IIn Colorado most lawns are comprised of cool-season grasses. Kentucky Bluegrass is the most popular grass accounting for 95% of all turf areas. Tall Fescue is second and becoming more popular. The growing season for these grasses is April to October. A well designed and maintained automatic sprinkler system is highly recommended in Colorado to maintain turf and to use water wisely. The following information applies to Kentucky Bluegrass and Tall Fescue.
Watering your established lawn varies depending on: the time of year, weather, sun, shade, slope, wind, and temperatures. Watering uniformly, deeply and infrequently will help keep your lawn healthy. Judgment and common sense are important in determining when your yard needs water. A healthy, deep-rooted lawn attained through less frequent, deep irrigation often withstands minor drought better than an over-watered lawn. It is important to water if your lawn dries out and becomes drought-stressed between waterings. The following are signs your lawn needs watering:
- 1st Stage — Grass blades turn bluish-gray
- 2nd Stage — Footprints are left when walked on
- 3rd Stage — Grass blades turn straw color
IIf any of these stages start to appear in your yard, it needs water. You can also use a screwdriver to determine how much moisture is in your soil profile. If the screwdriver goes in easy, it should have good moisture. If it is hard to push it into the yard, your lawn may be dry. During times of extreme summer heat, your established lawn may need to be watered 3 to 4 times a week. Also, a lawn growing in sandy soil will need to be irrigated more often with smaller amounts of water. Sandy soils hold little plant-available moisture. Turf growing in clay soil can be irrigated less frequently.
How Much Water?
To determine how much water a sprinkler zone puts out, put four identical containers at various distances from a sprinkler within its spray pattern. Run the sprinkler zone for 15 minutes. Pour all the water collected from the 4 containers into one and measure with a ruler. Let's say it equals 1”. That means your sprinkler zone put on one 1” of water per hour. Once you know how much your zone puts out per hour, you can adjust them based on monthly needs.
Best Time To Water?
The most efficient time to water is late evening, after 9 p.m. and early morning before 5 a.m. Generally, it is less windy, cooler, and more humid at this time, resulting in less evaporation and more efficient use of water. Water pressure is generally better and this results in optimal distribution patterns. Watering at night does not encourage disease development in Colorado due to the dry climate.
Other Watering Tips
With most soils, do not apply all the water in one cycle or a short period. If water is applied too quickly, it will often run off turf areas due to slopes, compaction, heavy clay soils, and thatches. In these cases, it is more effective to apply half the water in two back to back irrigation cycles. This allows water to soak into the soil rather than runoff. Core cultivation and aeration can resolve some infiltration problems by reducing thatch and reducing compaction.
Mow cool-season grasses 1.75” to 3” tall when the turf is dry to the touch with a sharp blade. A dull mower blade will shred and fray leaf blades instead of cutting them cleanly. The result is a brown, unattractive lawn. Mow often enough so no more than 1/3 of the grass height is removed at any single mowing. If your mowing height is 2 inches, mow the grass when it reaches 3 inches tall. You may have to mow a healthy bluegrass or fescue lawn every three to four days during ideal growing conditions. If weather or other factors keep you from mowing your lawn, raise the height of cut to avoid cutting too much off at one time. Cut the grass again a few days later at the normal mowing height. Pick up the clippings if they form clumps and are matting down and smothering your lawn. During routine mowings, let the grass clippings fall back onto the lawn. Grass clippings decompose quickly and provide a source of recycled nutrients and organic matter for the lawn. Mulching mowers can do this easily. Side-discharge rotary mowers also distribute clippings effectively if the lawn is mowed at the proper frequency. Grass clippings do not contribute to thatch accumulation.
To supply proper nutrition for your lawn, we suggest applying three to four applications of fertilizer per year. Depending on the weather, these applications should be made in March, May, July, and September. How often and what type of fertilizer you use will determine the health of your lawn. If you are watering properly but your lawn is thin, lighter green in color, or is not growing well, your lawn needs to be fertilized. We suggest applying a high analysis fertilizer when your lawn needs a boost. If your lawn is thick and healthy use a slow-release fertilizer.
High analysis fertilizers green up your lawn quickly, promote top growth and develop the root system. Slow-release fertilizers work slower and release nutrients over a longer period. Organic fertilizers work even slower because the organic components must break down before the plant can utilize them. Also, use a fertilizer that is formulated for Colorado soils and our dry climate. We have been selling fertilizers in Colorado for over 45 years. With a minimal amount of work, your lawn will look great and stay healthy.