Carol O'Meara - Colorado State University Extension

Carol O’Meara – Colorado State University Extension

BOULDER COUNTY – What a difference a high pressure ridge makes. After a soft, rainy warmup to the season, gardeners are shocked to face scorching hot temperatures that broil our gardens and lawns.  The high pressure system parked overhead is pulling the heat up from the south and there is nothing our plants can do but weather the heat.

When the heat switched on, lawns stressed, with Kentucky Bluegrass going dormant to escape the near-hundred degree temperatures. Brown spots in yards are blooming faster than the roses. In most cases, the reason for browning is lack of water.

Until the temperatures cool down, help your lawn by giving your irrigation system a quick once-over, looking for broken or tilted sprayers, blockages caused by overgrown plants, or heads sheared off by mowing. Turn the sprinkler system on and closely examine the toss of water from each head and look to see if the water from one head is reaching the sprinkler next to it. This head-to-head coverage is critical for good irrigation coverage. Make sure that the arcs of water reach close to, mid-point- and far from the head.

If you’re standing behind a sprinkler head it will be easy to tell if it’s pointed the wrong way, because you’ll be getting a shower. Choose a warm part of the day to conduct a sprinkler check.

In general, a Kentucky bluegrass lawn needs approximately two-and-a-half inches of water each week, split into several different days of watering. Water deeply by having the sprinklers deliver one to one-and-a-half inches of water per irrigation.

Other factors may add to lawn woes, such as sod that has been placed on poorly prepared soil. When soil is compacted and sod is laid on top, roots barely sink in, growing instead in the thatch layer. Like a turf toupee, these lawns can be lifted from the ground easily by pulling up on the grass. Since thatch doesn’t hold moisture well, the grass is constantly thirsty. Avoid this problem by spending time on preparing the soil for sod, making certain to incorporate compost into the ground.

With any change in irrigation, be alert to signs of trouble. Lawns don’t need water every day, and if you are running your sprinklers that often you may need professional help. Check your lawn before increasing water to it by walking across it the afternoon before watering is scheduled. If the footprints stay visible 30 minutes or longer after walking on it, the grass is drying out a little too much in between watering.

The Colorado Master Gardener program in Boulder County is currently taking applications for the fall class. If you are interested in helping others garden, the Colorado Master Gardener program is for you! Classes run mid-September through mid-December and will be held Tuesday and Thursday evenings, 6 p.m. to 9 p.m. Please contact the Colorado State University Extension Office in Boulder County at 303.678.6238 to receive an application, or on the web at

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 Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, or visit the web site at