SproutSmart
SproutSmart Intelligent Garden Sowing

Dark Opal

Family: Lamiaceae Herb

Planting Schedule

Add Dark Opal to your garden to build a schedule and get reminders.

Sink your senses into Dark Opal’s velvety, deep-plum leaves—an aromatic purple basil that perfumes the air with a rich, sweet-herbal fragrance.

The foliage is tender and lush, with a softly serrated, slightly cupped texture that looks as sumptuous as it smells. Grow it for standout fresh garnishing, vibrant flavor in sauces and finishing swirls, and striking color that holds its beauty when dried or lightly roasted for bold, fragrant impact.

Light: Full SunMaturity: 60 DaysHabit: Upright

Botanical illustration of Dark Opal

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

Crop Dates

MilestoneDate
Start IndoorsMar 14th
Last FrostApr 25th
Transplant / Sow OutdoorsJun 20th
Harvest BeginsAug 19th
Harvest EndsOct 16th

Crop Details

TraitValue
Days to Maturity60
Sun RequirementsFull SunFull sun
Growth HabitUpright
Support NeededNone
Planting DepthNormal
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 purple basil brings a richer, sweeter clove-basil aroma with a clean, peppery finish—choose it when you want basil that reads loud on the tongue. Chop it fine or stir it in off-heat so the leaves stay tender and aromatic instead of turning flat under heavy cooking.

Best Uses

  • hand-chopped finishing basil for salads and bowls where it stays green (and glossy)
  • blitzing into quick sauces and oils—add at the end to keep the perfume intact
  • lightly roasted or quick-dried topping on flatbread, rice, or roast squash for bold herbal impact
  • muddled into vinegar-based dressings for a fragrant, lightly spicy lift

Flavor Profile

sweet, clove-leaning basil aromatics slightly peppery bite in the finish tender, softly cupped leaves for easy tearing purple-leaf herbal sweetness that stays fragrant when warmed

Kitchen Pairings

garlic lemon olive oil parmesan mozzarella chicken

Frequently Asked Questions


Why are my dark opal basil leaves turning black or developing blotches, and what should I do?
Basil (Ocimum basilicum) is prone to fungal leaf spots and downy mildew, especially when foliage stays wet. Water at the soil line and space plants for airflow, then remove badly infected leaves to slow spread. If conditions are humid, start a preventive regimen with a copper-based fungicide labeled for basil and apply according to the label’s timing and intervals.
How often should I water Dark Opal basil during peak growth (after it’s established)?
During its main growth phase, keep the top 1 inch of soil lightly moist but not soggy; basil roots need steady moisture with good drainage. In typical summer conditions, that’s often about 1–2 times per week, increasing frequency if the soil dries faster under full sun and containers. Water deeply to wet the root zone, and stop once water runs out of the bottom of pots to avoid root problems.
How do I know when Dark Opal basil is ready to harvest?
Start harvesting around day 60 when plants are well-leafed and reach about 8–12 inches tall, but you can take light “leaf pinch” harvests earlier to encourage branching. Harvest in the morning by snipping above a pair of leaves so the plant can produce new shoots. If flowering starts, harvest promptly and keep picking to maintain tender leaf quality and prevent bitterness.