What temperature is too cold for planting?
Written by
Paul Reynolds
Reviewed by
Prof. Martin Thorne, Ph.D.The dangerously ineffective planting of trees will occur when soil temperatures drop below specific minimums of 40°F (4°C) or lower, and root cells cannot take up nutrients or water. This is due to frozen soil and roots lacking soil contact, as well as freezing air damaging the plant tissue. I have witnessed total planting failures when I disregarded the minimum soil temperature requirements.
Physiological Damage
- Ice crystals rupture root cell membranes below freezing
- Enzyme activity stops preventing nutrient absorption
- Water transport systems fail in frozen conditions
- Cellular repair mechanisms become inactive
Species Vulnerabilities
- Evergreens suffer winter dehydration without water uptake
- Young trees lack protective bark against frost cracks
- Tropical species experience cell death above 32°F (0°C)
- Flowering trees lose next season's buds
Evergreens are especially vulnerable to damage when the temperature falls below 40°F (4°C). The foliage continues to lose moisture when frozen roots are unable to absorb water, which causes fatal winter browning. I safeguard specimens by burlapping the trunks and applying anti-desiccant sprays when planting near this temperature boundary.
Regional differences significantly change cold limits. Mountainous areas require a 5 °C warmer minimum temperature than valleys. Urban heat islands will allow the planting of certain plants at slightly cooler temperatures. Coastal areas require special consideration for wind chill effects. Always use soil, not air temperatures.
Utilize soil warming practices when planting near critical temperatures. Use a dark color mulch to absorb sunlight. Create burlap screen barriers for windbreaks. Irrigate during warm afternoon temperatures when it's possible. Be watchful for unexpected cold fronts and cold snaps in forecasts.
Read the full article: When to Plant Trees for Best Growth
