Sprinklers are not created equal. Brands aside, there are 2 major types of heads: sprays and rotors. Sprays are the smaller of the two, you'll find that they are usually covering areas that are smaller and segmented, like a side yard. They have a misting action and are available in different patterns. Rotors, on the other hand, cover large turf areas and move from side to side. Other than the obvious physical differences, these two types have very distinct watering characteristics. As a general rule, sprays put out nearly 3 times as much water, per square inch, as do rotors. This comes as a surprise to many folks, but remember rotors are moving during their operation, while sprays simply remain static- spraying. Lastly, designs can vary greatly between contractors.
In a well designed system there should be uniform, overlapping coverage with matched precipitation nozzles on all heads. Matched precipitation refers to the amount of water a head puts out in relation to the other heads on the same zone. In the case of rotors, a sprinkler covering a corner (1/4 circle) should have a nozzle about half the size of a head covering a half circle because the 1/4 circle head is moving across its designated area twice as often. Since you have to water to your driest spot, you'll be using more water than you need in the other areas if all of the nozzles are the same size. The goal is to apply even amounts of water over the entire area (because of this, it is important to note that rotors and sprays should NEVER be on the same zone). This is the most important area in watering savings. If your system doesn't meet these standards, you should contact your contractor.
The governing rule in scheduling is water conservation while keeping your lawn healthy (and green) with the least amount of water. There are many variables involved, so it's important to understand some basics. First of all, each lawn has unique characteristics like soil composition and exposure to sun. As you may expect, clay soils and shady areas require less water than sunny, sandy areas. For the sake of this discussion, we'll be addressing conditions somewhere in between. So when assessing your situation, make sure you consider these conditions and adjust accordingly. To establish a healthy, drought resistant lawn the roots have to be driven deep into the soil.
To accomplish this, your system should be programmed to water consistently and evenly. If you simply turn your system off when it rains, then back on when it starts to dry out, the roots don't get a chance to dive deeper. A rain sensor is the only way to capitalize on nature's generosity. Grass roots will go where the water is. If you establish and maintain a moisture level in the soil the plant will get stronger (don't forget to feed it!). By spending some time establishing a strong root zone, you will find that later on your lawn will need much less water, even during dry times.
All things considered, the rule of thumb is a 1" a week for the middle of summer. Generally, this translates to around a half-hour on a rotor zone and 12 minutes on a spray zone per day. However, you'll need to factor in all of the variables of your particular lawn. So use these times as your median and work your way up or down in minutes. For example, if you have a spray zone up the side of your drive, it's sunny and sandy, try increasing the set time from 12 minutes to 15 minutes. Always make your adjustments in small amounts. After a few days, you find this zone is still dry, add a few more minutes. Give your changes a little time to take effect. Even professionals have to use this trial and error to calibrate some tricky areas. Fortunately you'll only have to go through this process one time. Once you've determine how much water is actually needed for each zone, it's just a matter of adjusting these times in blocks or percentage based on the time of year or weather conditions. Let's go back to our example. In the springtime, the lawn does not require as much water as it does in the summer. Along with our "drive zone", we have an open front yard with rotors. This zone, we have found needs to be run for 30 minutes each day in the middle of summer (drive zone for 15 minutes). If you determine that you'll only need half the water, simply cut the time in half for the zones (15 minutes on the rotors, 7 minutes on the sprays).
The key is figuring out how much time is needed on each zone under the same conditions. It is extremely useful to use a log when calibrating your system. Write down your times, changes and conditions. Things will become obvious once you can see a history of cause and effect. Since the weather is constantly changing you must be able to easily change with it to effectively manage your watering. An easy way to adjust for spring/fall seasonal changes is to reduce the operating days per week, and leave the station settings set the same all of the time. As the weather gets warmer/drier, you can simply begin adding days. If cool/wet conditions occur, just reverse the process.
Remember: These are only general rules, check your local weather information and contractor for the necessary amount of water due to different conditions (ex: soil, sunlight, rainfall amounts in your local area).
