Do tree roots grow during fall?
Written by
Paul Reynolds
Reviewed by
Prof. Martin Thorne, Ph.D.Fall prompts considerable root expansion as trees set themselves up for winter rest. Transitioning to cool temperatures below 45-60°F (7-16°C) and maintaining consistent soil moisture are ideal for kick-starting root growth. Trees divert energy from top foliage to underground growth. I have measured root growth more than 12 inches (30 cm) in the fall months.
Physiological Triggers
- Cool temperatures stimulate root cell division
- Reduced foliage growth allocates carbohydrates downward
- Soil moisture improves nutrient availability
- Mycorrhizal fungi activity peaks in autumn
Survival Adaptations
- Roots store energy reserves for winter dormancy
- Deeper growth accesses stable subsoil temperatures
- Established roots prevent frost heave damage
- Enhanced water absorption prepares for spring growth
Soil conditions play a significant role in Fall root expansion. I achieve the best results with stable moisture levels. Mulch helps regulate soil temperatures and extends the growing season. Avoid compacting soil through foot traffic, test drainage, as waterlogged soil suffocates oxygen-dependent root growth.
The region affects the timing of autumn root periods. Northern regions have shorter growth periods before the onset of frost. Coastal areas have longer warm periods. Urban heat island areas can add 2-3 more weeks of growth. Mountain regions require planting earlier before the temperature drops.
Fall-planted trees develop stronger root systems than spring-planted trees. Their roots begin developing months before the stresses of summer arrive. I've documented a 50% improvement in drought tolerance of fall-planted trees. This head start leads to greater development of canopy cover in spring.
Read the full article: When to Plant Trees for Best Growth
