Feel the chill? So do your plants

The heat from old-fashioned holiday lights can help protect citrus trees during a frost warning. (Photos: Kathy Morrison)

Are you ready for a big chill?

It may seem extra early, but frost is in the forecast for several nights this week – especially in the foothills.

In recent years, Sacramento’s first frost hasn’t hit until mid- to late December. But historically, frost can bite us any time between early November and the first day of spring.

Clear, dry and cool conditions – like what we’re experiencing right now – are more likely to plunge overnight temperatures into the low 30s or 20s than wet weather (which is coming soon). But for the next few nights, we should be on frost alert.

Like any challenge, it’s best to be prepared. Have your frost cloths handy and be ready to bundle up your garden when the forecast predicts 32 degrees or colder.

Keep these frost tips handy, too:

Frost blankets, such as Agribon, also can help protect tender plants. This display by the Sacramento County master gardeners at the Fair Oaks Horticulture Center in 2018 has the blanket pulled up so visitors can see the lights on the tree, but in use the covering would be pulled over the tree to the ground.

* If there is a frost warning, cover your sensitive plants with frost cloth, blankets or cloth sheets (not plastic) before sunset so radiant heat will help keep them cozy. Make sure the cloths go down to the ground to hold in that heat.

* Remember to uncover plants during the day (especially if it’s sunny) or they can be smothered by their frost protection.

* Harvest ripe citrus that may be harmed by frost. Don't let oranges, lemons and other fruit freeze on the tree. (But don't pick them if they're not ripe -- citrus doesn't ripen off the tree.)

* Citrus trees (particularly young trees) tend to be susceptible to frost damage. Limes are the most frost-tender. Make sure they get some protection before frost hits.

* Wrap trunks of young citrus trees to insulate them from frost.

* Holiday lights – the old-fashioned kind that get hot, not LEDs – can help keep plants warm, too. Wrap a string of lights around the trunk and branches. Keep the lights on all night.

* With some exceptions, keep plants watered. Frost injury occurs when ice crystals form on leaf surfaces and draw moisture out of the leaf. The damage from dehydration is what causes frost burn.

* The exemption to this rule are cacti and succulents, where saturation can cause more damage. Also, such tropical plants as bananas and hibiscus may rot if over-saturated before frost, so they prefer to be kept of the dry side.

* Don’t overprotect. Plants are more frost-resistant if they’ve experienced some cold weather and winter hardening.

* If frost damage occurs, wait until March or April to prune off browned branches. That injured area will help protect the rest of the plant from further frost burn.