It’s a question I get asked all the time at the nursery: Do you need to water your garden in winter?
The answer is yes.
Yes, your deciduous trees have shed their leaves and your perennials are no longer blooming. But they are just dormant and need water to fuel basic metabolic functions.
Unless we have an amazing amount of moisture consistently throughout the winter, you need to be watering your trees, shrubs and perennials, but less frequently.
NORTHERN ARIZONA IS A DRY, DRY, DRY PLACE
It’s been a brutal season for moisture this year.
Our monsoon season only generated a little over 2 inches of rain this year. It was the driest season for Flagstaff since they started keeping records in 1898. We only got about 25% of the moisture we usually get from mid-June to late September.
And, in even more bad weather news, we haven’t had any measurable snow and by this time we’ve usually had almost three inches.
Plus, we tend to have a lot of windy weather that increases the dryness of the soil. So your plants are probably plenty thirsty.
SO HOW OFTEN (AND HOW MUCH) DO I NEED TO WATER?
You should plan on watering about twice a month during the winter. Because it’s so infrequent compared to the spring and summer, you might want to make sure to note it down on the family calendar or your daily planner. And, of course, you’ll be watering by hand since you should have winterized any drip irrigation system you have.
So how much water is enough during the winter? It depends on the size of the tree, shrub or perennial plant and whether it is new or well-established.
As a general rule, you’ll need about 10 gallons of water for each diameter inch of the tree. For example, a two-inch diameter tree needs 20 gallons per watering. The trick is you need to water slowly; you can’t just dump 10 or 20 gallons of water all at once, as it will run off instead of soaking down to the roots.
Newly planted shrubs require about twice as much water as an established shrub needs. You should be looking at 5 gallons each time you water a new shrub and 2.5 gallons for shrubs planted at least a year ago. Make sure they are surrounded by mulch to help them retain the water.
Perennials vary, but know that those planted late in fall will not have had as much time to establish their roots as the ones you put into the ground this past spring. Winter watering is highly advisable for late-planted perennials and ones located in windy or southwest exposures.
WHAT ABOUT FREEZES?
It’s a good idea to make sure that temperatures are going to hit about 40 degrees on the days you are watering, and you’ll want to water by midday to make sure it’s been absorbed before any nighttime freezes.
You’ll also want to try to water when it isn’t windy out. A drying wind could wind up carrying off the moisture you are trying to get to the roots of your plants.
By watering your garden in winter, you are increasing the chances that your garden, trees, shrubs and perennials will be lovely and lush next spring.
For tips on how to take care of your garden all year long, check out our gardening week-by-week page.
Happy gardening (and watering!)