What Should You Do For Your Plants AFTER a Freeze?

Sometimes a gardener feels as if they're in a heavyweight boxing match: Your Tender Plants vs. Mr. Freeze. Your citrus, succulents and perennials that may thrive in milder climates might be able to take a frosty punch or two here in the Sacramento/San Joaquin Valleys, foothills, and inland portions of the Bay Area. But several cold blows to the flowers, leaves, stems and roots? 

We aren't talking about light frosts, or temperatures that hover around 30 degrees (F) for a couple of hours; that would be normal; the possibility of a frost in Sacramento is anytime between November and late March. The most typical frost period here is December and January. Usually by late February, gardeners thoughts - mistakenly - have turned to planting warm season annuals and putting away the frost cloths for the season. What area gardeners are going through right now is several days of extended hours of below freezing overnight temperatures, with prolonged bouts of plant-killing cold in the mid-to-low 20's. 

So, what should a shivering gardener do...after a hard freeze, when temperatures are at or below 28 degrees for several consecutive hours? Should they:

a) remove all plants that look frost-bitten; 

b) prune away all freeze-damaged plant parts;

                   

c) Purchase and plant again this month those same varieties of trees, shrubs, perennials and annuals;

                 

d) Water the garden, even if the plants resemble toast;

            

e) Fight the urge to prune and plant by staying indoors, next to the wood stove.

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

If plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

New growth beneath the frosted branches of a geranium.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. Keep the shears in the garage and let the dead portions of the plants protect the understory.

 

 It may take until mid-Spring before you see new growth. Patience is key before you pick up the pruners. In the meantime, tolerate the ugly.

Make sure your garden and potted plants remain moist, especially if it isn't raining. Water gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

Succulents, such as cactus, are the exception, however. According to the Arizona-based Desert Botanical Garden, most succulents survive freezing temperatures best if the soil around them is dry. 

It's dead, Jim.

Some of those dead plants may be summer annuals that survived our unusually mild early and mid-winter. This impatiens,  for example took its sweet time to croak. Mornings hovering around 25 degrees can do that to a summer annual. Put them in the compost pile; plant more in the spring, after all danger of frost.

Frosty the Ficus

What about those plants that have frozen past the point of no return? Should you replace them with the same varieties? That frozen ficus may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"




Oh, and keep your frost protection gear handy...just in case.

What to Do After a Hard Freeze

Sometimes a gardener feels as if they're in a heavyweight boxing match: Your Tender Plants vs. Mr. Freeze. Your citrus, succulents and perennials that may thrive in milder climates might be able to take a frosty punch or two here in the Sacramento/San Joaquin Valleys, foothills, and inland portions of the Bay Area. But five or six chilling blows to the flowers, leaves, stems and roots? 

We aren't talking about light frosts, or temperatures that hover around 30 degrees (F) for a couple of hours; that would be normal for this time of year. What area gardeners are going through right now is a week of extended hours of below freezing overnight temperatures, with prolonged bouts of plant-killing cold in the mid-to-low 20's. 

So, what should a shivering gardener do...post hard freeze? Should they:

a) remove all plants that look frost-bitten; 

b) prune away all freeze-damaged plant parts;

                   

c) Purchase and plant again this month those same varieties of trees, shrubs, perennials and annuals;

                 

d) Water the garden, even if the plants resemble toast;

            

e) Fight the urge to prune and plant by staying indoors, next to the wood stove.

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

If plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

New growth beneath the frosted branches of a geranium.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. 

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March.

So, keep the shears in the garage and let the dead portions of the plants protect the understory.  

It may take until mid-Spring before you see new growth. Patience is key before you pick up the pruners. In the meantime, tolerate the ugly.

Make sure your garden and potted plants remain moist, especially if it isn't raining. Water gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

Succulents, such as cactus, are the exception, however. According to the Arizona-based Desert Botanical Garden, most succulents survive freezing temperatures best if the soil around them is dry. 

It's dead, Jim.

Some of those dead plants may be summer annuals, such as this impatiens, which took its sweet time to croak. Mornings hovering around 25 degrees can do that to a summer annual. Put them in the compost pile; plant more in the spring, after all danger of frost.

Frosty the Ficus

What about those plants that have frozen past the point of no return? Should you replace them with the same varieties? That frozen ficus (or avocado tree) may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"




Oh, and keep your frost protection gear handy...just in case.

Hard Freeze Forecast? Here's What to Do.

 The National Weather Service has issued a hard freeze warning for many areas of Northern California for Saturday night - Sunday morning, January 13. 

Freeze Protection for Lemon Tree

Frozen Hosta

Here is that warning, in its original ALL CAPS glory:









THE NATIONAL WEATHER SERVICE IN SACRAMENTO HAS ISSUED A HARD FREEZE WARNING FOR THE SACRAMENTO VALLEY...DELTA AND NORTHERN SAN
JOAQUIN VALLEY...WHICH IS IN EFFECT FROM 3 AM TO 9 AM PST SUNDAY.

* TEMPERATURES: MINIMUM TEMPERATURES WILL RANGE FROM THE UPPER TEENS IN COLDEST AREAS OF THE VALLEY TO UPPER 20S IN LARGE URBAN  AREAS. DURATIONS BELOW 28 DEGREES OF 3 TO 6 HOURS ARE LIKELY.

* TIMING: LATE TONIGHT AND SUNDAY MORNING.

* LOCATIONS INCLUDE: REDDING...CHICO...YUBA CITY...SACRAMENTO...VACAVILLE ... FAIRFIELD ... STOCKTON...MODESTO.

