by Roberta Tolan
Larimer County Extension Agent, Horticulture
Colorado State University Cooperative Extension
One of the easiest ways to conserve water in the landscape is by increasing the efficiency of your in-ground sprinkler system. The following tips, written by Colorado State University Cooperative Extension agents in Eagle and Garfield counties and the Tri-River Area, can help you save water and money.
Use straight-sided containers such as tuna fish or cat food cans, coffee cans, or drinking glasses to determine if the lawn is being watered sufficiently and uniformly. If problems exist, make the necessary corrections.
* The sprinkler system should be checked throughout the watering season for problems. Don't depend on spring maintenance to be sufficient for the season. Foot traffic, autos and lawn mowers often damage sprinkler heads. This can push the top of the sprinkler head below the ground or force the head in a different angle. Both conditions will change the arc of the water and impact the effectiveness of the water application.
* Sprinkler heads tend to fill with grass clippings and soil particles. Check the sprinklers for debris and clean them periodically during the season. Make sure high plants or debris does not obstruct the spray pattern.
* Don't place the timer on a set schedule for the entire season. Rather, adjust it with the changing seasons and developing needs of your lawn. Water lawn areas separately from shrub and flowerbeds as each requires a different amount of irrigation.
* Position your sprinkler system so grass in hot areas is watered separately from turf with a northern or eastern exposure as these areas have different watering requirements.
* Place sprinklers so that water from one head strikes the neighboring head; inadequate overlap results in dry spots.
* Install only as many heads on an irrigation zone as the water pressure can handle; dry spots will occur if there are too many heads on a zone.
* Do not install different types of sprinkler heads in the same irrigation zone. Rotary, spray heads, and impact sprinkler heads put out different amounts of water. Impact sprinkler heads may put out as little as 1/2 inch of water per hour, while pop-up spray heads may apply up to two inches of water per hour. Installing different sprinkler heads in the same irrigation zone will create dry areas in some places while over-watering in others.
* Replace broken or missing sprinkler heads.
* Adjust heads so that water is not thrown onto streets and driveways.
* Water deeply and infrequently to develop deep root systems.
* To reduce water loss due to evaporation, water at night between 9:00 p.m. and 9:00 a.m.
Q: I've heard that mulch helps retain water. Can you tell me what I can use?
A: Yes, mulch helps reduce evaporation from the soil surface and can cut water usage by 25-50%. Mulch also helps stabilize the soil, prevents or moderates soil compaction, controls weeds, moderates soil temperature, and gives your garden a finished look. Some good organic mulch includes wood/bark chip mulch, straw, dried leaves, and grass clippings. Rock over black plastic is very undesirable for planting areas because it can reduce air and water infiltration into the root zone.
Q: How do I know if I have thatch?
A: Thatch is a tight, brown, spongy, organic layer of both living and dead grass roots and stems that accumulates above the soil surface. It can be easily measured by removing a small piece of turf. Interactions between environmental and soil conditions, grass species and management practices (irrigation, mowing, fertilization) influence the rate and extent of thatch accumulation. Grass clippings do not contribute to thatch accumulation and should be returned to the lawn during mowing to recycle the nutrients contained in them. Light shallow power raking can be beneficial if done frequently enough. Core cultivating/aerating is a more beneficial thatch management technique because it helps improve the root zone environment while simultaneously helping to control thatch accumulation.
Q: Seed stalks on rhubarb, what do you do with them?
A: Remove seed stalks and stop harvesting when the temperatures rise above 85 degrees. Remove old stalks at the base, giving room for new stalks to grow. Try not to remove more than 1/4 of the stalks at one time. Rhubarb is a poor competitor for water and nutrients so keep the plant mulched.
Army cutworms, our “Colorado Miller Moths” are more of a nuisance than a problem when they get in the house or the car. They do not breed indoors and die within a few days. Just vacuum them up. The larvae overwinter on the eastern plains and the moths then migrate to higher elevations to feed on flowering plants during the summer.
Condition your turf for drought with less frequent and deeper watering. Let the condition of the soil and grass determine when you will water instead of arbitrarily watering every few days. If you can push a screwdriver into the soil easily to a depth of 3” to 4”, the yard probably doesn’t need water. However, if the turf has a blue-gray appearance and your footprints remain visible for a few minutes after walking across the lawn, it’s time to water.
It should be safe now to set out transplants of peppers, eggplants, melons, squash and tomatoes. Floating row covers will give a couple of degrees of protection if the temperature drops or keep some buckets or blankets handy – just in case. Direct seed beans and corn into the ground.
Oystershell scale is an insect that attacks ash, cotoneaster, dogwood, lilac and poplar – including aspens and cottonwoods. One control is to apply dormant oil in late winter or early spring before bud break. Control is possible during the crawler stage (mid May to mid June) with the newer “summer oil” sprays that are usually safe to use on plants that have leafed out.
The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.
Gardening and Insect Fact Sheets are available on-line by clicking HERE.
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