wetness and reduce humidity can be used to discourage fungal growth. Planting basil in an area where it receives lots of sunlight and has good air movement can help, as can using drip irrigation as opposed to overhead watering.
If downy mildew diseases are a persistent problem year after year in your herb garden, consider growing a variety of basil less susceptible to the disease. Unfortunately, all sweet varieties are very susceptible to downy mildew. Red types, Thai basil, lemon basil, lime basil, and other spicy basils have been found to be less susceptible.
For more information on growing basil and other herbs, contact your county Extension office.