What temperature kills upside-down tomatoes?
Written by
Julia Anderson
Reviewed by
Prof. Charles Hartman, Ph.D.Tomatoes are susceptible to extreme hot and cold conditions, which limit their survival and yield. A temperature of 50°F (10°C) or lower will cause permanent cell damage, and temperatures of 90°F (32°C) or higher will cause blossom drop. You have to keep a close watch on conditions during the growth period. I have protected my upside-down tomatoes with simple tricks I have devised over the past five years.
Cold Damage Prevention
- Cover plants when forecasts predict temperatures below 50°F
- Use insulated cloches or frost blankets overnight
- Move buckets to protected areas during cold snaps
Heat Stress Management
- Install 30% shade cloth when temperatures exceed 85°F
- Mist foliage during early morning hours
- Water deeply before peak afternoon heat
Microclimate Creation
- Position buckets near light-colored walls for warmth reflection
- Use water-filled containers as thermal buffers
- Group plants together for mutual protection
Make provisions for unexpected cold spells with portable protection systems. I use insulated plant cloches for spring and fall's spontaneous weather. Insulated plant cloches will save your tomatoes from unforeseen frosts when correctly covered overnight. Each day, lift the covers once the temperature is higher than 55°F to avoid overheating.
Use evaporative cooling to combat heat stress. I set out shallow trays of water under hanging containers in heat waves. This adds localized humidity that cools the surrounding air very well. You can significantly reduce blossom drop with this simple and inexpensive solution.
Observe the microclimates within your growing situation. My south-facing balcony is 10°F warmer than the north-facing areas, and you'll need to shift plants around every season to avoid temperature extremes. Thermometers placed among the plants provide real-time, accurate temperature readings.
Lengthen the growing season using thermal mass concepts. I first placed buckets next to the containers (I use 5-gallon containers) filled with water that warms the air during the day. When the air temperature drops overnight, they release warmth into the air, keeping plants from experiencing chilling damage. My tomatoes received 3-4 more weeks of productivity with that technique.
Read the full article: How to Grow Tomatoes Upside Down Successfully
