Growing Catalpa Trees from Seed: Timing and Stratification Tips

When to Plant Catalpa Seeds in Michigan

Late July is too late to start catalpa seeds outdoors in Michigan. The seedlings won't have time to establish before winter. Instead, store seeds in a cool, dry place until spring.

Cold Stratification for Better Germination

Catalpa seeds benefit from cold stratification—exposure to cold, moist conditions to break dormancy. Two reliable methods:

1. Refrigerator method: Plant seeds 1 inch deep in moist potting soil, seal the pot in a plastic bag, and refrigerate for 6–8 weeks. Then move to 70–75°F for germination.
2. Outdoor method: Sow seeds in a protected bed in fall; natural winter cold provides stratification. Seedlings emerge in spring.

Seedling Care and Transplanting

• Transplant seedlings to individual pots after they develop two sets of true leaves.
• Grow until 12–18 inches tall before planting in permanent location.
• Choose full sun with well-drained soil; catalpas tolerate various soil types.
• Water regularly during first growing season.

Catalpas are fast-growing, adaptable trees that reward patience with beautiful flowers and distinctive seed pods.