With the approach of a dangerous cold spell there are a few pointers that everyone should keep in mind.
Temperatures below 45 F for more than a few hours can be damaging for many of our tropical plants. Tropical aroids, orchids and even some trees can be chilled by these conditions. Most of our common fruit trees can withstand these conditions and even produce a good crop of fruit. Frosts occur at 32F with the formation of ice and less than an hour of frost can be severely damaging. Freezes occur below 30F and are the most damaging events for our tropical and subtropical plants.
• Move orchids and any sensitive potted plants inside or under cover during the cold spell. This includes under a tree canopy.
• If you have irrigation, thoroughly water your plants the day before cold danger. The water in the ground will trap and hold heat and the fully watered plant is also more cold tolerant.
• Cover sensitive plants with a sheet or a cardboard box. Be careful not to touch the foliage to the fabric.
• Place a space heater under the sheet or the cardboard box or in close proximity to any of your sensitive plants.
• If you have a pond, run a hose slightly open during the night to heat the water, save fish and create a heat sink in the yard.
The major concern for most people is a frost. If temperatures are forecast to be in the upper 30s F there is a good likelihood for frost in low-lying, exposed and interior locations. It is better to be cautious than sorry.