Dark Opal Basil

Family: Lamiaceae Herb

Sink your senses into Dark Opal Basil’s velvety, near-black leaves that unfurl with a cool, peppery-sweet aroma and a richly herbal depth.

The foliage is compact and lush, with a tender, succulent texture that holds its character beautifully when gathered fresh. Ideal for classic Italian-style pesto and fragrant garnishes, this variety brings dramatic color and aromatic punch to salads, sauces, and quick finishing touches.

Light: Full SunMaturity: 60 DaysHabit: Upright

Botanical illustration of Dark Opal Basil

Planting schedules and alerts are optimized for Columbus (Zone 6b).

Crop Dates

Milestone	Date
Start Indoors	Mar 14th
Last Frost	Apr 25th
Transplant / Sow Outdoors	Jun 6th
Harvest Begins	Aug 5th
Harvest Ends	Oct 16th

Crop Details

Trait	Value
Days to Maturity	60
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	60
Min Night Temp (°F)	50
Harden Off (days)	10

Culinary Notes

Chef's Note

Dark Opal Basil brings a more peppery, cool-aromatic swagger than plain sweet basil, and its tender leaf mass stays intact for pesto without turning stringy or dull. Use it at the end—especially with olive oil and citrus—so that near-black, velvety aroma hits before heat flattens it.

Best Uses

classic pesto where the leaves stay lush and green-toned after pulsing
fresh torn-leaf salads and cucumber/olive oil plates that need aroma on contact
quick pan sauces and finishing oil (adds fragrance without cooking away)
garnishing soups and roasted vegetables at the end for maximum lift

Flavor Profile

cool peppery bite peppery-sweet, aromatic top notes tender succulent leaf texture deep herbal, slightly clove-like basil finish

Kitchen Pairings

Parmigiano-Reggiano Extra-virgin olive oil Garlic Lemon zest Mozzarella Pine nuts

Frequently Asked Questions

What pest or disease most often affects Ocimum basilicum (basil) and how do I fix it?

Basil commonly gets downy mildew (often starting as yellow patches on the upper leaf surface with gray-purple growth underneath). Remove affected leaves right away, improve airflow around plants, and water at the soil line (not onto leaves). If it keeps spreading, use an appropriate fungicide labeled for downy mildew on basil, and avoid re-wetting foliage for the rest of the crop cycle.

How often should I water Ocimum basilicum during peak growth, and what soil moisture should I maintain?

During the main growing phase, keep the soil consistently moist but not waterlogged—aim for lightly moist soil 1–2 inches down. Water about once every 2–4 days depending on heat, increasing frequency during hot, windy spells and reducing it if the soil stays wet. If leaves droop midday but perk up by evening, water more; if stems stay soggy or you see yellowing with mushy growth, cut back immediately.

How can I tell when Dark Opal basil (Ocimum basilicum) is ready to harvest?

Harvest when plants have reached about 6–8 inches tall and form several full sets of leaves, typically around 60 days from sowing. Take the top 2–4 inches and pinch just above a leaf pair to encourage branching, rather than cutting one large, unbranched stem. If plants begin flowering, leaves often become less tender—harvest before buds open or strip buds to keep leaf quality high.