Basil plants are one of the most popular herbs to grow and also one of the easiest. Basil (Ocimum basilicum) is a member of the mint family. It is closely identified with Italian cooking, although it is originally from India. The extremely aromatic leaves also have a delightful variety of flavors, from the slightly lemony-mint of sweet basil to cinnamon and licorice. Leaf colors span from rich green to deep purple, with smooth or crinkled leaves. The flowers are insignificant but very popular with bees.
All types of basil grow easily in warm, sunny weather. The leaves are commonly used in cooking, but the flower buds are also edible. This fast-growing herb thrives equally well in gardens and containers. With sufficiently warm weather, new basil plants are ready for pruning (to encourage bushier growth) in about six weeks.
|Botanical Name||Ocimum basilicum|
|Plant Type||Perennial or annual herb|
|Mature Size||18 to 24 inches tall and wide|
|Sun Exposure||Full sun|
|Soil Type||Somewhat rich soil|
|Soil pH||5.1 to 8.5|
|Bloom Time||June to frost|
|Hardiness Zones||2 to 11 (perennial in zones 10 and above)|
|Native Area||Central Africa to Southeast Asia|
Basil plants can be grown as perennials in USDA hardiness zones 10 and above. For most home gardeners, it is grown a tender annual plant that lasts only until the first frost and must be replanted every season.
Basil is ready to start harvesting in about 60 to 90 days from seeding. Frequent harvesting or pinching of the leaves will keep your basil plants producing fresh leaves longer. You can pinch off individual leaves or take the tops off of a large plant if you need a large amount.
Prevent your basil from blooming for as long as possible by harvesting or pinching off the top sets of leaves as soon as the plant reaches about 6 inches in height. If the plant sets flowers, it is on its way to going to seed and will not grow bushy and fill out with a lot of tasty leaves. Once a basil plant goes to seed, the existing leaves begin to lessen in flavor, so don't be afraid to cut and use it, as soon as possible. The flowers are edible, too, so don't despair if a few plants get ahead of you.
The size of your plant will depend on the variety, the growing conditions, and how much you harvest. The Sweet Basil variety can reach 6 feet tall but typically grows to about 18 to 24 inches—or even shorter, since its height is kept in check if you're harvesting regularly and not letting the plant flower. Continually pinching and using your basil will coax it into becoming bushy, with more leaves. There are also short 6-inch dwarf varieties, which work especially well in pots.
Basil grows best in six to eight hours of full sun each day. Ample sun also means fewer disease problems and sturdier plants. This is the case except in the hottest climates, where basil does best in partial shade.
Basil does best in moist, rich, well-draining soil. It's a good idea to amend your soil with compost or other nutrient-rich mulch.
Water basil deeply on a regular basis, but be sure its soil is well-drained. Use mulch to help keep moisture in.
Temperature and Humidity
Basil is a heat lover. Don't bother planting it until the daytime temperatures remain in the 70s and night temperatures are above 50 degrees Fahrenheit. Seeds can be started indoors three to four weeks before your last spring frost date.
Basil is very sensitive to frost and will be one of the first plants to go in the fall. You can extend the season slightly by covering your plants with row covers when frost is threatened. Don't let the row cover touch the leaves. Frost on the outside of the row cover is enough to damage the tender leaves, likely turning them black.
If you live in a frost-free area, you might want to allow some basil plants to set flowers and self-seed in your garden. Not all varieties will do this successfully.
Because you will be harvesting leaves from your basil plants, you may need to fertilize them often. An all-purpose fertilizer works well and helps ensure that new leaves will grow continuously.
Varieties of Basil
Try these different kinds of basil:
- 'Genovese': This variety has larger leaves than Sweet Basil, with all the flavor.
- 'Cinnamon' or 'Mexican Spice': Enjoy the green foliage, purple flowers, and spicy, cinnamon scent.
- 'Finissimo Verde a Palla' and 'Spicy Clove': These quick-growing compact plants are great for containers and edges.
- 'Lemon': This variety gives a fresh lemony tang to pesto, but its small leaves can be harder to harvest. The cultivar 'Sweet Lemon Dani' or 'Sweet Dani' has a lemon flavor and larger leaves.
- 'Red Rubin': This variety keeps purple color throughout the season with great flavor. It is wonderful for flavoring vinegar.
Growing Basil in Containers
Basil works in almost any type of pot or container, even a kiddie pool. But there are two rules for success: keeping the soil moist and not crowding the plants. The easiest way to follow both rules is to plant in large, deep pots, which means more soil for moisture retention and more real estate for spreading out multiple plants and ensuring adequate air circulation. You can plant them as close as 6 to 8 inches apart if you desire a full look to your containers, but spacing them 12 to 18 inches apart is better for air circulation. Overcrowded plants are vulnerable to fungal problems.
To make sure your container plants are properly hydrated, check the soil daily by sticking your finger in to the second knuckle, and water when the soil feels dry at this depth. Use a quality potting soil that drains well so the roots do not sit in water. Also make sure the container has drainage holes. If the soil is not premixed with fertilizer, add some organic plant food and mix it in well when filling the pot. Thereafter, feed the plants every two weeks with diluted liquid fertilizer.
Growing Basil From Seed
Small basil plants are a staple offering at garden centers and even grocery stores, but they are almost as easy to grow from seed. Start seeds indoors four weeks before the last frost date in your area. Or, you can plant them directly in the garden two weeks after the threat of frost has passed. Set the seeds 1/4 inch deep in the soil and cover them lightly; they need some light for germination.
The plants will sprout in about 7 to 10 days. It's safe to transplant indoor seedlings to the garden when they have at least three sets of leaves.
Aphids are the biggest basil pest, especially with plants grown indoors. Beetles and slugs also can be a nuisance outdoors, creating holes in the leaves. Cover your entire plant with a soap solution of 2 teaspoons of dishwashing liquid to a full gallon of water to eradicate these pests.
Cooking With Basil
Basil can be used in cooking, generally added at the end to keep its fresh taste and color. Basil can also be used fresh in salads, on sandwiches, or even as a wrap around cheese cubes, for instance. One of the most popular culinary uses of Genovese basil is in the classic northern Italian pesto, traditionally made with fresh basil, Parmigiano Reggiano and Romano cheeses, fresh garlic, olive oil, and salt. Puree the mixture in a food processor or blender, and stir it directly into freshly cooked pasta (with a bit of pasta water to keep it slightly loose).
The Best Ways to Preserve Basil
Basil can be dried or frozen for use after harvest. Dried basil is convenient but at the cost of some flavor. Frozen basil has a stronger basil flavor than dried but at the cost of texture. Use frozen basil in cooked dishes. If you like to cook with basil and olive oil, blend fresh basil with your favorite olive oil and portion it into an ice tray for freezing. Store the frozen cubes in an airtight container.
Using Basil in Your Garden Design
Basil is traditionally planted alongside tomato plants. It's said they help each other grow, but it may just be for convenience in harvesting. However, basil does not need to remain in the vegetable or herb garden. Some of the shorter, purple varieties such as 'Spicy Globe' actually make nice edging plants in the ornamental garden, if you don't have problems with animals eating them. And any type of basil can easily be grown in containers. Give each plant at least a 12-inch pot in a sunny site and it should do very well.