Is the Grass Greener on the Other Side of Your Fence?
Keeping It Green
If you plan on maintaining a sizable lawn and want to keep it green during the growing season, a permanent in-ground irrigation system can conserve water and save time, too. A properly installed system can deliver just the right amount of water when and where your lawn needs it, and it eliminates the need to drag portable sprinklers and hoses all over the yard.
In-ground sprinkler systems also make sense for a vacation home that you visit irregularly or if you travel frequently and are not always home in summer to attend to your lawn’s water needs. In these cases you will either need a neighbor to turn the system on and off. It would be much easier on both of you if a monitoring system were installed. The neighbor simply needs to check periodically to see if it is working.
How Permanent Sprinkler Systems Work
A typical in-ground sprinkler system delivers water via a network of underground PVC pipes to all areas of a lawn. It consists of multiple control valves, each of which can either stop or start the flow of water to an area of lawn, or zone. Each zone consists of several sprinkler heads attached to buried pipes by risers (short vertical pipes) that are arranged to provide uniform water coverage to the grass in that area. Systems are divided into zones because household water pressure is capable of supplying only a limited number of sprinklers at one time.
There are two types of in-ground irrigation systems, manual and automatic. A fully automated in-ground system will typically include a programmable controller that allows you to schedule when and where various portions of your lawn will be watered.
A signal from the controller activates a small servo-motor that opens or closes each control valve at the programmed time. Some automatic systems are equipped with moisture sensors (weather or soil) that override the controller program and prevent the system from turning on during rainy weather or after rain, while the soil remains moist. A manual system requires that you turn the control valves on and off by hand.
There are several types of lawn sprinkler heads, including sprayers that deliver a fine, mist-like spray and rotary heads that throw water in a wide circle, much like a portable rotary sprinkler does. Spray-type heads are specified for systems when accuracy of coverage is critical. Rotary heads deliver water to larger areas, so fewer are required. Pop-up varieties of each type of sprinkler head, spray and rotary, rise several inches above grade level when water pressure is introduced. This ensures that groundcovers and low shrubs don’t interfere with water delivery
Sprinkler heads are installed in either triangular or square grid layouts. Make sure that the spray from one sprinkler head reaches the next one, for head-to-head coverage. This allows even coverage. Without overlap, the grass farthest from the sprinkler heads would receive less water than the grass near the heads, whereas some spaces between the sprinklers might not receive any water at all. Many sprinkler heads can be adjusted to control the amount of water delivered. They can also be adjusted to deliver water in a variety of patterns. A full head delivers water in a full circular pattern. The other circular patterns are half, quarter, and adjustable. Adjustable heads can water any part of a circle, from 0 to about 330 degrees. There are also rectangular and square patterns for narrow rectangles of turf or perfectly square areas, and there are end, center, and side-strip patterns for grassy pathways, side yards, and other tight spaces.
Watering With An Irrigation System
One secret to achieving lush, healthy lawns and bountiful gardens is thorough, careful watering, which encourages deep, drought-resistant roots. Both the frequency and method of irrigation and amount of water required vary with your climate, soil, and plants’ needs.
Install an irrigation system that waters the right areas, at the right time, in smaller amounts for maximum conservation. Avoid sprinklers that only scatter water in the air inefficiently. Hire only a professional irrigation contractor who can not only install a mechanically efficient system, but also serve as a guide in choosing and placing your system with conservation of water in mind.
Better Watering: choose the time of day wisely.
Evening and early morning are the best times to water because less water is lost to evaporation than with midday irrigation. Systems are probably best used between 5 p.m. and 9 a.m. Water your lawn and garden before plants show signs of wilting. Wilting stresses plants and may cause flower and fruit loss, and poor growth.
Determine soil moisture
Dig a 12-inch deep wedge of soil from your lawn or garden. Observe the amount of moisture in the sample. Water only if the top 6 inches of soil is dry. After 30 to 60 minutes, recheck the depth of water penetration in the soil at different places in the irrigation pattern. Move or adjust the sprinklers to achieve uniform coverage. Stop watering when soil is moist at a depth of 6 to 12 inches. To avoid digging test wedges in the future, note the length of time needed to achieve thorough watering.
Believing that more is better, most homeowners over water their lawns by 30 percent with non-automated irrigation systems. This often ends up damaging or killing the lawn. Excess watering causes roots to stay shallow, so the lawn is more prone to stress and damage. It can also increase disease, promote weed or insect infestation, and reduce drought tolerance.
Three key signs will tell you if your lawn needs water are:
• Grass blades are curling.
• The lawn is blue-gray instead of green.
• Footprints stay visible on your lawn long after they are made.
Experts recommend irrigating lawns when 30 to 50 percent of the lawn shows signs of wilt. However, a lawn can be trained to become more drought tolerant. Water it only when needed and mow regularly at the recommended height for your grass type.
Types of Sprinkler Systems
There are different types of sprinkler heads that can be used in your sprinkler system – heads used for trees, shrubs, lawn, etc. that vary in the type of spray pattern they produce, from a fine spray to a solid stream.
However, use only one type of head in your sprinkler system. (i.e. if you want to water your lawn, you have to use all lawn heads, if you lived in a forest, you would use all tree heads) Most heads are adjustable with a 45 to 360-degree coverage from the same head. Also, they are designed to use a low rate of water.
There are two types: rotary sprinkler heads extend above the ground permanently, and pop-up heads are designed to be flush with the ground when off, so you can mow over them.
