Dark Opal Basil leaves on a white background.
Three colorful glass bottles filled with the beautiful leaves of Dark Purple Opal Basil.
Several Dark Purple Opal Basil leaves on a white background.
Dark Purple Opal Basil with blooming flowers growing in the gardens at Baker Creek.
A gardener holding a freshly picked bouquet of Dark Purple Opal Basil.
A close-up of Dark Purple Opal Basil growing in a greenhouse at Baker Creek.
Dark Opal Basil leaves on a white background.
Three colorful glass bottles filled with the beautiful leaves of Dark Purple Opal Basil.
Several Dark Purple Opal Basil leaves on a white background.
Dark Purple Opal Basil with blooming flowers growing in the gardens at Baker Creek.
A gardener holding a freshly picked bouquet of Dark Purple Opal Basil.
A close-up of Dark Purple Opal Basil growing in a greenhouse at Baker Creek.

Basil Seeds,
Dark Purple Opal

4.740 ReviewsSKU: #HB106Min. seed count: 100
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Description

(Ocimum basilicum). An extra flavorful, rich, and sweet basil with fragrant deep violet foliage brings drama and fragrance to your garden design! This variety was bred at the University of Connecticut in the 1950s, when Professor Joseph M. Lent and his colleague John Scarchuck set out to improve the existing purple basil variety, which had inconsistent color issues. A purple-splotched variety from Turkey was selected from countless samples from across the globe. The result was this deeply purple, vigorous variety, which they named Dark Opal. This exemplary basil took home a bronze medal in the 1962 All-America's Selection award.

Growing Tips: Dark Purple Opal basil thrives in warm, sunny conditions, and needs 8-12 hours of direct sunlight daily. It grows best in fertile, well-draining soil with a pH of 6.0-7.5. Keep the soil consistently moist but not waterlogged to ensure healthy growth. Regular pruning or pinching back of leaves will encourage bushier plants and prolong the harvest. Removing flower buds early helps preserve the flavor of the leaves and allows for continued growth.

Plant Details

Botanical Name
Ocimum basilicum
Life Cycle
Annual
Sun Requirement
Full sun
Days to Germinate
6–10
Days to Maturity
60–75
Planting Depth
¼ in.
Plant Spacing
8–12 in.
Ideal Temperature
70–85°F
Frost Hardy
No

When to Grow

Start seeds indoors 4-6 weeks before your area's last frost date, and transplant seedlings outdoors once nighttime temperatures stay above 50 F. Alternatively, seeds can be directly sown outdoors in warmer climates once all danger of frost has passed. Dark Purple Opal basil grows best during the warm summer months. Learn about your area's hardiness zones and first/last frost dates in our blog post 'Our Experts Answer Questions, Share Resources.'

How to Sow and Plant

Sow Dark Purple Opal basil seeds 1/4 inch deep in seed trays or directly in prepared garden beds after frost danger has passed. Maintain a soil temperature between 70 to 85°F for germination. Space plants 8 to 12 inches apart in the garden for optimal airflow and growth. If starting indoors, harden off seedlings over 7 to 10 days by gradually exposing them to outdoor conditions before transplanting.

How to Grow

Dark Purple Opal basil is a heat-loving plant that requires consistent care. Water regularly to keep the soil moist but well-draining, and apply a balanced fertilizer or compost every 2 to 4 weeks to support healthy, vibrant foliage. To prevent bolting and maintain the plant’s flavor, remove flower buds as soon as they appear. This basil also thrives as a container plant, making it a great choice for small gardens or patios. Its flowers attract pollinators like bees and butterflies, which will benefit the rest of your garden.

How to Save Seeds

  • Flower heads mature progressively from the bottom of the stem to the top.
  • When the bottom seed head starts to turn brown, the stem can be cut and allowed to dry away from direct sun in a well-ventilated area.
  • Rub dried raceme over a fine wire mesh and winnow off the chaff.
  • Place chaff in a bowl and carefully swirl contents around. Seeds will gather at the bottom of the bowl.
  • Tip the bowl so that the chaff can be discarded and blow the rest out carefully.

FAQ

Can I grow Dark Purple Opal basil indoors?

Yes, it grows well indoors if it receives at least 8 to 12 hours of sunlight or supplemental light from a grow lamp. Be sure to plant it in well-draining soil and water regularly.

How long does Dark Purple Opal basil take to mature?

It matures in about 60 to 75 days, but you can begin harvesting leaves as early as 3 to 4 weeks after germination.

How is Dark Purple Opal basil used in cooking?

Its slightly spicy flavor is excellent in salads, pestos, herbal vinegar, and as a garnish. The purple leaves also make beautiful herbal teas and infused oils.

Browse our full range of basil seeds.
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