Last week, we talked about strategies to protect your citrus trees from any expected mild frosts, when morning temperatures dip just below 32 degrees for an hour or two.
But what if the often predicted fall/winter freeze, when temperatures fall into the 20's for several hours each morning, settles into the area? The National Weather Service is forecasting overnight lows to dip below freezing, with many places just outside Sacramento falling into the 20's Tuesday, Wednesday and Thursday (Thanksgiving) this week. What else needs to be done in the yard to prep for a prolonged freeze when temperatures are forecast to fall to the upper 20's for several hours?
Many of us learned this drill back in 1990, when consecutive low morning temperatures of 22, 18, 21 and 23 in Sacramento descended upon us during the period of December 21-24. Temperatures did not get above 25 degrees in parts of the San Joaquin Valley for three to five days and all time record low temperatures were set at Sacramento, Stockton, and Bakersfield. Many records were set for duration of freezing temperatures. The agricultural industry was devastated as acres of trees, not just fruit, were destroyed. Thirty-three counties were disaster-declared.
Homeowners learned which plants don't like it cold (hibiscus, geraniums and other plants popular in the Bay Area and Southern California); and, which plants were the hardy survivors (another reason the oleander was chosen for the Highway 99 median strip).
Here's a last minute checklist for your home and garden if the TV weather people tell you tomorrow's low will be in the 20's:
• If it hasn't rained, water plants thoroughly, especially container plants.
• If possible, move sensitive container plants next to a south or west facing wall.
• Cover citrus and other sensitive plants with burlap, row cover fabric or sheets (be sure to keep the sheets dry). Tent plastic sheets over the plants; don't let plastic touch plant leaves. A light bulb placed in such a plant can offer a few degrees of protection.
• If using an anti-transpirant polymer coating material such as Wilt-Pruf or Cloud Cover, apply at the warmest time of the day, or at least six hours before an expected frost. However, research conducted at Washington State University concluded that these products may actually be detrimental to certain plants during a freeze. If using these products, thoroughly water the soil around the plant before applying.
• Disconnect hoses and drip lines, removing end caps. Lay out straight.
• To prevent broken grass blades, don't walk on a frozen lawn.
• Remove the lowest sprinkler head to drain.
• Cover unprotected faucets and pipes, including any spa or pool equipment.
• If temperatures are predicted to fall to the low 20's: prevent frozen attic pipes. Let lukewarm water trickle out of the indoor faucet farthest from the inlet. Also, let faucets with pipes running along an outer, north facing wall trickle during the night.
• Ideally, add insulation to attic water pipes.
• Open cabinet doors to get more heat to the pipes. Close the garage door if water pipes pass through the garage.
• Setting your thermostat nightly at 55 can add needed heat to the attic pipes.
• If leaving the house for a Thanksgiving vacation during an expected freeze, turn off the water to the house, and open up the faucet farthest from the inlet. Be sure to turn off your water heater.
• To prevent cracking tile, run your pool and spa equipment during the freezing hours.
• Don't forget about your pets during a prolonged freeze. Bring them indoors at night. Move or replace their drinking water. Break up any frozen water in bird baths.
Their is some good news connected with a possible freeze: populations of yellowjackets, eucalyptus-feeding red gum lerp psyllids and grasshoppers could be greatly reduced in 2011.