How to Grow Purple Basil / Dark Opal Basil
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Purple Basil / Dark Opal Basil
Ocimum basilicum 'Dark Opal'
herbDark Opal basil is an ornamental culinary herb with deep purple-black foliage and pink to purple flowers. It has a slightly peppery, clove-like flavor with fruity notes, making it both visually striking and delicious. This variety is more cold-tolerant than green basil and grows as a compact, bushy plant.
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Example Purple Basil / Dark Opal Basil timeline · Pittsburgh, PA (Zone 6b)
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Plant Purple Basil / Dark 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 Purple Basil / Dark Opal Basil
Around Jun 6≈ 50 days after planting
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Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-10; can be grown as an annual in cooler zones or in containers
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Seedling
2-3 weeksSmall purple-tinged cotyledons emerge within 5-10 days. First true leaves appear serrated and deep purple-green.
Provide bright indirect light. Keep soil consistently moist. Maintain warm temperatures (70-75°F). Thin seedlings to prevent crowding.
Vegetative Growth
4-6 weeksPlant develops multiple stems with increasingly large, deeply purple oval leaves. Bushy form establishes. Foliage deepens to dark opal color.
Pinch out top 2-4 leaves frequently to promote branching and bushiness. Keep consistently watered. Feed with balanced fertilizer every 2-3 weeks.
Flowering
Begins at 6-8 weeks; ongoing if flowers are pinchedSpike-like flower buds form at stem tips with small pink or purple flowers arranged in whorls. Flowers are edible and ornamental.
Pinch off flower buds to extend leaf harvest and prevent plant from becoming woody. If allowing flowers, harvest them for culinary or ornamental use.
Mature/Harvest Ready
Continuous from week 8 onward until frostPlant reaches 12-24 inches tall with dense, bushy foliage of dark purple leaves. Full ornamental and culinary potential achieved.
Harvest regularly to encourage continued branching and prevent flowering. Remove any yellowing lower leaves. Continue regular watering and feeding.
Senescence/End of Season
Variable; frost-sensitive annualPlant slows growth in cooler temperatures or if exposed to frost. Foliage may become less vibrant; flowering increases if not deadheaded.
In frost-prone areas, harvest heavily before first frost. Can be brought indoors in containers. Compost spent plants after frost damage.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick in early morning, use row covers, apply neem oil or insecticidal soap
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Spray with strong water stream, apply insecticidal soap or neem oil, encourage beneficial insects like ladybugs
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Increase humidity by misting, spray with neem oil, use horticultural sulfur in dry conditions
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Yellow sticky traps, insecticidal soap, neem oil, reflective mulch
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Remove affected leaves, spray with neem oil or spinosad, encourage parasitic wasps
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Allow soil surface to dry slightly between waterings, use yellow sticky traps, apply diatomaceous earth
Uses
Gourmet Cooking & Garnish
CulinaryDark Opal basil adds stunning visual appeal and unique peppery-clove flavor to dishes, salads, pasta, and cocktails. Its striking purple color makes it prized for upscale plating and garnish work. [source]
Pesto & Infusions
CulinaryCreates beautiful deep purple pesto with a distinctive flavor profile. Can be used to infuse vinegars, oils, and syrups for unique culinary applications. [source]
Herbal Tea & Wellness
MedicinalPurple basil contains anthocyanins and polyphenols that support antioxidant and anti-inflammatory health benefits. Brewed as a tea or added to herbal infusions. [source]
Ornamental & Floral Design
CraftThe deep purple foliage and pink flowers make Dark Opal basil an excellent choice for ornamental borders, container gardens, and fresh or dried floral arrangements. [source]
Natural Dye & Crafts
HouseholdPurple basil leaves and flowers can be used to create natural dyes for textiles and crafts, yielding purple and mauve tones. Often dried for potpourri and craft applications. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Begin harvesting when plant has 6-8 true leaves; pinch off top 2-4 leaves at leaf nodes to encourage bushiness. Harvest regularly (every 2-3 days when growing vigorously) to extend production and prevent early flowering. Harvest in early morning after dew dries for best flavor. Can harvest up to one-third of plant at a time. Leave at least 4-6 leaves on plant for continued growth. Fresh leaves are best but can be dried or frozen for later use.
Fun Facts
- 🌱 Dark Opal basil was the first ornamental basil variety bred for commercial production in the 1950s, created by Abbe Payseur, a French horticulturist.
- 🌱 The deep purple color comes from anthocyanin pigments, the same compounds that make blueberries and red grapes beneficial—making this basil not just beautiful but nutritionally distinct from green basil.
- 🌱 In Victorian times, purple basil was valued as an edible garnish for formal dinner tables and was featured in bouquets, bridging the gap between ornamental and culinary herb traditions.
Gardening Terms
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