Growing Basil in the Home Garden

by Diane Keller, Fairfax Master Gardener

Basil Leaves

Basil Leaves

Basil (Ocimum basilicum), one of the most popular herbs, is easy to grow and can be used in a variety of ways. From health benefits such as immune support, antioxidants and anti-inflammatory effects, to culinary dishes and aromatherapy, basil is a very multifaceted herb. The characteristically green vibrant color and calming scent of the basil plant draws attention from gardeners, chefs and aromatherapists alike.

Basil is a member of the mint family that includes over 150 types that differ in size, color of leaves and flowers. Whether used in pesto or in salads to season and garnish, basil is a cook’s best friend. Sweet basil is available year round and is an extremely easy plant to grow both outdoors during warm weather or indoors during the wintertime.

You can start your indoor basil four to six weeks before the growing season or, if you prefer, basil can be directly sown into the ground when all chances of frost have passed. Plant the seeds about a quarter of an inch deep in soil with a pH of about 6.0 to 7.0. Basil prefers sandy loamy soil. Keep the soil around basil moist and avoid watering the leaves. Water regularly, fertilize and harvest the leaves often. After seedlings grow their first six leaves, prune or pinch above the second set of leaves. Every time a branch has six to eight leaves, repeat and prune the branches back to their first set of leaves. This pruning process keeps the plant growing strong and provides lots of fresh leaves to use throughout the summer.

When pruning, always make sure to leave at least 4 sets of true leaves for continual growth of the plant. When flowers appear on the basil plant, make sure to prune them off. If you leave the flowers on the basil, the leaves will be adversely affected and may give the leaves a more bitter taste. These flowers should not go to waste; they are edible and bring a wonderful pop of color to salads or meals when used as a garnish.

Genovese Basil

Genovese Basil

Plant basil in a spot that gets at least 6 hours of sun but also gets some shade to protect the plant from the middle of the summer heat. Make sure plants are spread far enough apart so that the plants can dry out after watering and have air circulating throughout their leaves. Basil gets along very well with other plants in your garden, such as tomatoes, asparagus and beans. It can also be companion planted with other herbs in your garden, such as dill or parsley. Basil can also be grown indoors near a sunny window during the colder months of the year. Make sure to prune the leaves as described above for the plant to continue to grow.

The most common type of culinary basil is ‘Sweet’ Basil. This is the type of basil most commonly seen in grocery stores. Another variety of basil is ‘Genovese.’ It has large leaves and is mostly used in making pesto sauces. ‘Genovese’ Basil is usually added after a dish is cooked as the leaves do not withstand high cooking temperatures. Other varieties include ‘Thai’ Basil, which has a licorice-like flavor. ‘Thai’ Basil has a purple stem with small, serrated leaves and can withstand higher cooking temperatures due to its sturdy leaves. ‘Purple Ruffles’ Basil has purple ruffly leaves and has a hint of clove when eaten. It can be used in pesto, salads and drinks. ‘Greek’ Basil has small leaves and a slight peppery taste. It can be used for pesto, salads and garnish and is very much like ‘Sweet’ Basil. ‘Lemon’ Basil has the taste of lemon with medium-sized leaves that can be used in any dish that you would normally add lemon.

Purple Ruffles Basil

Purple Ruffles Basil

Basil was once a plant that even a beginning gardener could successfully manage. This all changed in 2007 when a plant pathogen known as basil downy mildew (BDM) was first discovered. This pathogen quickly spread throughout the world destroying the global sweet basil industry. Bacterial leaf spot is now also a continuing problem with basil. Rutgers University has a $3.2 million grant to study the basic plant genetics, breeding and plant pathology of basil. Along with generating new sweet basil lines, the researchers are studying genetic markers associated with resistance genes that can help develop new and stronger disease-resistant plants and improve other traits such as leaf size, shape and aroma. At this point in time, there is not a specific basil plant that is immune to both downy mildew and bacterial leaf spot, but there are some disease-resistant types of basil.

‘Pepper’ Basil, ‘Lime’ Basil, ‘Sacred’ Basil, ‘Thai Sweet’ Basil and Rutgers DMR varieties (which include ‘Devotion,’ ‘Obsession,’ ‘Passion’ and ‘Thunderstruck’) are just a few of the basil varieties that seem to be disease resistant. It should be noted that, although today these types of basil show a resistance, current BDM-resistant sweet basils, including those developed at Rutgers, have begun to display a breakdown in resistance in the U.S. and Europe, demonstrating how BDMs (basil downy mildews) can already adapt and develop new races.

As much as gardeners love basil, so do aromatherapists. Basil is used in aromatherapy for its sweet smell and calming qualities and is also used for its medicinal properties. For example, ‘Holy’ Basil essential oil is high in the chemical components of eugenol, 1,8-cineole, estragole and bisabolene. Eugenol has shown in studies to demonstrate significant antimicrobial activity, with potential anti-inflammatory, cardiac health and analgesic benefits. ‘African’ Basil is high in the chemical constituents of estragole and camphor. Some research has shown that estragole has anti-inflammatory, antimicrobial, antioxidant, insecticidal and cholesterol lowering potential. Camphor products may help with respiratory complaints.

No matter what purpose we use basil for, this herb is versatile, multifaceted and loved by all.