All things considered the optimum time to water is early morning (4 am to 7 am). There are several reasons for this. Grass absorbs water through its roots and as you've read, the deeper those roots are, the better. Because grass uses water through the roots, it's important that the water is at root level when photosynthesis occurs. Watering in the early morning allows time for the water to perk into the ground ready for the sun. Not only is the water in the root zone where it can be utilized, it's also beyond where the sun can evaporate it away. The idea is to maintain a moisture level in the soil, not simply to get the grass wet every day. Since this is the case it's easy to see why watering in the middle of the day is such a bad idea. During the height of summer when evaporation rates soar, over half the water you put down never makes it to the root zone. This means that you need to water at least twice as much as you do when you water in the early morning. It is important to note that this is also the time of day when water is at peak demand. Since this trend of daytime watering has begun, field observations have confirmed a higher occurrence of "ring spot" in lawns that have followed this regimen. Possible reasons could include higher soil temperatures in combination with lingering water may provide a suitable environment for these diseases.
While it is poor practice to attempt regular watering in the afternoon, a brief "syringe" cycle is a good idea when high stress is noted in the lawn. Stress is indicated where "silvery" patches can be seen in the lawn and is a sign that these areas haven't developed the desired root structure. Because these areas are showing stress, they need special attention. Like us, if grass is relieved of stress (given a drink!), the long term health will be improved. A syringe cycle is a short program that runs separately from your morning cycle. Each affected zone should run approximately 1/2 the time of the morning cycle during the hot part of the day. Remember, this cycle cools, it does not water. Many people find it beneficial to run a syringe program after mowing, when stress is high. We recommend using this technique only when necessary and not on a continual basis. Watering in the evening or overnight is not recommended because quite a bit of the water has passed through the root zone by the time sun comes up the next day. Also, allowing water to sit on the lawn while the grass isn't active overnight may make your lawn a desirable host for disease.
Consistency is the key to determining how many days to water. If your lawn is healthy with decent soil, every other day should be sufficient even during hot/dry conditions. However, you may find that you can't seem to maintain a proper moisture level at every other day. Some soils are simply too sandy to hold the water at a proper level and need to be "topped off" more often (every day). This can also apply to a newer lawn that hasn't matured its root zone yet. If you water each day, expect to water for shorter periods than you would on an every other day routine. Either way, with a little attention you can have a beautiful lawn while managing your watering successfully and responsibly.
Two conditions create backflow. The first condition is backpressure; a greater pressure originating in the irrigation system can overcome the drinking water system supply pressure causing a reverse flow condition.
The second condition is backsiphonage; a suction created by the sudden loss of supply pressure, caused by water main breaks, and large demands such as fire fighting requirements.
Backpressure and backsiphonage can occur seperately or together. Different backflow preventers are designed to protect against one or both of these conditions.
Begin watering new turfgrass sod within a half hour after it is laid on the soil. Apply at least 2 to 3 cm. (1 inch) of water so that the soil beneath the turf is very wet. Ideally, the soil 7 to 10 cm. (3 to 4 inches) below the surface should be moist.
Watering Tip #1: pull back a corner of the turf and push a screwdriver or other sharp tool into the soil. It should push in easily and have moisture along the first 7 to 10 cm. (3 or 4 inches), or you need to apply more water.
Watering Tip #2: make absolutely certain that water is getting to all areas of your new lawn, regardless of the type of sprinkling system you use. Corners and edges are easily missed by many sprinklers and are particularly vulnerable to drying out faster than the center portion of your lawn. Also, areas near buildings dry-out faster because of reflected heat and may require more water.
Watering Tip #3: runoff may occur on some soils and sloped areas before the soil is adequately moist. To conserve water and ensure adequate soak-in, turn off the water when runoff begins, wait 30-minutes to an hour and restart the watering on the same area, repeating this start and stop process, until proper soil moisture is achieved.
For the next two weeks keep the below-turf soil surface moist with daily (or more frequent) watering. Especially hot, dry or windy periods will necessitate increased watering amounts and frequency.
