Photo by Terry Wild Stock
From pizza to pesto, basil graces the pans and palates of foodies worldwide. But, are you aware that various cultivars of this attractive, versatile herb possess unique flavors and medicinal qualities? Believed to have been originally cultivated in ancient Greece, basil was one of the valuable commodities sought by European imperialists in 16th century India. Beyond Western culinary desires, India still regards holy basil (Ocimum sanctum), or tulsi, as sacred to the Hindu religion, and for good reason: The health benefits of this herbal adaptogen are seemingly endless. Depending on the cultivar, basil, at its best, repels mosquitoes, reduces inflammation, and may prevent certain cancers with its rich antioxidants. Whatever cultivar you choose to grow, if you provide your basil with the optimum conditions for growing, and watch for the most common diseases, you’ll reap a heavenly harvest to punctuate some delightful recipes.
Basil cultivars to try
Sweet basil (Ocimum basilicum): This common, smooth-leafed cultivar, sometimes called “bush basil” or “Genovese basil,” lends itself to pesto and other culinary delights, from salads to pizza. As a close mint relative, sweet basil eases digestion. In addition, like all basil cultivars, it’s antibacterial and antifungal, and its oil both repels insects and soothes insect bites. Aromatherapy characterizes the scent as energizing and effective in reducing headaches. The Greek Orthodox Church holds it sacred, and uses basil-infused holy water.
Sweet basil is most popularly used for cooking and pesto making.
Photo by Terry Wild Stock
Holy basil (Ocimum sanctum): Sacred to Hinduism, “the queen of herbs” is considered the spiritual manifestation of the goddess, Tulsi. This powerful antioxidant, antimicrobial, and anti-inflammatory cultivar grows purple-tinged green leaves, most commonly ingested as tea. It’s used in Ayurvedic and medicinal practices to treat afflictions, ranging from depression to wound-healing, and generally protects the body from toxins, including the possible prevention of some cancers. It’s also an adaptogen, which means it supports the body’s ability to deal with different types of stress, helping existing body systems to function optimally.
Holy Basil is most often consumed as tea a variety of maladies, and offers a peppery flavor.
Photo by Getty Images/Manoranjan Mishra
Clove basil (Ocimum gratissimum): The delicious, clove-flavored leaves are used in cooking and for tea. In parts of the world where pharmaceuticals are largely unavailable, clove basil is the most widely used plant to reduce blood sugar in patients with Type 1 diabetes.
Clove basil has a refreshing, clove-like flavor for cooking.
Photo by Flickr/Felippe Frigo
Thai basil (Ocimum bacilicum var. thyrsiflora): Used ornamentally and in Thai cooking, this licorice-flavored basil retains its flavor well at high cooking temperatures. ‘Siam Queen’ is a popular cultivar of Thai basil.
Licorice-flavored Thai basil retains flavor well when cooked at high temperatures.
Photo by Getty Images/PamelaJoeMcFarlane
‘Spicy Globe’ basil (Ocimum basilicum var. minimum): Thought to have originated in India, the word “globe” in the name references the plant’s compact, mounded growth habit, which makes it ideal for container planting. The leaves are small but highly fragrant; ‘Spicy Globe’ has a more peppery flavor.
As the name implies, 'Spicy Globe' basil has a spicy flavor.
Photo by Adobe Stock/eqroy
Lemon basil (Ocimum x citriodorum): As the name suggests, this small-leafed sweet basil cultivar possesses a strong lemon flavor. It attracts bees and butterflies, and repels mites! It’s a hybrid cultivar of O. basilicum and O. americanum — a match made in heaven.
Lemon basil attracts pollinators and adds citrus flavor to basil dishes.
Photo by Getty Images/Alexey Filatov
Sowing and Growing
Basil transplants well, so start seeds indoors 6 to 8 weeks prior to transplant, if desired. Be sure to use a grow light and a heat mat for best germination. As soon as the soil is warm enough — between 60 and 70 degrees Fahrenheit — transplant or direct-sow basil in-ground or in containers. For in-ground planting, amend the soil with compost and good drainage; for containers, use a quality soilless potting mix that includes a small amount of compost.
Basil prefers full sun, but will accept a range of full sun to light shade. Bear in mind that too much heat may scorch the leaves, so be mindful of temperature changes; basil may bolt and go to seed in hot, dry weather. To prevent this, provide some shade during stressful conditions, and water your basil plants consistently and evenly.
Photo by Terry Wild Stock
If you’ve added compost to your soil when potting in containers or sowing directly in the garden, it’s usually not necessary to add other fertilizer throughout the growing season for most basil. If basil grows as a perennial where you live, amend the soil once every spring by side-dressing plants with compost in a 1/2-inch layer.
Aphids and fungus gnats may invade your basil. Remove aphids from leaves and stems using your gloved fingers or a damp, soft cloth. Fungus gnats may be an issue when bringing plants indoors to overwinter. Allow the soil to dry out between watering, and employ sticky tape traps to capture gnats and other pests. Slugs also love to dine on basil; to deter them, use the usual remedies of beer traps, copper wire, or mesh.
Harvesting and Preserving
Though it displays pretty flowers, harvest basil before the plants bloom, if possible; the leaves will taste more robust. Remove the flowers as they bud to prolong the length of harvest time. However, if you want basil seed, leave a few flowers intact. It also doesn’t hurt to save a few flowers for pollinator insects. Harvest anywhere from 1/3 to 1/2 of the leaves at a time from individual plants, and keep harvesting as the plant grows; it’ll perform better if you do.
