Just how much water should we be putting on our trees during the winter?
That thought came to me last night when the wind whipped up and the next day was another sunny warm one. This is our Winter? The rain hasn’t been offering much over the last few months, so even though the trees are dormant for now, they still are expecting Mother Nature to rain on them.
Does that mean that I have to be a nurturing “Mom Nature” for them?
We’re down nearly 12 inches of rain here and in LA basin they reported a lack of 20 inches. So that means that the roots in our desert soil — clay to sandy to loamy — depending on the region, will dry out and stay dry unless we supplement with some watering days.
But there again, how much?
The Sacramento Bee newspaper is reporting a drought year, and making plans: A state official referred to a dismal first regular snow survey of the winter season, conducted by DWR on Jan. 3 at locations throughout the Sierra Nevada. It found the snowpack at 19 percent of average on that date. In the five days since, the snowpack has shrunk to 17 percent.
This comes after two dry years, which left many reservoirs in the state depleted. Folsom Reservoir in the Sacramento area was at 18 percent of capacity on Tuesday. Water agencies that depend on the reservoir have begun enacting water conservation orders. The U.S. Bureau of Reclamation has cut flows into the American River to levels not seen in 20 years, the paper reports.
How can I tell if my tree is under drought stress?
Symptoms of drought injury to trees can be sudden or may take up to two years to be revealed. Drought injury symptoms on tree leaves include wilting, curling at the edges, and yellowing. Deciduous leaves may develop scorch, brown outside edges or browning between veins.
Evergreen needles may turn yellow, red or purple. They may also turn brown at the tips of the needles and browning may progress through the needle towards the twig. In early summer conifers under drought may exhibit wilted or drooping leaders.
Often times, drought stress may not kill a tree outright, but set it up for more serious secondary insect and disease infestations in following years. And that’s what happened to one of my biggest pines last year.
How much water your tree should receive depends upon the tree size. A general rule of thumb is to use approximately 10 gallons of water per inch of trunk diameter for each watering.
You can easily determine trunk diameter by measuring the circumference of the tree at knee height and dividing by 3. (It can get complicated but it’s worth knowing)
Remember, water should be distributed evenly out under the natural drip line of the tree.
The best watering method depends upon whether you have a small (1-7″ diameter), medium (8-15″ diameter) or large sized (16″+ diameter) tree.
Newly planted and smaller trees can get adequate water within the existing watering restrictions by hand watering with a soft spray hose attachment as a separate zone on your designated day.
Small trees are best watered using the following methods:
• Automated drip irrigation system/soaker hose.
• End of the hose using a soft spray attachment at medium pressure 5-gallon bucket (with ¼” holes
drilled in bottom) or watering bags – filled and set under the drip line.
Medium sized trees are best watered using the following methods:
• Soaker hose coiled several times under the drip line of the tree.
• End of the hose with a soft spray attachment to disperse the flow – use a medium pressure.
Healthy mature trees should be able to withstand a short-term drought. Large trees are best watered using the following method:
• End of the hose with a shower like hose attachment to disperse the flow, use medium pressure.
Here’s the clincher: It’s recommended to water for 12″ of depth to saturate the root system for a minimum of one a week. Yikes! I may not be watering my trees enough even in a good year!
Are You in a Drought Restricted Area?
Be sure to check ahead of time to see if you are restricted by the amount of water you can use. High Desert residents may not be facing any restrictions yet. But don’t be surprised if the warnings go out soon.
Avoid Light Watering — Too Little Causes Problems, too
Don’t dig holes in the ground in an effort to water deeply. This dries out roots even more. I used to think that was an easy method. Wrong.
Don’t spray overhead on the trees because that will just dry it out move due to fast evaporation, and should be avoided during drought conditions even more.
Small- to medium-size trees can be irrigated economically with slow-release watering bags, even gallon milk jugs with small holes punched in the base, or with inline emitters, or a soaker hose attached to your faucet and controlled with a simple battery-operated timer.
More Info is Coming As I Learn the Best Practices For Watering in the Desert