Basil Seeds - Mammoth Leaf (Ocimum basilicum)

Mammoth Leaf Basil (Ocimum basilicum) is an heirloom basil variety known for its exceptionally large, aromatic green leaves and vigorous summer growth. This hardy warm-season annual produces broad foliage that thrives in full sun and adds lush texture to containers, raised beds, and herb garden displays. Flowering spikes attract bees and beneficial pollinators, making it an attractive choice for ornamental and edible garden landscapes.

Features

• Extra-large aromatic foliage providing lush garden texture.
• Heirloom basil variety with vigorous summer growth.
• Suitable for containers, raised beds, and garden borders.
• White flowering spikes attract bees and beneficial pollinators.
• Non-GMO seed variety ideal for home herb gardens.
• Heat-tolerant warm-season annual for full sun locations.

Specifications

• Common Name: Mammoth Leaf Basil
• Scientific Name: Ocimum basilicum
• Plant Type: Annual herb
• USDA Zones: 4–11 (grown as annual)
• Leaf Type: Extra-large aromatic leaves
• Bloom Color: White
• Height: 18–30 inches
• Heirloom Status: Yes
• GMO Status: Non-GMO
• Organic: Not certified organic
• Light Requirements: Full sun
• Soil Preference: Rich, well-drained soil
• Water Needs: Moderate, avoid soggy soil
• Days to Maturity: 60–75 days
• Heat Tolerance: High once established
• Cold Tolerance: Frost sensitive
• Plant Spacing: 10–14 inches apart
• Seed Longevity: 3–5 years stored cool and dry

Planting Guide

• Start seeds indoors or sow directly outdoors after frost.
• No soaking or special treatment needed before sowing.
• Plant indoors 4–6 weeks before the final frost date.
• Outdoor planting begins when soil is warm in spring.
• Sow seeds 1/8 inch deep; lightly cover with soil.
• Germination occurs in 5–10 days in warm conditions.
• Provide full sun exposure for maximum leaf growth.
• Use well-drained soil enriched with organic matter.
• Keep soil evenly moist during germination, then water moderately.
• Pinch growing tips regularly for a fuller plant shape.
• Remove flower spikes if leafy growth is preferred.
• Avoid overwatering when grown in containers.