When I think about summer gardening, sweet basil, Ocimum basilicum, is one of the first plants that comes to mind. From June through September, I keep bundles of fresh basil in containers on my kitchen counter, where its wonderful fragrance fills the air. Handy accessibility is essential, because I use these bright green leaves so often in meal preparation. Without fail, I also grow basil in strategic locations in my outdoor edible garden, within easy reach of my fingertips.
As a culinary and medicinal herb, basil has been cultivated for more than 5,000 years. This attractive plant, native to Asia and Africa, is a member of the Lamiaceae (mint) family. Its shiny, paired (opposite), oval-shaped leaves with pointed ends branch directly from a central stem. Most basil varieties have small white flowers, but a few can boast lovely purple blossoms. A thick taproot beneath the soil surface holds the plant upright. Regarding basil’s piquant taste and savory aroma, several natural compounds (oils) with names you probably never heard of – estragole, linalool, and eugenol – are the culprits.
Types of Basil
There are ~35 different types of basil and more than 160 cultivars. This article focuses on those that are well-known and widely-used in our region. If you want to explore new basil varieties, you can find most of these online or in mail-order seed catalogs, such as Park Seed, Burpee, or Johnny’s Selected Seeds.
Genovese: This traditional Italian basil is frequently used in tomato sauces or added to fresh salads. Its distinctive anise flavor and sweet clove-like smell make this basil a popular choice for many recipes. You may also want to try Red Genovese, which has dark purple leaves and rich taste.
Napoletano: This basil is a bit spicy, which makes it ideal for flavorful pesto, especially because it produces lots of large leaves for harvesting.
Siam Queen: This is one of several Thai basils with intense licorice flavor and notable aroma. Due to the purple stems and unique shape (like a sphere), this variety is often used as an ornamental plant.
Cinnamon: This Thai basil offers a delightful cinnamon taste, and it’s scrumptious when added to baked goods. This variety, sometimes called Mexican spice basil, has deep purple stems with narrow, dark green leaves.
Lemon or Mrs. Burns Lemon Basil: Noted for its tangy lemon flavor, this variety is a great addition to soups, stews, and curry dishes. It’s often used in Indonesian cooking.
Greek Dwarf: This compact plant with tiny leaves grows in a globe-like shape. It’s an excellent choice for container gardens, and the strong, spicy flavor makes it a perfect choice for sauces, soups, and salad dressings.
Dark Opal: This beautiful basil with showy purple leaves and deep pink flowers is favored for colorful pots and pollinator gardens. It has an unusual anise taste with a slight hint of ginger.
Cultivation
I think of basil as a “user-friendly” plant. Basil is fairly easy to cultivate (seeds or young plants), and given appropriate conditions, it will be consistently productive during the summer growing season. Basil is a warm-season crop, so wait until temperatures are consistently above 70° F during the day and above 50° F at night to consider outdoor planting. Basil is highly sensitive to frost, which means you should hold off on planting this in the garden until two weeks after the last frost date (between April 15-25) for our hardiness zone (7a for Albemarle County). Since you can never be certain when our area is finally beyond chilly nights, I recommend waiting until the second or third week of May to sow seeds or plant basil outdoors.
To thrive, this delightful culinary herb needs fertile, well-drained soil with a pH of 6-7. Be sure that your basil plants get plenty of sunlight (6-8 hours), but if your site allows for a couple hours of late afternoon shade, basil will appreciate that. Rather than planting basil in straight rows, try “interplanting,” or placing individual basil plants in-between other crops in your edible garden. Why? Due to their chemical composition, basil plants may repel some insect pests that tend to wreak havoc in outside beds, such as aphids, mites, and tomato hornworms. I tried this last year, strategically planting selected basil varieties near different kinds of tomato plants in my own garden. Results indicated that this method works. I didn’t find a single hornworm in 2021, and after one minor aphid attack, I was able to get rid of the offenders and keep them away for the rest of the growing season. To learn more, read “Plant Partnerships in Your Garden” (Garden Shed, May 2021).
