UC Master Gardeners, Santa Clara County, CA
University of California
UC Master Gardeners, Santa Clara County, CA

Basil

Garden Help > Herbs

Basil (Ocimum basilicum) is a warm weather annual herb grown for both its leaves and seeds. There are many varieties of basil including Sweet, Thai, Lemon, Genovese/Italian, Purple Leaf, and Tulsi or Holy Basil. Growing techniques are common for most, although African Blue Basil is grown as a tender perennial and can be overwintered with care.

How to grow

  • Type: Summer annual
  • Light: Full sun; late afternoon shade is okay
  • Soil: Well amended soil, good drainage
  • Water: Needs regular watering, likes moist soil. Mulch soil to retain moisture
  • Size: 8–24" high x 8–12" wide, depending on variety

When to plant/propagate

Basil leaves are tender and are damaged by temperatures below 40°F. Wait until weather is thoroughly warm before planting outdoors.

  • From seed: Sow seeds indoors six weeks prior to transplant, March–May. Not usually seeded directly in the garden.
  • Transplants: Plant seedlings April-June when soil is well warmed and danger of frost is past.
  • Cuttings: African Blue Basil is often grown from cuttings taken in the late summer and overwintered in a warm location.

Harvesting

  • For most tender leaves, harvest frequently to encourage new growth and to prevent flowers from developing. Pinch off any flowers that do develop.
  • For seeds, allow flowers to develop.
  • Many beneficial insects appreciate basil flowers, so consider allowing some plants to flower.

Indoors

  • Basil can be grown as an indoor plant in a south-facing window with a minimum of 6 hours of sunlight or fluorescent lights 6 inches above the plants for 14 to 16 hours a day.
  • Harvesting can begin in about 4-5 weeks.

Common pests & diseases

More information

Recommended Varieties for Santa Clara County*

See our list of Spring Garden Market Herbs for varieties that we have found perform well here. 

*Many other varieties may also do well here in Santa Clara County. This list is based on UC Master Gardener trials, taste tests, and feedback from local growers.

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