For the next two weeks keep the below-turf soil surface moist with daily (or more frequent) watering. Especially hot, dry or windy periods will necessitate increased watering amounts and frequency.
Watering Tip #5: water as early in the morning as possible to take advantage of the daily start of the grass's normal growing cycle, usually lower wind speeds and considerably less loss of water because of high temperature evaporation.
Watering Tip #6: if the temperature approaches 37( C (100( F), or high winds are constant for more than half of the day, reduce the temperature of the turf surface by lightly sprinkling (syringe) the area. This sprinkling does not replace the need for longer, deeper watering, which will become even more critical to continue during adverse weather conditions.
During the rest of the growing season most lawns will grow very well with a maximum total of one inch of water a week, coming either from rain or applied water. This amount of water, properly applied, is all that is required for the health of the grass, providing it is applied evenly and saturates the underlying soil to a depth of 10 to 15 cm (4 to 6 inches).
Watering Tip #7: Infrequent and deep watering is preferred to frequent and shallow watering because the roots will only grow as deeply as its most frequently available water supply. Deeply rooted grass has a larger "soil-water bank" to draw moisture from and this will help the grass survive drought and hot weather that rapidly dries out the upper soil layer.
Proper watering techniques are a critical aspect of lawn watering, equal in importance to the issues of when to water and how much to water. Here are several key factors to proper technique:
Avoid hand sprinkling because it cannot provide the necessary uniformity as most people do not have the patience, time or "eye" to adequately measure what is being applied across any larger areas of lawn. The only possible exception to this guideline would be the need to syringe the surface of the grass to cool it, or to provide additional water near buildings or other heat-reflecting surfaces.
Understand the advantages of different sprinkler designs, because each type has its advantages and disadvantages and its proper use will be determined by the type of sprinkler you select.
In-Ground Systems require professional design and installation and they require routine adjustments and regular maintenance to be most effective and efficient. The greatest mistake made with most in-ground systems is the "set it and forget it" philosophy that fails to account for the changing seasonal water requirements to maximize turf grown or even allowing the system to operate during or following a multi-inch rain storm. Another frequent problem is when heads get out of alignment and apply water to the sidewalk, street or house-siding, rather than to the lawn.
Hose-End Sprinklers range in complexity, cost and durability, but are highly portable and can provide uniform and consistent coverage, when properly placed on the yard and adequately maintained.
Sprinklers that do not throw the water high into the air are usually more efficient because prevailing winds are less disruptive of distribution patterns, the potential for evaporation loss is reduced and trees, shrubs and other plants do not block the pattern (or are very noticeable if they do).
Several times during the growing/watering season, routine maintenance to check for blocked outlets, leaking or missing gaskets, or mis-aligned sprinkler heads is important, regardless of the sprinkler design.
Select sprinklers and systems for uniformity of coverage across whatever area they are designed to water. Inexpensive hose-end sprinklers and in-ground irrigation systems can provide uniform coverage, but they can also be extremely variable and inconsistent in their coverage patterns.
Verify watering uniformity can be accomplished with a very simple and inexpensive method that uses only 4 to 6 flat-bottomed, straight-sided cans (tuna fish, cat food, etc.), a ruler and a watch.
Follow these steps:
Step #1: arrange the cans at random distances away from any sprinkler, but all within the area you assume is being covered;
Step #2: run the sprinkler for a specific amount of time, say a half-hour OR run the water until a specific amount of water is in at least one can, say a 1.5 cm (0.5 inches)
Step #3: measure the amount of water in each can, checking for uniformity. Some variation is expected, but a difference of 10-percent or more between any two cans must be addressed by replacing or adjusting the sprinkler or relocating the system. This measuring method should be used across an entire lawn that has an in-ground irrigation system to assure maximum coverage and uniformity.
Watering difficult areas such as slopes and under trees requires some special attention to achieve maximum benefit and a beautiful lawn. For Slopes, see Watering Tip #3.
For Areas Under and Near Trees you need to know the water requirements for the specific trees, as well as for the grass.