Another benefit? Deer don’t like the strong smell of basil. Try planting it near the edges and corners of your garden to discourage deer browsing.
Potential Problems
Like most outdoor plants, basil is subject to certain infectious diseases. Downy mildew, which lives in soil and plant debris, is one of the most destructive. Be on the lookout for yellowing leaves with fuzzy undersides. Humid conditions encourage the reproductive sporangia to spread, so make sure basil plants have sufficient air circulation. Fusarium wilt is a fungal, soil-borne pathogen that causes stunted growth. Watch for sudden leaf drop and brown streaks on basil stems. Bacterial leaf spot is another disease that affects basil. It spreads in the soil and leads to angular spots, brown or black, on leaves. Careful observation and good sanitation practices in the edible garden, such as regular weeding, removing unhealthy stems and leaves, and cleaning up dead plant material, are the best preventive measures you can take to avoid these problems.
Harvesting Basil
Once well-established, basil plants are quite beautiful. Remember to “pinch” stem tips regularly to encourage bushier growth. Use clean, sharp scissors and cut just above a pair of leaves. Pinch away freely, as this herb will respond with increased, vigorous growth. In the summer, I make it part of my daily morning routine to step into the garden and pinch basil, enjoying the wonderful aroma as I go. Plus, you will enjoy more flavorful basil if you pinch stems early in the day, just after the dew dries. For best taste, be sure to pinch stems before the flowers appear.
Learn more about growing, harvesting, and preserving herbs in the Garden Shed in Pat Chadwick’s article (March 2021) and VCE publication 426-420 titled “Herb Culture and Use.”
Storage and Use
For use in food preparation, fresh basil is best. You can dry basil leaves (keep them whole), but the flavor of dried basil is much less pungent. To dry whole leaves, place them on a drying screen and later put them into an air-tight container for storage. Avoid crushing the dried leaves until just before use. Alternatively, you can put fresh basil leaves into ice cube trays, add a little water, and freeze them. Once frozen, transfer the basil to sealed containers for freezer storage. Use “basil ice cubes” when making soups, sauces, and stews.
To jazz up your daily food intake, consider adding this culinary herb to various dishes. You can explore many mouth-watering recipes available through the Herb Society of America. Here’s a glimpse of what they offer: basil oregano pesto, basil nasturtium salad, basil-blueberry muffins, lemon basil snap beans, and basil cinnamon ice cream. I’m eager to jump-start the growing season by expanding my repertoire of recipes. Hope you are, too!
References in Print
“Flavorful Basils” by Sue Guetz. The American Gardener, July/August 2021 issue.
Online Resources
“Basil.” Cornell University, Botanic Gardens, reference tool with links.
“Basil.” Herb society of America, informative articles about different types of basil.
“Basil, A Great Culinary Herb.” NC State Cooperative Extension, article by Minda Daughtry.
“Basil, A Summer Favorite.” Penn State Extension, illustrated article about basil.
“Basil Diseases: Various Pests.” Cornell U Plant Disease Diagnostic Clinic, descriptive article.
“Basil Downy Mildew.” Cornell U Department of Agriculture and Life Sciences, informative article with photos.
“Herb Culture and Use.” Virginia Cooperative Extension Publication 426-420 by Shawn Appling and Joyce Latimer.
“How to Grow, Harvest, and Preserve Culinary Herbs.” Piedmont Master Gardeners, Garden Shed article, March 2021.
“Ocimum basilicum.” Missouri Botanical Garden, article on basil.
“Ocimum basilicum.” NC State Extension Plant Toolbox, article and video about basil.
“Plant Partnerships in Your Garden.” Garden Shed article about beneficial plant partners.
“Virginia’s Home Garden Vegetable Planting Guide.” Virginia Cooperative Extension, hardiness zone map and details.
