Timely Tips for November
Tip Of The Month – Frost Protection In The Low Desert
Most citrus fruit will not freeze unless temperatures drop into the mid 20’s or lower for at least two hours. Lemons, Limes and other thin-skinned fruit on the upper and outer periphery of trees may receive some injury at about 28 degrees. For more information on frost protection, see below:
Climate Information for November in Phoenix, Arizona
Rainfall:
- Average: 0.7 inches
- Record: 3.6 inches (1905)
Temperature (degrees F):
- Average High: 74.9 degrees
- Lowest High: 40 degrees (1919)
- Record High: 96 degrees (1924)
- Average Low: 48.9 degrees
- Lowest High: 71 degrees (1988)
- Record Low: 27 degrees (1931)
Note: Rainfall and temperatures vary widely within the valley depending upon elevation and microclimate.
Frost Protection In The Low Desert, Continued
MANAGEMENT
Prevention:
- Plant frost sensitive plants in the warmer microclimates of your yard, on the South or West sides, up next to a block wall which will capture and store heat energy from the sun.
- Wrap the trunks of young citrus and other cold-tender trees to protect them from the frost. These wrapping may be left on during the frost season.
- Cover the canopy of trees with a sheet or blanket (not plastic) that extends all the way to the ground. Apply covering by sunset to capture the radiant heat trapped during the day. Remove the covering every morning and reapply at night if frost is forecast.
- Keep trees properly irrigated as drought stress makes them more vulnerable to frost damage.
- If necessary hang an outdoor light just off the ground, well away from the trunk, under the blanket to provide additional heat.
Treatment:
- Do not prune frost damage out until new growth has started in the Spring.
- Pruning stimulates new growth and you do not want to encourage any vulnerable new growth until all danger of frost has passed.
- The damage often appears much worse than it is. What appears to be dead may actually sprout new leaves in the Spring. By pruning before Spring you may cut away much more than is necessary.
- The frost damaged material provides some frost protection to the rest of the plant by creating a “dead air space” which insulates the tree.
