Feeling chilly? Although this past week has been relatively warm, January is historically our coldest time of the year. That means one thing to gardeners: Be ready for frost. We’ve had a few chilly nights so far this winter –and probably will have more. Sacramento isn’t out of frost danger until March 23, which is when our frost season usually ends.
Although overnight forecasts may call for temperatures in the 30s, not every garden has the same lows. Take cold nights to evaluate the microclimates within your own garden. Some spots – particularly in low areas away from buildings – are colder than others. Likewise, sensitive plants – such as citrus, succulents and tropicals – get a little extra warmth next to south- or west-facing walls.
If freezing temperatures are forecast, here’s how you can protect your home and garden:
▪ Bring pets indoors. Yes, they have fur coats – but they still get cold!
▪ Water plants lightly in late afternoon or early evening before the frost hits. Wet soil holds more heat than dry soil. This also raises the humidity level.
▪ The plants most at risk are citrus, tropicals, succulents, tender perennials and new transplants.
▪ Move potted plants to overnight shelter such as the garage or covered patio. Or move them close to a south-facing wall.
▪ Cover sensitive plants at night with frost cloths, burlap or fabric sheets – not plastic. Sheets can raise the temperature 5 degrees. Allow a little room for air circulation under the cover; that helps keep in the warmth. But coverings should reach the ground.
▪ Don’t leave these fabric sheets on plants all the time. That will smother the plant you’re trying to protect. Remove the coverings in the morning so plants can breathe and get some sun.
▪ Avoid plastic sheets as frost protection. Clear plastic won’t hold in warmth and black plastic bags will cook the plants you’re trying to save.
▪ String old-fashioned Christmas lights (C-7 or C-9 types) on the trunks and limbs of citrus or avocado trees or large plants. Bigger lights put out more heat than minis.
▪ Cover tender transplants with “hot caps,” individual greenhouses made of waxed paper. Cut a 12-inch piece, form a cone and secure with tape. Place the cone over the transplant. Or use a plastic water bottle with the bottom cut out; discard the cap. Those protectors can stay in place until the frost danger has passed.
▪ Mulch mounds can protect the fragile fruit on strawberries and young leaves on lettuce. Cover whole plants with dried leaves or straw, then carefully remove the mulch after frost danger has passed.
▪ To keep pipes from freezing, wrap pipes in foam protection or insulated tape.
▪ Cover pool or spa equipment with insulated cloths.
▪ Remove water from birdbaths; otherwise, they may freeze and crack.
▪ If plants show frost burn, leave the brown leaves alone until all frost danger is past –after that March 23 cutoff. That damage helps protect the plant from further harm. Many tender perennials and shrubs will grow back if the frost damage wasn’t too severe.