How to Grow Opal Basil
Wikimedia Commons
Opal Basil
Ocimum basilicum 'Opal'
herbOpal basil is a stunning ornamental basil variety with deep purple, almost black foliage and delicate pink or lavender flowers. It offers the same culinary basil flavor as green varieties while adding striking visual interest to gardens and dishes. This variety is prized equally for its aesthetic appeal and its versatile use in cooking.
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Example Opal Basil timeline · Pittsburgh, PA (Zone 6b)
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Plant Opal Basil
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Opal Basil
Around Jun 26≈ 70 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Opal Basil dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-11; treated as an annual or grown indoors in cooler climates
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Seedling
2-3 weeksTiny seedlings emerge with two rounded cotyledons; first true leaves develop and show the characteristic purple coloration
Keep soil warm (70-75°F) and consistently moist. Provide bright light to prevent leggy growth. Thin to strongest seedlings if direct seeding.
Vegetative Growth
3-4 weeksPlant develops multiple sets of purple leaves on sturdy stems; foliage darkens as the plant matures
Pinch off flower buds initially to encourage bushier, leafier growth. Maintain consistent moisture and full sun exposure. Begin harvesting outer leaves once plant has 6-8 leaf sets.
Branching
3-4 weeksPlant becomes fuller with lateral branches emerging from leaf nodes; overall plant shape is compact and rounded
Continue pinching terminal buds to maximize leaf production. Fertilize lightly every 2-3 weeks with balanced fertilizer. Ensure adequate spacing for air circulation.
Flowering
4-6 weeks (continues until frost)Delicate pink or lavender flowers appear in terminal spikes above the purple foliage, creating striking ornamental displays
Allow some flowers to bloom for visual impact and pollinator attraction, but remove most flower buds to extend leaf production. Flowers are edible and attract beneficial insects.
Mature/Harvest
Until first frost (or ongoing indoors)Plant reaches full size (12-18 inches tall) with abundant purple foliage and persistent flowers; begins to slow new leaf production in late season
Continue regular harvesting to encourage productivity. As temperatures cool, reduce watering frequency. Plan for end-of-season preservation or bring indoors before first frost.
Common Pests
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Handpick in early morning; use row covers on young plants; apply neem oil if severe
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Spray with strong water jet to dislodge; apply insecticidal soap; encourage beneficial insects like ladybugs
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Use yellow sticky traps; spray undersides of leaves with neem oil; increase air circulation
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Increase humidity; spray with water mist; apply neem oil; avoid excessive nitrogen fertilizer
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Plant resistant varieties; ensure excellent drainage; remove and destroy infected plants; do not overhead water
Uses
Culinary Herb & Seasoning
CulinaryOpal basil offers the classic sweet, peppery basil flavor while adding dramatic color to dishes, garnishes, and beverages. Use fresh leaves in pasta, salads, vinegars, cocktails, and Thai cuisine, or create unique purple-hued pesto and compound butters. [source]
Herbal Infusions & Wellness
MedicinalBasil contains compounds with anti-inflammatory and antimicrobial properties. Brew fresh leaves as herbal tea to support digestion and provide antioxidant benefits. [source]
Natural Pest Control & Fragrance
HouseholdDried basil plants and sachets repel household insects naturally. Fresh basil also deters flies and mosquitoes when placed on tables or near windows. [source]
Ornamental & Floral Design
CraftOpal basil's striking purple foliage and pink flowers make it highly valued in cut flower arrangements, dried floral displays, and ornamental container gardens. [source]
Pollinator Support
WildlifeThe delicate pink flowers attract bees, butterflies, and other beneficial pollinators while providing them with nectar and supporting garden biodiversity. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Pinch or cut leaves from the top of the plant, removing no more than one-third of foliage at a time. Harvest in the morning after dew dries for best flavor. Regular harvesting encourages bushier growth and delays flowering. Continue harvesting until first frost approaches or plant begins to decline. Individual leaves can be harvested anytime, or entire stems can be cut for dried preservation.
Fun Facts
- 🌱 Opal basil's deep purple coloration comes from anthocyanin pigments, the same compounds responsible for the color in blueberries and red wine, which provide antioxidant benefits.
- 🌱 Unlike some ornamental basils that sacrifice flavor, Opal basil retains the full culinary profile of standard green basil, making it a truly dual-purpose plant.
- 🌱 The vibrant purple leaves deepen in color as the plant matures and receives more sunlight, with plants grown in shadier conditions being noticeably lighter than their sun-loving counterparts.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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