Ocimum basilicum 'Dark Opal'
herbDeep purple-to-near-black basil with a slightly more intense, clove-like flavor compared to green basil. Beautiful as an edible ornamental in containers and mixed beds. Makes vivid pink basil vinegar and a striking garnish. Grows identically to Genovese basil but stands out visually in any garden.
Sun
full sun
Water
Every 3 days
Harvest
~65 days
Difficulty
easy
Lifecycle
annual
One season, then done
Spacing
8-12 in
Planting Depth
1/4 in
Soil pH
6.0-7.0
Soil Type
Rich, well-draining
Hardiness Zones
Zones 3 – 10
Grown as an annual — this range is its winter hardiness, but you can grow it for a single season in any zone.
When to Fertilize
At planting; light feed every 3 to 4 weeks
Fertilizer
Balanced fertilizer; avoid excess nitrogen which greens up the leaves
Start indoors 4 to 6 weeks before last frost. Full sun is essential to maintain the deepest purple color — shade causes the leaves to green up. Pinch tips frequently to prevent early bolting and keep plants compact and bushy. Remove flower spikes the moment they appear. Plants typically grow 18 to 24 inches tall. Like all sweet basils it can develop fusarium wilt, though purple types such as Dark Opal actually show some resistance to it; still rotate basil out of the bed each year and start with certified disease-free seed.
Start seeds indoors
Mar 4
Transplant outdoors
Apr 29
Projected first harvest
Jul 3
Good neighbors that attract beneficial insects or deter pests
Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide
Rotate planting location yearly; buy certified disease-free seed; remove wilted plants immediately
Insecticidal soap spray; water blast; introduce ladybugs
Handpick in morning; neem oil spray
Ensure good airflow; avoid wetting leaves; apply copper spray at first sign
Harvest frequently from stem tips just above a leaf node. The deepest color develops in younger leaves; older leaves at the base turn greener. Makes exceptional basil vinegar — steep a generous handful in white wine vinegar for 2 weeks for a brilliant pink-purple infusion. Use fresh in salads or as a garnish for visual impact.
Contains high levels of anthocyanins in the purple pigment (same antioxidants as in blueberries), plus vitamin K, vitamin A, manganese, and essential oils including eugenol and linalool.
For educational and informational purposes only — HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.