Grown for both culinary and ornamental uses, first discovered in the early 1800s, it is a sweet basil cultivar with deep purple glossy leaves and lilac flowers making it a beautiful ornamental plant too. Opal makes wonderful aromatic oils, vinegar, and colorful pestos.
Germination: 5-10 days
Germination Temperature: Optimum soil temperatures 65-70ºF
Seed Planting Depth: Sow on the surface and lightly cover
Starting Indoors: Start indoors 4-8 weeks before the last frost. Provide 65-70ºF soil temperatures. Transplant after the last frost, 8-12" apart.
Sowing Outdoors: After the last frost, sow a few seeds every 2-4”. Thin to the strongest seedling, 8-12" apart. Sow heavily seeded rows and use the baby greens earlier in the season. Sow again in mid-summer for later harvests.
Growth Habit: Upright, branching
Height and Width: 12-18” x 12”
Spacing: 8-12” apart
Light Needs: Full sun
Soil Needs: Fertile, moist, well-drained
Harvest: Start when the plants are 6-8”, picking leaves as needed. Harvest often to keep the plant producing new leaves. Freeze or dry to preserve
Uses: Culinary and medicinal, containers, flowers attract pollinators and beneficials
Care: Needs fertile soil, amend with compost and/or add organic fertilizer. Basil does not like to dry out, keep well watered for optimum growth, mulching will help retain moisture.
Tips: Pinch seedlings back to encourage branching and increase leaf production. Pinching off the flowers helps the plant continue producing leaves. We like to pinch off flowers on some plants and leave flowers on others for the pollinators. Flowers are also nice in mixed bouquets. Try growing basil indoors on the windowsill or under grow lights. Growing basil as a micro green is an easy way to enjoy fresh basil during the winter months.