Sacramento Digs Gardening: Sub-freezing temperatures in Sacramento forecast

Small citrus tree with frost blanket and lights

This display from the Fair Oaks Horticulture Center a few years ago illustrates how to protect

citrus trees, especially smaller ones, from frost damage. The frost blanket of course would be pulled over the tree to the ground in practice. The chart on the right is a guideline that lists temperatures below which mature citrus trees can be damaged. See the note below for details. (Photos: Kathy Morrison)

Time to pull out the frost blankets!

After months of expecting “possible” frost, the threat of subfreezing overnight temperatures is finally real. According to the National Weather Service, Sacramento could see 29 degrees just before dawn on Tuesday morning. That follows a very chilly night with an expected five to six hours under 32 degrees.

Frost damage occurs when temperatures stay below freezing for more than two hours. So, take precautions this evening:

* Cover your sensitive plants with frost cloth, blankets or cloth sheets (not plastic). Ideally, do this before sunset so radiant heat will help keep plants cozy.

* 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.

* 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.

These C9 Christmas lights can help protect citrus trees.

* 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 exception to this rule are cactus 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 on 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.

Note: Mexican limes are the most vulnerable (29 degrees), followed by Bearss limes (28), Eureka or Lisbon lemons (26), grapefruit (25), Meyer lemons (22), sweet oranges such as navels (21), mandarins/tangerines (20) and kumquats the hardiest (19 degrees). Damage also depends on the duration of exposure to cold.

GENERAL GARDENING

An article about gardening.

Keywords:

succulents gardening Sacramento frost tropical plants frost blankets tender plants citrus trees January irrigation weather

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Food in My Back Yard (FIMBY) Series

FALL

Nov. 11: Prepare now for colder weather in the edible garden

Nov. 4: Plant a pea patch for you and your garden

Oct. 27: As citrus season begins, advice for backyard growers

Oct. 20: Change is in the autumn air

Oct. 13: We don't talk (enough) about beets

Oct. 6: Fava beans do double duty

Sept. 30: Seeds or transplants for cool-season veggies?

Sept. 23: How to prolong the fall tomato harvest

SUMMER

Sept. 16: Time to shut it down?

Sept. 9: How to get the most out of your pumpkin patch

Sept. 2: Summer-to-fall transition time for evaluation, planning

Aug. 26: To pick or not to pick those tomatoes?

Aug. 19: Put worms to work for you

Aug. 12: Grow food while saving water

Aug. 5: Enhance your food with edible flowers

July 29: Why won't my tomatoes turn red?

July 22: A squash plant has mosaic virus, and it's not pretty

July 15: Does this plant need water?

July 8: Tear out that sad plant or baby it? Midsummer decisions

July 1: How to grow summer salad greens

June 24: Weird stuff that's perfectly normal

SPRING

June 17: Help pollinators help your garden

June 10: Battling early-season tomato pests

June 3: Make your own compost

May 27: Where are the bees when you need them?

May 20: How to help tomatoes thrive on hot days

May 13: Your plants can tell you more than any calendar can

May 6: Maintain soil moisture with mulch for garden success

April 29: What's (already) wrong with my tomato plants?

April 22: Should you stock up on fertilizer? (Yes!)

April 15: Grow culinary herbs in containers

April 8: When to plant summer vegetables

April 1: Don't be fooled by these garden myths

March 25: Fertilizer tips: How to 'feed' your vegetables for healthy growth

WINTER

March 18: Time to give vegetable seedlings some more space

March 11: Ways to win the fight against weeds

March 4: Potatoes from the garden

Feb. 25: Plant a fruit tree now -- for later

Feb. 18: How to squeeze more food into less space

Feb. 11: When to plant? Consider staggering your transplants

Feb. 4: Starting in seed starting

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Garden checklist for week of Nov. 16

During breaks in the weather, tackle some garden tasks:

* Clear gutters and storm drains.

* Prune dead or broken branches from trees.

* After the storm, seed wildflowers and plant such spring bloomers as sweet pea, sweet alyssum and bachelor buttons.

* Set out cool-weather annuals such as pansies and snapdragons.

* Lettuce, cabbage and broccoli also can be planted now.

* Plant garlic and onions.

* Plant bulbs at two-week intervals to spread out your spring bloom. Some possible suggestions: daffodils, crocuses, hyacinths, tulips, anemones and scillas.

* Save dry stalks and seedpods from poppies and coneflowers for fall bouquets and holiday decorating.

* Rake and compost leaves, but dispose of any diseased plant material. For example, if peach and nectarine trees showed signs of leaf curl this year, clean up under trees and dispose of those leaves instead of composting them. Do leave some (healthy) leaves in the planting beds for wildlife and beneficial insect habitat.

* Give your azaleas, gardenias and camellias a boost with chelated iron.

* For larger blooms, pinch off some camellia buds.

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