There’s one question that comes back to us year after year, without fail: Should I be watering my lawn and trees in the winter?
Yes! In fact, you could argue that watering trees in the Winter is the best way to ensure they grow strong roots and have long lives. Why? Because the optimal growing conditions for tree roots is when temperatures are between 32 and 41 degrees Fahrenheit. At these temperatures, non-dormant trees put most of their energy into their root systems, growing out and down, and taking in oxygen, nutrients, and water from the soil. Often in the cold and dry Winter months – especially in Colorado – they’re taking in fewer resources than they can handle and need.
Will not watering in the Winter harm or kill your trees?
It’s unlikely, unless it’s been an especially dry year, but non-native and deciduous trees probably need a little more attention than you’re giving them. During the winter, you should water trees about once per month when temperatures aren’t freezing.
How to Deep Water
Deep watering is all about soil saturation in the root area of trees, plants, and turfgrass. In general, you should make sure that your watering saturates the soil to a depth of at least 6″. You can test this with a screwdriver – about a half an hour after you’ve watered, gently pierce the ground with the screwdriver. Saturated soil will easily part for the screwdriver to pass through, so when you start to feel resistance, you’ve reached dry soil.
You should only water in the middle of the day when it’s sunny and temperatures are above 40°. This will allow for moisture to soak into the soil and reach the roots of trees, shrubs, and other plants without freezing.
Even your lawn needs to be watered about twice per month in the Winter, depending on snowfall. As a general rule of thumb, lawns need about 2 inches of water each month in the Winter, so if you haven’t had at least 20 inches of snow in the last 30 days, you’ll need to water at least once.