Seeds: Frost leaves Sacramento gardeners feeling chilled

Maybe we were lulled by warm Thanksgiving weather into thinking we live in a perpetual comfort zone. Maybe we forgot to look at a calendar or that it can get really really cold in December. Maybe we just got too busy with holiday bustle or dealing with year-end stress.

Whatever, the killer frost of December 2013 smacked Sacramento where it hurts: In our gardens.

One day, we’re harvesting fresh tomatoes and peppers for Thanksgiving dinner. The next week? Those veggies became blackened blobs.

And that big chill came before it’s officially winter, which starts today.

Our garden survived most of the carnage. The baskets of tuberous begonias, so full and colorful on Thanksgiving Day, now droop like soggy cellophane noodles. Their stems and flowers froze solid and, when thawed, turned to stringy mush, but they’ll come back next year (I hope).

Big red hybrid tea roses also froze on their stems, a pretty sight until they defrosted. At least I know the bushes will recover by next spring.

Not all plants are as fortunate, especially citrus and succulents. Both were particularly vulnerable as temperatures plunged to 24 degrees – and in some places, much lower.

Farmer Fred Hoffman, Sacramento’s go-to garden guru, saw the damage in his own backyard as well as heard about it from scores of other gardeners. The popular radio host devoted segments of his weekly shows (Sundays at 8:30 a.m. on KFBK 1530 AM and 10 a.m. on KSTE Talk 650 AM) and his blog ( to coping with “hard frost,” the classification for dips below 24 degrees.

Any time the temperature goes below freezing – 32 degrees – for two hours or more, tender plants may be damaged. But it’s that extended cold – several hours each night, for extended periods, night after night – that really takes its toll.

“We had eight nights in a row below 32 degrees,” said Hoffman, who lives in Herald. “The coldest it got was 24 degrees, but that thermometer is on the side of the house. I know it’s at least five degrees colder where the plants are growing.”

Some victims were predictable, he noted. “It’s the usual culprits. The alstroemerias are sagging, but they’ll come back. The Swiss chard looks a little sad. The geraniums are all brown; I’ll leave all that stuff (until spring) to protect the roots. They should be OK. The tomatoes and peppers are toast, but that’s incentive to pull them out, something that was long overdue.”

Hoffman used copious amounts of frost cloth and other coverings to protect his tender citrus. Most of his trees seemed to survive intact.

“I’m worried about the Gold Nugget mandarin,” he lamented. “I did everything to give it extra protection. I built a PVC frame and covered it with a tarp. I strung Christmas lights all over the tree and hung a 75-watt shop light inside the tarp. The tree’s still looking like it won’t make it. And it’s a shame; it’s loaded with fruit, but it wasn’t quite ready to pick.”

Tender plants are just part of the problem. Freezing water can do serious damage to pipes, pots and patios. Water finds its way into cracks, then expands and contracts as its freezes and thaws.

“Irrigation lines are an issue; people may have breaks and not even know it yet,” Hoffman said. “I learned my lesson in 1990. Now before a frost, I turn off the (outside) water and open the faucets to empty the lines.

“But I was amazed; a terracotta pot cracked,” he added. “That happens in higher elevations, but not so much here (in the Central Valley). But it’s that cycle of freeze, thaw, freeze, thaw. It’s a reminder; bring terracotta pots indoors in winter.”

Repeated exposure to freezing nights weakened plants, too. According to research in California citrus orchards, trees actually could be damaged at higher (but still freezing) temperatures if they had to endure frost every night. Citrus usually frost-hardy to 28 degrees started burning with just a touch of frost in the air.

“They can only take so many punches,” Hoffman said. “The citrus industry is fearing that as well.”

Location helps backyard trees survive. Every yard has microclimates that stay a few degrees warmer, particularly close to walls, fences, driveways or the home.

During the killer freeze, Sacramento’s Bill Bird protected his frost-tender Duke avocado tree with old-fashioned Christmas lights hung on a tomato cage. It worked: The tree, planted in October, not only survived the frost, but sprouted leaves. It liked the extra warmth at night.

“I’ve learned through the years, by killing four or five trees – at least,” said Bird, who lives in Natomas. “Most of what I’ve learned through trial and error is what to plant where. We have a wide side yard that’s very protected; the lime tree came through fine. The avocado is protected from the north wind with a house on one side, the fence on the other. It’s in a raised bed and I keep it watered. All that keeps it warmer.

“What worries me (is) we’re not out of this yet,” Bird added. “It’s only December.”

To those who got burnt by the frost, Hoffman’s advice is simple: Wait.

“Don’t make any rash decisions,” he said. “Most of the time, plants will come back. Just take stock of the damage. Then, wait until at least March or April before you know for sure (if the plant is dead). You’ll be surprised by how much actually survived.”


Here are more frost tips for this chilly time of year:

• 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 your plant cozy.

• Holiday lights – the old-fashioned kind that get hot, not LEDs – can help keep plants warm, too. Wrap them around the trunk and branches. Keep them 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.

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

• 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.

— Debbie Arrington