winter watering

Carol O'Meara, Colorado State University Extension

Carol O’Meara, Colorado State University Extension

BOULDER COUNTY – When January rolls in, a lot of gardeners get itchy for spring. Seed catalogs tease us; we stare wistfully out windows, and pace restlessly in garden sections of stores. Nesting activity begins with clearing of spaces for seed trays and Christmas lights give way to the warming glow of grow lights shining through windows. It’s a natural part of the season and we embrace this.

What we don’t embrace is the plants giving in to spring fever. Reports of crocus nosing up through mulch and early trees swelling buds are causing a flurry of calls to the office with gardeners wondering what they should do.

Since the crocus won’t be shoved back into the soil and the trees won’t hold their buds no matter how much we admonish them to, the best thing to do is tuck them back in with a drink of water. Make sure the mulch is at least three inches deep around your perennials and bulbs by topping off any that’s been thinned by wind.

Then find time to drag a hose out and water the entire landscape – trees, shrubs, perennials, and lawns. This winter has been extremely dry; there will be consequences on the landscape from below average moisture. To prevent this, water once per month now through March if we don’t get an inch of water through snow or rain.

Make it easy: Measure snowfall at your house with a ruler; don’t rely on total accumulation listed in the news. Write each storm’s amount on your calendar and add it up every four weeks. If it’s less than 12 inches of snow, it’s time to water.

How: Warm days when temperatures are above 40 are best for watering. Choose days when no snow is on the ground and the soil isn’t frozen. In cold weather, water should be trickled slowly into the soil.

Make it easy: Coil a soaker hose so that it spirals out from around the tree and leave it there for use over the next few months. Long hoses can be used to water several trees of the same size at the same time. Have an inexpensive timer on the faucet automatically shut off the hoses, or set timers in the house to remind you to turn off water.

Where: The dripline of the tree is the best place to water, which is the area directly under the tips of the branches. The place to soak is two to three feet on either side of the dripline, to a depth of 12 inches. But many tree roots extend well beyond the canopy, especially more mature trees. CSU Extension Turf Specialist, Dr. Tony Koski, tells us that the easiest way to water older trees is to water the lawn. You’ll give the tree a drink while keeping your lawn’s root healthy too.

Tip for success: Soil needles work best if the ground is soft, and be sure to insert it only eight inches deep. The roots taking up water are shallow, in the top 12 inches of the soil.

How much: Researchers are still working on this, but a good rule of thumb is to give your trees 10 gallons of water per diameter inch of trunk for them to survive. Perennials and lawns just need a good, deep soaking.

Be sure to disconnect the hose from the faucet after you’re done watering and cover the faucet with a protective Styrofoam cone to keep it from freezing.

By Carol O’Meara, Colorado State University Extension. Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Colorado State University Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail [email protected] or visit