* IMPACTS: LONG DURATIONS BELOW FREEZING WILL KILL UNPROTECTED FREEZE SENSITIVE VEGETATION. EXPOSED WATER PIPES COULD BURST.
 
 PETS AND LIVESTOCK FEEL THE EXTREME COLD AS WELL.

A HARD FREEZE WARNING MEANS SUB-FREEZING TEMPERATURES ARE IMMINENT OR HIGHLY LIKELY. 
THESE CONDITIONS WILL KILL CROPS AND OTHER
SENSITIVE VEGETATION.

Here's a last minute checklist for your home and garden if the TV weather people (or panicky bloggers) tell you tomorrow's low will be in the mid-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. For best protection, sheets should reach all the way to the ground around citrus trees and other freeze-susceptible plants.
 
• 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. Read and follow all label directions. If using these products, thoroughly water 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.

Protect exposed pipes around wells and pumps

  



• Cover unprotected faucets and pipes, including any spa or pool equipment.



 
• To 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.  
 
• 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 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. 

 




• Cover the worm bin, too!

After a Freeze, What Should a Gardener Do?

After several days of bone-chilling mornings with temperatures dipping into the low-to-mid twenties, should shivering gardeners:

a) remove all plants that look frost-bitten; 

b) prune away all freeze-damaged plant parts;

                   

c) Purchase and plant again this weekend those same varieties of trees, shrubs, perennials and annuals;

                 

d) If it isn't raining, water the garden, even if the plants resemble toast;

            

e) fight the urge to prune and plant by staying indoors, next to the wood stove.

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

Even if plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

New growth beneath the frosted branches of a geranium.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. 

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March.

So, keep the shears in the garage and let the dead portions of the plants protect the understory. It may take until mid-Spring before you see new growth; patience is key before you pick up the pruners.

Make sure your garden and potted plants remain moist. Water gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

It's dead, Jim.

Some of those dead plants may be summer annuals, such as this impatiens, which took its sweet time to croak. Mornings hovering around 25 degrees can do that to a summer annual. Put them in the compost pile; plant more in the spring, after all danger of frost.

Frosty the Ficus

And what about those plants that have frozen past the point of no return? Should you replace them with the same varieties? That frozen ficus may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"

Frost/Freeze Season Approaches. Is Your Yard Ready?

 The typical Sacramento-area frost season (when temperatures dip to 32 or below for short periods of time) is fairly short: primarily, December and January.

However, November frosts do happen here with regularity. 

The earliest frost date for Sacramento was on a November 4, back in 1935, when the morning low fell to 30 degrees. The latest frost date recorded was on March 27, 1898, with a low of 32.

Last year, the first frost occurred on Nov. 17, when the  temperature at Sacramento Executive Airport dipped to 32. The last frost of the 2009-2010 season? March 19, when temps fell to 32 in Marysville and several other locations around Sacramento.

What is cold? Some definitions:

Frost: temperatures dip to 32 °F (0 °C) for short periods of time. Occurs with fair skies and light winds.

Freeze: temperatures at or below 32 °F

Hard Freeze: temperatures below 28 °F for several hours.

This morning (Oct. 27), temperatures here dipped to 38, cold enough to create frosty windshields. Which means that fruit-laden citrus trees could be threatened in the weeks ahead. Some tips for the upcoming cold mornings:


Before a frost:

• Identify cold spots in landscape by monitoring with a thermometer that registers high and low temperatures.

• Identify plants at risk: citrus, succulents, tender perennials, tropical and subtropical plants.

• Have supplies ready: sheets or frost cloths, lights, wraps for trunks, thermometers, stakes or framework to hold covers off foliage.

• Prepare tender plants: avoid fertilizing and pruning after August to minimize tender new growth. 

• Plant insurance: In September and October, take cuttings from frost sensitive perennials; keep cuttings in a sunny, indoor area.

• Rake away mulch to allow soil to warm up during the day and radiate heat at night into plant.

• Monitor weather forecasts and note how low temperatures will be and for how long. 

 

When a frost is forecast:

1. Move potted plants to a warmer spot next to house or under patio cover, especially on south side.

 2. Check that plants are well watered since dry plants are more susceptible to damage, and moist soil retains heat better than dry soil.

3. Cover plants with a row cover before sunset to capture ground heat radiating upward at night, but remove covers daily if it is sunny and above freezing to allow soil to absorb heat.

4. Add heat by using outdoor lights: hang 100 watt drop lights or Holiday string lights to interior of plant. Use the old C7 or C9 large bulbs, not new LED lights which do not give off heat.

5. Wrap trunks of tender trees if hard freeze is expected, using towels, blankets, rags, or pipe insulation.

6. Harvest ripe citrus fruit. Generally, both green and ripe fruit are damaged below 30 degrees, but there is some variation by species (refer to the chart in UC/ANR Publication 8100, "Frost Protection for Citrus and Other Subtropicals").


When a Freeze or Hard Freeze is Forecast (temperatures remain at or below 28 degrees for several hours)

  1. Wrap any exposed plastic water pipes; cover outdoor faucets, as well. Turn off the water supply to outdoor irrigation faucets, if possible. Allow those faucets to drain.

 





2. Disconnect garden hoses and lay them out straight...away from driveways!


3. Adjust your pool, spa or pond filtration timers so that they are running when the chance of freezing temperatures is greatest, between two and nine a.m. Moving water is less susceptible to freezing.

After a frost:

1. Identify damage: dark brown or black leaves and twigs.

2. Wait to prune out damage until after danger of frost is past, and new growth begins in spring.


3. Make sure the backyard birdbath isn't frozen over in the morning. Daily fresh water for dogs and cats is also a good morning habit.