How to Grow Chestnuts

Introduction to Chestnuts

Chestnuts are making a comeback! Once devastated by chestnut blight in the early 1900s, modern blight-resistant hybrids allow growers to enjoy this delicious, nutritious nut again. Chestnuts are low in fat, high in carbohydrates, and have a sweet, starchy flavor.

Types of Chestnuts

Chinese Chestnut (Castanea mollissima)

• Zones: 4-8
• Size: 40-60 ft
• Blight Resistance: Highly resistant
• Nut Quality: Good, variable sweetness
• Varieties: Qing, Gideon, AU-Homestead

European-Japanese Hybrids

• Zones: 5-8
• Size: 35-50 ft
• Blight Resistance: Moderate to good
• Nut Quality: Large, sweet nuts
• Varieties: Colossal, Bouche de Betizac, Marrone di Marradi

American Chestnut Hybrids

• Zones: 4-8
• Size: 50-75 ft
• Blight Resistance: Variable (backcross breeding ongoing)
• Nut Quality: Sweet, traditional American flavor

Climate and Hardiness

• Zones: 4-8 depending on variety
• Late Frosts: Chestnuts bloom late, usually avoiding frost damage
• Summer Heat: Tolerate heat well
• Winter Cold: Chinese varieties most cold-hardy

Site Selection

• Sunlight: Full sun essential for nut production
• Soil: Well-draining, slightly acidic (pH 5.5-6.5)
• Drainage: CRITICAL—chestnuts won't tolerate wet feet
• Space: 30-40 ft between trees at maturity
• Avoid: Heavy clay, limestone soils, low wet areas

Pollination

Chestnuts require cross-pollination from a different variety:

• Plant at least 2 different varieties
• Trees should be within 200 feet (closer is better)
• Bloom times must overlap
• Wind pollinated—no bees needed

Planting

1. Plant in spring after frost danger.
2. Dig hole 2x wider than root ball.
3. Set at same depth as nursery (chestnuts are sensitive to depth).
4. Keep graft union 2-3 inches above soil.
5. Water deeply and mulch 3-4 inches, keeping mulch away from trunk.
6. Stake in windy locations.
7. Protect from deer browsing—essential!

Training and Pruning

Training:

• Central leader or modified central leader
• Select 3-5 scaffold branches with wide angles
• Remove competing leaders

Pruning:

• When: Late winter while fully dormant
• Young Trees: Focus on structure and form
• Mature Trees: Light maintenance pruning only
• Remove: Dead, diseased, crossing, and low branches

Fertilizing

• Young Trees: Light nitrogen application in spring
• Mature Trees: Often need little supplemental fertilizer
• Soil Test: Test every 2-3 years and adjust as needed
• pH Management: Add sulfur if pH is too high

Watering

• Young Trees: 1-2 inches per week during growing season
• Established Trees: Drought tolerant once established
• Critical Period: Summer during nut development
• Avoid: Overwatering and standing water

Pest and Disease Management

Chestnut Blight:

• Most devastating disease
• Plant resistant varieties (Chinese or hybrids)
• No cure for infected trees
• Remove and destroy infected material

Phytophthora Root Rot:

• Caused by poor drainage
• Prevention: Plant in well-draining soil only
• Once established, usually fatal

Pests:

• Chestnut Weevil: Larvae feed inside nuts. Hot water treatment or freezing after harvest.
• Gall Wasp: Growing problem. Plant resistant varieties.
• Deer: Protect young trees with fencing or tree tubes

Harvesting

Timing:

• September-November depending on variety
• Harvest when nuts fall from burrs
• Collect daily during harvest season

How to Harvest:

• Gather fallen nuts daily (prevents mold and weevil damage)
• Wear thick gloves—burrs are spiny!
• Discard any with visible damage or holes
• Process within 2-3 days

Post-Harvest Processing

1. Float Test: Submerge nuts in water; discard floaters (bad nuts)
2. Cure: Let nuts dry at room temperature for 2-3 days
3. Store: Refrigerate in perforated bags at 32-40°F for up to 3 months
4. Freeze: For longer storage, shell and freeze up to 1 year

Timeline to Production

• First Nuts: 3-5 years from grafted trees, 5-7 from seedlings
• Significant Production: 10-15 years
• Full Production: 15-20+ years (can live 500+ years!)