Fragrant basil is one of the easiest herbs to grow, but it can really thrive when you know how to plant it and what to expect. Whether you plan to liven up your spaghetti sauce, add some zing to a salad or sprinkle over garden-fresh tomatoes and mozzarella, cultivating basil can be a delicious endeavor.
Planting Basil From Seed
Basil grows from seed in as little as 3 to 4 weeks, and it isn't too challenging to coax into a full-grown plant.
Seed Sowing Depth
The key to planting basil seeds is to sow them at a very shallow depth -- 1/8-inch to no more than 1/4-inch under rich topsoil. They'll do best if direct light reaches them. You should see the basil seeds germinate in just 5 to 7 days, though some varieties like Dark Opal (purple) basil can take as long as 14 days. Make sure that the soil is well-drained, and don't overwater -- a light mist daily is enough.
When and Where to Sow Basil Seeds
Because it's so easy to grow, basil can do well whether you start it indoors and transplant it or plant it directly outdoors after the last frost. If you choose to grow basil inside, start your seeds growing about 6 to 8 weeks before you'll want to move them to an outdoor garden. Basil does best in warmer temperatures, so aim for a temperature of at least 65°F for the seeds to germinate.
Some people also grow basil indoors as part of a kitchen garden, so they always have access to fresh herbs. Basil can thrive indoors if you ensure it has sunlight and well-drained soil.
The Basics of Basil
When you think of basil, you probably first picture Italian basil with its large leaves and think of the plant's use in a variety of Italian dishes. But basil actually originated in India, and has been part of culinary traditions for thousands of years. Today, basil is available in many different varieties with different colors and tastes.
Plant Height and Width
Traditional Italian basil (Ocimum basilicum) has some of the largest and most fragrant leaves of any variety. Each plant grows to between 12 and 24 inches tall and spreads to between 12 and 15 inches wide.
Italian basil's leaves are large and shiny green. It's not unusual for a leaf to reach the size of your palm, though most are slightly smaller. Other varieties tend to have narrower and more pointed leaves, notably the flavored types like lemon basil and lime basil. Leaf color of other varieties ranges from yellowish-green to purple.
Basil is actually related to mint, so it can grow much like that plant does. While it's typically not spindly, only a few varieties of basil, like spicy globe basil, take a mounded form. Leaves often grow in groups of four to six with the smaller leaves above the larger ones.
Basil plants flower easily and the flowers should be pinched off before they appear to extend the life of your plant. Italian basil produces small white flowers that form in a spike at the center of the leaves.
Varieties of Basil
There are hundreds of basil varieties, but here are a few of the most common:
- Italian Large Leaf Basil. One of the best known types of basil, Italian is used to flavor many Italian dishes as well as those from other nations. Many people plant them with tomatoes and other vegetables to help repel pests.
- Holy Basil. Used in Hinduism, holy basil grows up to 20 inches tall with small, green leaves that smell like anise. It's more common to use the leaves in tea or potpourri than in cooking.
- Sweet Basil. Sweet basil is also popular for cooking and is a slightly smaller and less vibrantly green version of the Italian variety. It's the most common type of basil used to make pesto. The plant can grow larger than Italian basil -- up to 36 inches tall.
- Thai Basil. With its sweeter licorice flavor, Thai basil is used to flavor Thai dishes. Both leaves and the plant's tiny purple flowers are used in culinary applications but the flavor is much different from the more savory Italian or sweet basil.
- Spicy Globe Basil. This plant is generally smaller than its counterparts with tiny, spicy leaves and a stronger mounding habit than other types of basil. It may be a good choice for a kitchen garden or patio.
- Lemon Basil. Lovely lemon basil has a citrusy flavor and a higher growing habit, reaching 30 inches tall. It's excellent at repelling insects and is often used as a companion plant to keep away aphids and mites. It has a lighter green, more pointed leaf that can be used to flavor sauces, soups and teas as well as some Asian-inspired dishes.
- Lime Basil. Lime basil smells great and can be used much like lemon basil, in many dishes and for tea. It also is a good insect repellant.
- Dark Opal Basil. With dark-red to purple leaves, Dark Opal basil doesn't closely resemble its greener cousins but has a similar, savory taste. Its flowers attract butterflies and beneficial insects.
No matter which variety of basil you choose to plant, you'll be able to enjoy a pleasant smell and use the leaves to flavor your foods or make tea or potpourri.
Pests and Problems that Impact Basil
Well-cared for basil plants are relatively hardy. They are thought to have antifungal properties and may repel some insects, but unhealthy plants or those from poor-quality seed may be plagued by some garden pests and plant pathogens.
Pests that Eat Basil
- Slugs and snails. These common garden pests are happy to chew holes in the leaves of your basil plant. Protect the plants with a generous sprinkling of diatomaceous earth or your favorite non-toxic commercial slug bait.
- Japanese beetles. Another pest that likes to eat almost anything, Japanese beetles can chew holes in your basil during the summer months. Small numbers of these pests can be destroyed by shaking them off plants into soapy water or using an insecticidal soap spray.
- Aphids. You'll find tiny aphids on the underside of your basil leaves; they can also chew holes in the leaves. Insecticidal soap, neem oil or a generous application of live ladybugs -- the aphid's natural predator -- can reduce their numbers.
Diseases that Harm Basil
- Leaf spot. As the name implies, dark spots form on leaves. Caused by a bacterium that's attracted to wet, humid areas, the risk of this disease can be minimized by not overwatering or letting drops of water sit on the plant's leaves.
- Downy mildew. The plant's leaves get yellow, especially along the middle, and you may see gray fuzzy growth on the underside. Keep conditions dry and buy your seed from a reputable source to keep mildew at bay.
- Fusarium wilt. This fungal disease attacks mostly younger plants and can kill them completely. It lives in the soil and is tough to eliminate, so try another, more resistant variety of basil.
Harvesting and Storing Basil
As soon as your plant has at least six leaves, you can start to harvest from it. However, you may want to wait a bit for larger-scale harvesting until you have full stems.
Cutting off full stems right where two leaves grow will help the plant maintain a nice bushy form and not get spindly. Harvest from around the entire plant to keep it balanced and looking nice.
Once you have removed a stem with leaves, snip each leaf off and toss the stem. The leaves can be stored in a plastic bag in the refrigerator for up to two days. Some people freeze or dry the leaves to preserve them, but that can reduce the taste. Fresh leaves are best for most culinary applications.
Uses for Basil
Basil is most often used for flavoring sauces and stews. It's often added to the recipe shortly before cooking is finished to preserve as much flavor as possible; basil tends to lose its taste if overcooked.
Some types of basil are used for medicinal purposes. Oil from the leaves has an antifungal property that can be useful to treat some human diseases. Basil is most commonly used in traditional Chinese medicine or Ayervedic practices.
Basil also plays a role in some religious practices, especially holy basil that has a unique position in Hinduism. Ancient Egyptians and Greeks associated basil with safe journeys in the afterlife. In Greek Orthodox ceremonies, it is sometimes sprinkled into the holy water.