How to Grow Italian Large Leaf Basil

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Italian Large Leaf Basil

Ocimum basilicum var. basilicum

herb

Italian Large Leaf Basil is a culinary herb prized for its large, tender leaves and sweet, aromatic flavor. It is a tender annual that thrives in warm conditions and is essential for Italian cuisine, particularly pesto. The plant grows vigorously and produces abundant foliage throughout the growing season.

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Example Italian Large Leaf Basil timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Italian Large Leaf Basil

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Italian Large Leaf Basil

    Around May 27

    ≈ 40 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Italian Large Leaf Basil dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily minimum; 8+ hours ideal for robust growth
💧
Water: Keep soil consistently moist but not waterlogged; water when top inch of soil feels dry. Water at soil level to avoid wetting foliage, which can promote disease. More frequent watering needed in hot weather.
📏
Spacing: 12 inches
📅
Days to maturity: 40-60 days to first harvest
🌱
Planting depth: 0.25 inches (barely cover seeds); plant transplants at same depth as nursery pot

Soil

Type: Well-draining loamy soil rich in organic matter
pH: 6.0-7.0
Amendments:
Compost Aged manure Perlite for drainage Balanced organic fertilizer

Growing Zones

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Thrives in zones 5-11; grown as an annual in cooler zones, perennial in warm climates

3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b

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Growth Stages

1

Seedling

7-14 days

Tiny cotyledons emerge, followed by first true leaves. Seedlings are fragile and pale green.

Keep soil warm (70-75°F) and moist. Provide bright light to prevent leggy growth. Thin seedlings to 1-2 inches apart. Avoid overwatering.

2

Vegetative Growth

20-30 days

Plant develops multiple sets of true leaves and begins to establish a bushy form. Leaves are small to medium-sized initially.

Pinch out the top 2-3 leaf sets when plant is 6 inches tall to encourage bushiness. Maintain consistent moisture and warmth. Begin weekly fertilizing with diluted balanced fertilizer once seedlings are established.

3

Mature Foliage Production

30-60+ days

Plant reaches 12-18 inches tall with large, abundant, aromatic leaves. Flower buds may begin to form at leaf axils.

Continue pinching off flower buds to extend the productive foliage stage and maintain leaf tenderness. Harvest regularly (at least weekly) to encourage bushier growth. Water consistently and maintain warm temperatures above 60°F.

4

Flowering

Variable; can be extended indefinitely with deadheading

Small purple, pink, or white flowers form on terminal spikes. Leaves become smaller and more strongly flavored, texture becomes tougher.

If you wish to extend leaf production, remove flower spikes immediately. If allowing flowering for seed production or ornament, reduce watering slightly and discontinue fertilizing. Flowers are edible and attractive.

5

Seed Set & End of Season

Until frost

Flowers mature into seed pods containing tiny black seeds. Plant growth slows, foliage quality declines. Plant dies back with first frost.

Allow flowers to dry on plant if collecting seed. Cut mature seed heads into paper bags to dry and collect seed. In warm climates, plants may resprout; elsewhere, plan to succession plant for continuous harvest.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Rue Sage Fennel Kohlrabi Cabbage Mustard

Common Pests

  • Hand-pick beetles in early morning; use row covers on young plants; apply neem oil if infestation is severe

  • and

    Remove hiding spots; use beer traps; scatter diatomaceous earth around base; hand-pick at night

  • Spray with water to increase humidity; apply neem oil or insecticidal soap; ensure adequate watering

  • Use yellow sticky traps; spray with neem oil or insecticidal soap; increase air circulation

  • Improve air circulation; avoid overhead watering; spray with sulfur or potassium bicarbonate; remove affected leaves

  • Water at soil level only; remove affected leaves; improve spacing for airflow; avoid handling wet plants

Uses

🍳

Pesto & Fresh Cooking

Culinary

Italian Large Leaf Basil is the classic variety for authentic Genovese pesto, Italian pasta dishes, and fresh tomato recipes. The large leaves are tender and perfect for blending into creamy sauces or tearing fresh over salads and pizza. [source]

💊

Anti-inflammatory & Digestive Aid

Medicinal

Basil contains compounds like linalool and eugenol with anti-inflammatory and antimicrobial properties. Traditional herbal medicine uses basil tea or fresh leaves to support digestion, reduce inflammation, and promote relaxation. [source]

🏠

Aromatic Freshener & Insect Repellent

Household

Fresh basil leaves and dried sprigs naturally repel certain insects like flies and mosquitoes when placed in kitchen areas. The pleasant aroma makes basil an effective natural air freshener and culinary fragrance for the home. [source]

🎨

Dried Herb & Crafts

Craft

Basil dries well and can be used in herbal blends, sachets, or as decoration in dried arrangements. Dried basil retains much of its aromatic quality and can be stored for winter culinary use. [source]

🦋

Pollinator Support

Wildlife

When allowed to flower, basil's fragrant blooms attract bees, butterflies, and other beneficial pollinators to the garden, supporting the local ecosystem. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Begin harvesting when plant is 6-8 inches tall by pinching off the top 1-2 inches. Harvest regularly (at least 2-3 times per week) to encourage bushier growth and delay flowering. Harvest in the morning after dew dries for best flavor and aroma. Remove leaves from the top down. Never remove more than one-third of the plant at once. Leaves are most tender and flavorful before flowering; once flowers form, leaves become tougher and more bitter. For pesto, harvest large quantities when plant is in peak foliage stage (before significant flowering).

Fun Facts

  • 🌱 Italian Large Leaf Basil (also called 'Genovese' basil) is believed to originate from Liguria in northern Italy and is the traditional basil of authentic pesto alla Genovese, which carries Protected Designation of Origin (PDO) status in the European Union.
  • 🌱 Basil is a member of the mint family (Lamiaceae) and is one of the most widely cultivated herbs in the world, with over 60 varieties ranging from sweet to spicy to chocolate-scented cultivars.
  • 🌱 The word 'basil' likely comes from the Greek 'basileus' meaning 'king,' earning it the title 'King of Herbs' in culinary traditions across Europe and Asia.

Gardening Terms

New to gardening? Learn about terms used in this guide:

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