For the best flavor, take basil cuttings before blossoms appear.
Photo by GettyImages/LiudmylaSupynska
Nothing beats the flavor of fresh basil, but if you have too much, you can dry it for later use. Some gardeners also freeze leaves in ice cube trays. Be sure to first chop the basil leaves, and freeze them in water, or it’ll result in mushy, blackened leaves. Refrigeration for any length of time may also cause deterioration.
Propagating Basil’s Blessings
Although it’s a perennial in warmer growing zones, basil won’t overwinter in cold climates; frost will easily damage it. Bring your plants indoors for a sustained harvest, and remember to keep them away from cold drafts in winter. The heat from radiators can also be damaging. Use a full-spectrum grow light if sunlight is especially limited. Basil performs well in closed tabletop-style garden systems, another option for the small-space or kitchen herb gardener.
As a member of the mint family, Lamiaceae, some cultivars, such as sweet basil, may spread by reseeding. You can also propagate basil by taking cuttings. Carefully cut or pinch off a 4-inch stem above a node, and strip off the lower sets of leaves, as well as any flowers or flower buds. You can place the stem in water; roots will quickly form, and you can move it into soil. Don’t forget to harvest the seeds to save for future growing seasons and to share with your fellow gardeners!
A wide range of bacterial and fungal diseases threaten basil. Knowing what symptoms to watch for and how to treat them will help boost the harvest potential of those fragrant, delicious leaves!
Cercospora leaf spot, caused by the bacterium Cercospora ocimicola, creates round or irregularly shaped spots on both mature and newly emerged leaves. When infected, the spots will be dark green to brown with lighter centers. Poor watering practices usually initiate Cercospora leaf spot, so water from the base of the plant instead of overhead to combat it. Remove infected leaves, and wash your hands after handling diseased plants so the fungus doesn’t spread.
Cercospora leaf spot thrives on wet leaves.
Photo by Flickr/Scott Nelson
Fusarium wilt, caused by Fusarium oxysporum f. sp. Basilicum, promotes a condition called “damping off,” which will kill new seedlings as they emerge. If the seedlings do survive, F. oxysporum may also cause chlorosis (yellowing) and wilting of mature leaves. Occasionally, affected plants will appear stunted. Warm and wet conditions encourage Fusarium wilt. It’s also best to maintain a diligent crop rotation schedule and not plant basil in the same location more than two years in a row, because cold weather won’t kill the previous year’s spores. In addition, all leaf litter should be removed from the surface of the soil to discourage the presence of spores.
Photo by Nigel Cattlin / FLPA / Minden Pictures
Root rot, a fungal disease caused by Rhizoctonia solani or Pythium spp., occurs at the base of the plant, and can be prevented with good air circulation and low humidity. You’ll see that both the brown, soft roots and the corresponding portion of the stem located at the surface of the soil have water damage. Root rot in seedlings looks lot like damping off; young plants may suddenly keel over and die. Use sterilized soil and containers to help prevent root rot in basil, and never let plants sit in standing water.
Gray mold, caused by the fungus Botrytis cinerea, afflicts mostly container-grown plants. If left unchecked, basil seedlings will die. The fungus responsible will cause foliage to exhibit fuzzy gray or brown growths, and also appears on the surface of the soil, especially near the base of the plant. Plants will lose their leaves in rapid succession, and the stems may also become infected. Prolonged wet conditions will promote gray mold. In a greenhouse or home settings, discourage mold with proper watering, sufficient air circulation, and prompt removal of dead leaves.
Downy mildew (Peronospora belbahrii), one of the largest threats to basil crops at present, has only recently been found in North America. Often initially mistaken for a nutrient deficiency, downy mildew will at first cause pale yellow or green bands to appear on the uppermost side of the leaves, primarily near the veins, followed by fuzzy, dark, gray-purple spore growth on the underside of the leaves. The spores may be transmitted by wind, and can be easily transferred to healthy leaves through rain water or supplemental irrigation. As with most of the other basil diseases, high humidity, cool temperatures, and poor air circulation around crowded plants complete the disease cycle and exacerbate the spread of downy mildew.
Downy mildew spores can easily spread to nearby basil leaves.
Photo by Wikimedia Commons/Forest & Kim Starr
Cheddar Basil Biscuits
Photo by Adobe Stock/Alferova Evgeniya (Geshas)
Yield: 12 biscuits.
- 2 cups all-purpose flour
- 1/2 cup whole wheat flour
- 1/4 cup shredded cheddar cheese
- 2 tablespoons fresh, minced basil leaves
- 1-1/2 teaspoons baking powder
- 1/4 teaspoon salt
- Pinch of pepper
- 1 cup buttermilk
- 3 tablespoons sunflower or safflower oil
- Preheat oven to 400 degrees Fahrenheit.
- In a large bowl, combine flours, cheese, basil leaves, baking powder, salt, and pepper.
- Add buttermilk and oil, and mix until a soft dough forms.
- Roll dough out onto a floured board to 1/2 inch thickness.
- Cut rounds from the dough using a floured biscuit cutter.
- Place the rounds on an ungreased baking sheet, and bake for 15 minutes, or until lightly browned.
Note: To make this recipe gluten-free, substitute 2-1/2 cups millet or sorghum flour for the all-purpose and whole wheat flours.
Sheryl Normandeau is a Master Gardener and writer from Calgary, Alberta. She grows mostly vegetables, but also plants perennial flowers, and always has a few projects in the works. Read more about her pursuits on her blog, Flowery Prose.