Basil is easy to grow in warm sunny conditions. It is a great addition to most vegetable, fish, poultry dishes, and summer salads. And, of course, basil is the key ingredient of pesto.
- Sow basil directly in the garden or set out transplants after all danger of frost has passed in spring.
- Start basil indoors as early as 6 weeks before the last frost for planting out after the weather has warmed—3 or more weeks after the last frost.
Where to Plant Basil
- Plant basil in full sun, 6 to 8 hours of sun each day. Basil can tolerate light shade.
- Grow basil in fertile, well-drained soil. Sandy loam is ideal for growing basil, but basil will grow in poor soil as long as it is well-drained.
- A raised or mounded bed is a good spot to grow basil.
- Soil too rich in organic matter will result in lush foliage but low oil content which can affect basil’s flavor and strength of fragrance.
- Basil prefers a soil pH of 5.5 to 7.5.
- Basil can be grown indoors when outdoor temperatures are too chilly. Grow basil in a sunny window.
Basil Planting Time
- Sow basil seed directly in the garden or set out transplants no sooner than 2 to 4 weeks after the last frost in spring.
- A soil temperature of 70°F is optimal for growing basil. Air temperatures in the 80s are ideal. Basil is easily damaged by chilly weather and will be killed by frost. Nighttime temperatures in the 50°sF will cause basil leaves to turn dark or black.
- Start basil indoors as early as 6 weeks before the last frost for transplanting out after the weather has warmed.
Planting and Spacing Basil
- Sow basil seed ¼ inch deep; thin successful plants 12 to 16 inches apart or more depending on the variety. Most varieties grow 24 inches tall and 12 to 18 inches wide.
- Basil seed will germinate in about 5 days at 70°F. Purple leaf varieties need slightly warmer soil temperatures to germinate.
- Basil can be started from cuttings rooted in water or damp vermiculite.
- Grow one basil plant per household. Plant 6 to 12 plants if you make a lot of pesto.
- Make successive sowings every 2 to 3 weeks to ensure a steady supply through the season.
Growing Basil in Containers
- Basil is a good container plant.
- Plant basil in a pot with at least 6 inches wide and deep for best growth; larger is better.
- Basil grows easily in a sunny window.
- Grow basil indoors in winter from summer cuttings or seed.
- Small-leaved cultivars are a good choice for indoor growing.
Watering and Feeding Basil
- Basil prefers moist but not wet soil. Leaves will wilt when basil needs water.
- Mulch established plants to conserve soil moisture in summer.
- Foliar feed plants with a spray of compost tea or liquid seaweed extract twice during the growing season.
Companion Plants for Basil
- Plant basil near tomatoes and peppers to enhance their growth. The aroma of basil will repel many garden pest insects.
Caring for Basil
- Do not allow plants to get tall and leggy. Keep basil pinched back for full growth.
- Pinch out terminal shoots every 2 or 3 weeks. This will encourage branching and more leaves for harvest.
- Pinch out flowers as they form. Flowering will slow leaf growth.
- Mulch around basil to suppress weeds and slow soil moisture evaporation in hot weather. Mulch with aged compost or chopped dry leaves. Keep mulch back from stems to avoid rot.
- Tall cultivars may need staking.
- Do not prune or cut the woody part of the stem; prune only herbaceous growth.
- If frost is forecast, harvest the whole plant. Basil will not survive a frost.
- Snails and slugs may attack basil; handpick them and destroy.
- Aphids may attack leaves; knock them off the plant with a strong blast of water.
- Damping-off and fusarium wilt are two fungal diseases that can attack basil. Fusarium wilt and damping off will cause plants to collapse and die in a day or two.
- To prevent and control fungal diseases, make sure the soil is well drained and keep leaves dry.
- Remove and destroy infected plants.
- Avoid planting basil in the same spot more than once every four years.
- Plant fusarium tolerant varieties such as ‘Aroma’.
- Basil is ready for harvest 50 to 60 days after planting.
- Harvest leaves in the morning when they are most flavorful.
- Pinch off leaves as you need them; regular harvest will keep plants growing strong and prevent flowering.
- When a branch has 6 to 8 leaves, harvest all but the first set of leaves. This will prompt new growth.
- Avoid bruising or crushing leaves at harvest.
- Harvest the entire plant before the first frost.
Storing and Preserving Basil
- Wash and pat dry fresh basil leaves or dry leaves in a lettuce spinner.
- Fresh basil stores best at 40°F; colder temperatures will turn leaves black.
- Quick-freeze leaves to preserve flavor. Place leaves whole or chopped in airtight bags or containers and put them in the freezer. You can freeze basil leaves mixed with olive oil; use 3 cups of packed leaves for ½ cup of olive oil.
- To preserve basil in vinegar, add 1 cup of packed fresh leaves to 1 quart of vinegar.
- Basil leaves can be dried. Set leaves in a well-ventilated spot out of direct sunlight; leaves will dry in 3 to 4 days. Some flavor will be lost.
- Store crushed dry leaves in an airtight container.
Pesto making tips at How to Make Pesto.
Basil Varieties to Grow
- Sweet basil (Ocimum basilicum): most commonly grown; 24 inches tall, leaves are bright green, 2 to 3 inches long. Sweet basil is most often used for pesto. Grow Genovese types including ‘Sweet Basil’, ‘Genoa’, ‘Genovese’, ‘Aroma 1’, ‘Aroma 2’, and ‘Nufar’.
- Lemon basil ( b. crispum): good indoor grower; crinkled bright green leaves.
- Cinnamon basil ( b. Cinnamon): also known as Mexican spice basil, has a spicy, fragrant aroma and flavor.
- Purple basil ( b. ‘Dark Opal’): reddish purple leaves used often in Asian cooking. Other purple varieties include ‘Purple Ruffles’, ‘Red Lettuce Leaved’, ‘Red Osmin’, ‘Red Rubin’, ‘Rubra’.
- Thai basil (b. var. thyrsiflora) has a sweet licorice flavor.
- Miniature basil ( b. ‘Minimum’)” short, compact sweet basil.
- Tree basil ( gratissimum): grows to 6 feet tall; use as other basils.
- Camphor basil ( kilimandscharicum): strong camphor fragrance.
- Tulsi or sacred basil ( sanctum): strong clove aroma; use fresh not for cooking.
- Large leaf varieties: ‘Napolitano’, ‘Large Green’, ‘Mammoth Sweet’.
- Compact varieties: ‘Finissimo Verde a Palla’, ‘Greek’, ‘Spicy Globe’, ‘Magical Michael’, and ‘Marseillais Dwarf’.
- Basil is a subtropical perennial commonly grown as a warm-season annual.
- Basil has square stems and oppositely arranged leaves. Leaves are lightly toothed, pointed, and oval. Leaves can be bright green or purple-red.
- Spikes of small whitish or lavender flowers appear in mid to late summer.
- Use: kitchen flavoring, attract bees, insect repellent, medicine, perfume.
- Botanical name: Ocimum basilicum, Ocimum crispum, Ocimum minimum
- Origin: India, Central America