Mammoth Basil

Family: Lamiaceae Herb

Planting Schedule

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Mammoth Basil opens with an intoxicating, cool-mint brightness and a rich, classic basil perfume that lingers on the fingertips—then delivers leaves of truly generous scale.

The foliage is tender and velvety, with broad, Italian-style blades that hold their shape and color through warm weather, making it a standout for bold, aromatic use. Grow Mammoth Basil for fresh bouquets of flavor, vibrant pesto-style sauces, and fragrant finishing handfuls that perfume the garden all season long.

Light: Full SunMaturity: 60 DaysHabit: Upright

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Mammoth Basil Planting Dates by USDA Zone

Estimated US hardiness-zone windows for sow, transplant, and harvest. Enter a US ZIP above for exact local dates, or open a zone below.

Zone	Start Indoors	Sow / Transplant	Harvest
Zone 1a	May 18th	Aug 3rd	Oct 2nd – Jul 15th
Zone 1b	May 4th	Jul 20th	Sep 18th – Aug 1st
Zone 2a	Apr 27th	Jul 13th	Sep 11th – Aug 29th
Zone 2b	Apr 17th	Jul 3rd	Sep 1st – Aug 25th
Zone 3a	Apr 17th	Jul 3rd	Sep 1st – Sep 1st
Zone 3b	Apr 21st	Jul 7th	Sep 5th – Sep 21st
Zone 4a	Apr 17th	Jul 3rd	Sep 1st – Sep 24th
Zone 4b	Apr 15th	Jul 1st	Aug 30th – Sep 27th
Zone 5a	Apr 10th	Jun 26th	Aug 25th – Sep 30th
Zone 5b	Apr 6th	Jun 22nd	Aug 21st – Oct 5th
Zone 6a	Apr 3rd	Jun 19th	Aug 18th – Oct 10th
Zone 6b	Mar 28th	Jun 13th	Aug 12th – Oct 16th
Zone 7a	Mar 23rd	Jun 8th	Aug 7th – Oct 20th
Zone 7b	Mar 13th	May 29th	Jul 28th – Oct 28th
Zone 8a	Mar 4th	May 20th	Jul 19th – Nov 5th
Zone 8b	Feb 23rd	May 11th	Jul 10th – Nov 12th
Zone 9a	Feb 6th	Apr 24th	Jun 23rd – Nov 26th
Zone 9b	Jan 12th	Mar 30th	May 29th – Dec 9th
Zone 10a	Continuous Production
Zone 10b	Continuous Production
Zone 11a	Continuous Production
Zone 11b	Continuous Production
Zone 12a	Continuous Production
Zone 12b	Continuous Production
Zone 13a	Continuous Production
Zone 13b	Continuous Production

Crop Details

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

Culinary Notes

Chef's Note

Mammoth Basil throws an unmistakably cool-minty first note before the classic basil perfume settles in, so it shines when you keep it fragrant—tear it in at the end or blend it just enough for a green, glossy pesto. The oversized, velvety leaves hold their shape, making them ideal for wrapping and finishing rather than turning mushy under heat.

Best Uses

pesto that stays bright and green (blend fast, don’t overprocess)
tear-and-finish salads, grilled bread, and hot pasta right off the heat
aromatic chiffonade for soups and broths where the fragrance matters
big-leaf wraps for finishing proteins and vegetables with minimal cooking

Flavor Profile

cool-mint brightness rich classic basil perfume tender, velvety leaves with gentle snap herbaceous, aromatic finish

Kitchen Pairings

garlic olive oil Parmesan lemon mozzarella chicken

Frequently Asked Questions

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

Basil commonly suffers from downy mildew (often showing yellow patches on the upper leaves with fuzzy gray-purple growth on the underside), especially in cool, humid weather. Remove and discard infected leaves, increase airflow around plants, and water at the soil line to keep foliage dry. If the problem keeps spreading, start fresh from healthy plants because basil mildew can quickly take over dense leaf growth.

How often should I water Ocimum basilicum during the main growing phase?

During active growth (roughly weeks 3–8), water whenever the top 1 inch of soil feels dry, then soak thoroughly until water drains. Aim for consistently moist soil—not soggy—because Ocimum basilicum develops root stress and disease faster in waterlogged beds. In full sun, this often means watering about 1–2 times per week depending on your heat and soil type.

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

Harvest when plants are about 8–10 inches tall and have developed several pairs of mature leaves, typically around 60 days from sowing under good conditions. For best regrowth, pinch or cut just above a leaf pair (don’t harvest more than about one-third of the plant at once). If flower buds appear, begin harvesting more frequently to slow bolting and keep leaves tender.