The water pressure in most residential systems isn’t great enough to water an entire lawn at once. As a result, most systems are divided into circuits, each with its own control valve. Control valves are operated by an electronic controller that turns each circuit on and off according to the schedule you set. Sprinkler heads are designed to throw water in a full circle, a half circle, or a quarter circle.
Planning Your Sprinkler System
Before you have a system installed there are a couple of things that need to be done in preparation. Doing these yourself will save the irrigation professional time, thus saving you money.
The first step in planning your system is to check with your local government building department and get any permits you may need. You also need to know where any underground pipes or water mains are located. Your local Department of public works can tell you this information.
Make a sketch of your property, showing the locations of all structures, walkways and driveways, and trees and shrubs). Call your local utility companies and have them come out and mark the location of buried gas, electrical, and telephone lines. Note those locations on your sketch.
Next, determine your water pressure. Borrow or rent a water pressure gauge and attach it to a hose bibb. Turn the water on full (with all other water in the house off) to find the pressure. Systems vary, but you’ll probably need a minimum of 20 pounds per square inch (p.s.i) pressure to install sprinklers.
Check the flow rate by placing a one-gallon bucket under a hose bibb, turning the water on full (with all other water in the house off) and time how long it takes to fill the bucket. Divide the number of seconds by 60 to find the gallons per minute (gpm) capacity of your line. The result of this test will determine the size of each sprinkler circuit.
Anti-siphon sprinkler valves
Anti-siphon sprinkler valves are a form of backflow protection. Their purpose is to prevent contaminated water from flowing back into the water supply system of your home. Make sure your sprinkler specialist installs these. The absence of anti-siphon valves indicates that someone who lacks adequate plumbing knowledge installed your irrigation system.
Your irrigation pipes retain standing water long after the system is used. This water can become stagnant, harboring bacteria and other microorganisms. In the event of back-siphonage, unsanitary water in the irrigation system could contaminate the potable water supply. For this reason, plumbing codes require that all irrigation lines be equipped with anti-backflow protection. To ensure health safety, you will need to hire a licensed plumber.
Assessing Your System
A well-designed sprinkler system will deliver water evenly to all grass areas. It’s important to select heads that provide the right spray pattern for your needs but that also avoid over spray onto streets, paths, driveways, patios, buildings, and unwary passersby. Also, avoid placing a sprinkler where it will spray directly onto the trunks of trees and thereby damage the bark. The sheer force of the water pressure can score the bark, and constant wetting weakens it, making it more susceptible to pests and diseases. Misdirected spray can also blast the petals off flowers.
If you suspect uneven coverage (several parts of your lawn tend to be dry and brown, for example) try a simple test to be sure your sprinkler system is to blame. Place half a dozen containers, such as tuna cans, throughout the affected area and run your system. Note the depth of water collected in each can and calculate an average depth. Perform the same test in areas that seem to receive adequate water (preferably at the same time of day to avoid variations due to fluctuations in water pressure), and make your comparison. If one area is receiving 3/4 inch of water in an hour and another is only getting 1/4 inch, make adjustments. Otherwise you will have to choose between two evils: continuing to deliver inadequate water to some areas and risking brown patches, or using more water than necessary elsewhere to ensure adequate coverage to areas with an inadequate rate of delivery.
Monitors and Controls
We are changing the way we water our lawns with smart technology that monitors and controls water use to maintain healthy growing conditions for lawns, plants, and trees. A properly irrigated lawn has many benefits. It saves on your water bill, increases property values and quality of life, and can even act as a buffer for fire protection since healthy plants will not burn as easily as dry vegetation.
Know When to Water
Unfortunately, how often to irrigate a lawn is not a simple question. Water requirements vary by grass species, time of year, geographical location, soil conditions, amount of shade, and overall lawn maintenance.
Effective and efficient irrigation is the goal when it comes to lawn and landscape maintenance. Rain shutoff devices and moisture sensors are relatively inexpensive first steps to avoid watering in the rain or when adequate moisture is present. Controllers are an excellent way to ensure landscapes get the right amount of water.
But, to water effectively you must monitor and control the moisture in the soil. Different plants need varying amounts of water. Different landscapes and soils will retain or drain water more quickly. To avoid waste or over watering, shut-off systems should respond when rain or increased moisture levels are detected.
A well-designed irrigation system is a conservation tool. Monitoring and controlling water distribution through smart controllers conserves natural resources and can even earn homeowners a rebate in some communities.
Lawn Monitoring Systems
Smart controllers aren’t new. Technologies were developed years ago that would make residential irrigation controllers smart by measuring the evapotranspiration rate of plants—not irrigating by the clock.
It is important to have “zone by zone control,” where each distinct vegetation area has its moisture needs determined, monitored, and met. Sensors in each zone take readings from the soil and compute them based on conditions for that zone including whether it has sun or shade, flat or sloped area, and sandy or clay-based soil. This provides an LCD display of the status of each zone, indicating whether a zone will be watered on the next scheduled irrigation cycle.
Monitoring and control systems are separate from the irrigation systems themselves, although newer irrigation systems are including enhanced controls.
Winter Tip: Turn the water stop valve, inside the house, off. Open the inside drain and place a bucket under it. Outside, turn the hose faucet and the gate valve for the sprinkler system on. This should get rid of water that is left in the pipes. The automatic drain valves open to let out the water whenever the sprinkler system is turned off. Sprinkler pros use compressed air to blow out the water… the most thorough and reliable method.
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