Mammoth

Family: Lamiaceae Herb

Planting Schedule

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Aromas of sweet clove and fresh green tea rise the moment you brush the leaves—Mammoth Basil is a true showpiece with large, velvety foliage that feels substantial in the hand.

Expect tender, broad leaves with a smooth, slightly crinkled surface and a lush, upright growth habit that makes harvests abundant and satisfying for fresh use and bold flavoring in sauces, pesto-style blends, and fragrant garnishes.

Light: Full SunMaturity: 55 DaysHabit: Upright

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Mammoth 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	Sep 27th – Jul 15th
Zone 1b	May 4th	Jul 20th	Sep 13th – Aug 1st
Zone 2a	Apr 27th	Jul 13th	Sep 6th – Aug 29th
Zone 2b	Apr 17th	Jul 3rd	Aug 27th – Aug 25th
Zone 3a	Apr 17th	Jul 3rd	Aug 27th – Sep 1st
Zone 3b	Apr 21st	Jul 7th	Aug 31st – Sep 21st
Zone 4a	Apr 17th	Jul 3rd	Aug 27th – Sep 24th
Zone 4b	Apr 15th	Jul 1st	Aug 25th – Sep 27th
Zone 5a	Apr 10th	Jun 26th	Aug 20th – Sep 30th
Zone 5b	Apr 6th	Jun 22nd	Aug 16th – Oct 5th
Zone 6a	Apr 3rd	Jun 19th	Aug 13th – Oct 10th
Zone 6b	Mar 28th	Jun 13th	Aug 7th – Oct 16th
Zone 7a	Mar 23rd	Jun 8th	Aug 2nd – Oct 20th
Zone 7b	Mar 13th	May 29th	Jul 23rd – Oct 28th
Zone 8a	Mar 4th	May 20th	Jul 14th – Nov 5th
Zone 8b	Feb 23rd	May 11th	Jul 5th – Nov 12th
Zone 9a	Feb 6th	Apr 24th	Jun 18th – Nov 26th
Zone 9b	Jan 12th	Mar 30th	May 24th – Dec 9th
Zone 10a	—	Oct 1st	Nov 25th – Feb 28th
Zone 10b	—	Oct 1st	Nov 25th – Feb 28th
Zone 11a	—	Oct 1st	Nov 25th – Feb 28th
Zone 11b	—	Oct 1st	Nov 25th – Feb 28th
Zone 12a	—	Oct 1st	Nov 25th – Feb 28th
Zone 12b	—	Oct 1st	Nov 25th – Feb 28th
Zone 13a	—	Oct 1st	Nov 25th – Feb 28th
Zone 13b	—	Oct 1st	Nov 25th – Feb 28th

Crop Details

Trait	Value
Days to Maturity	55
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

Mammoth Basil’s large, velvety leaves carry a sweet clove and green-tea perfume that tastes most alive when handled gently—torn or blended with oil and finished off-heat. Choose it over small-leaf basils when you want aroma to dominate, not just act as background herb.

Best Uses

pesto-style blends where the big leaves stay lush and aromatic
warm herb butter—stir in off-heat so the perfume doesn’t fall flat
torn-leaf salads or tomato slices that need a sweet, fragrant lift
fragrant garnishes for soups and braises right at service

Flavor Profile

sweet clove-leaning basil aroma fresh green-tea brightness tender broad leaves with a velvety bite mellow, aromatic finish rather than peppery heat

Kitchen Pairings

lemon garlic olive oil parmesan mozzarella tomatoes

Frequently Asked Questions

What’s the most common pest or disease issue for Ocimum basilicum (Mammoth basil), and how do I fix it?

Downy mildew is a frequent problem for basil in humid weather, showing as yellow patches on top leaves with gray/purple growth underneath. Remove infected leaves immediately, improve airflow between plants, and water at the soil line early in the day so foliage stays dry. If it keeps recurring, switch to a weekly preventive spray of a labeled biofungicide (based on your local product guidance) rather than watering more heavily.

How often should I water Mammoth basil during the main growing phase?

During active leaf growth, keep soil consistently moist but not soggy—water when the top 1 inch of soil feels dry. Typically this means about 1–2 times per week outdoors, but in hot spells you may need more frequent watering to prevent leaf droop. Avoid splashing leaves, because wet foliage promotes basil diseases.

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

Start harvesting when plants are about 6–8 inches tall and have multiple mature leaf sets, roughly around 55 days for best production. Harvest by pinching or cutting above a pair of leaves to encourage branching, and take the top growth first. If the plant starts forming flower buds, harvest sooner and more often, because flowering quickly reduces leaf tenderness and flavor.