Despite having deep "anchor" roots, trees take up moisture and nutrients from the top six inches of soil...the same area as the grass. Trees and turf will compete for water. Watering sufficiently for the grass may over-water some varieties of trees and under-water others. A common solution is to not plant grass under the drip-line of trees, but rather use that area for perennial ground-covers, flower beds or mulch beds.
The amount of water your lawn requires and receives will determine its overall health, beauty and ability to withstand use and drought. Keep in mind that too much water can ruin a lawn just as fast as too little.
One inch a week is the standard water requirement established for most lawns; however, this will vary between different turf species and even among cultivars within a specie. There will also be varying water requirements for seasonal changes and still more differences brought about because of different soil types.
Look at your lawn to determine its water needs. Grass in need of water will have a grey-blue cast to it, rather than a blue-green or green color. Also, foot prints will still appear after a half-hour or more on a lawn in need of water, while on a well watered lawn foot-prints will completely disappear within minutes.
Use a soil probe, such as a screwdriver or large spike to determine how dry your lawn is. If the probe can be pushed into the soil easily, it's probably still moist, but if it takes a lot of pressure to push in, it's time to water.
Verify watering quantities with the same measuring can method described above, except you will want to note the time it takes for the cans to collect a specific amount of water. For example, if 0.5 cm (0.25-inches) collects in 30 minutes, you can easily calculate that it will take one hour to apply 1 cm (0.5-inches) of water or two hours to apply 2.5 cm (1-inch).
Water timers can help provide consistency and even be programmed or set to turn-off when no one is awake or at home. Some timers measure just the amount of time water is flowing through the devise and you have to know or calculate how long to set the timer for (see item above). Other units measure the number of gallons of water flowing through it. Knowing that 600 gallons per 1,000 square feet equals one-inch of water will help you calculate the timer settings your lawn will require.
This table clearly illustrates the different watering requirements needed for different weather conditions. A properly set schedule for springtime obviously can't keep up with the demands of summer, thus resulting in brown areas due to lack of water. A faulty design is the first thing to be blamed, however scheduling is usually the culprit. Keep in mind, a system should be designed to maintain a moisture level in your lawn evenly, not simply getting the lawn wet.
For example; watering a hypothetical area for say, 15 minutes a day, with cool/humid (like in spring) would never be able to maintain a moisture level with conditions being hot/humid (like in summer). The water would be evaporated before it had a chance to perk into the root zone where it can be used. Also during times of high stress, grass uses more water to stay healthy. Therefore, it is necessary to simply water more to overcome the high rate of evaporation. Using the table, we should at least double the time for the hot/dry conditions to 30 minutes for our area.
This is also the reason we advocate an early morning watering start time. It avoids the high evaporation loss found in the day time, it also gives the water time to perk into the soil, out of reach of the sun and putting it at root level where it can be used by the plant.
Rate per day
|Cool/Humid||under 70°||more than 50%||.10" to .15"|
|Cool/Dry||under 70°||less than 50%||.15" to .20"|
|Warm/Humid||70° to 90°||more than 50%||.15" to .20"|
|Warm/Dry||70° to 90°||less than 50%||.20" to .25"|
|Hot/Humid||over 90°||more than 50%||.20" to .30"|
|Hot/Dry||over 90°||less than 50%||.30" to .45"|
Use this table to determine how much water your soil type can handle before saturation/run-off occurs. As a point of reference, notice the large difference between sandy and clay soils, these factors will help to guide you as to your watering technique.
Keep in mind that this table also reflects each soil's ability to retain water as well. For example, sandy soils don't retain water very well, thus the higher number until saturation. You may decide that you need to water a sandy area more frequently. At the other end of the spectrum, clay soils retain water very well and it takes much less to saturate a given area. It also takes longer to dry out. Because clay is more dense it takes longer for water to be absorbed, or to perk into the soil, thus it holds water better or longer.
As the slope increases, the relevancy of the soil decreases because gravity allows the water to run off (or down) before it has a chance to soak into the ground. Based on your conditions, you can begin to decide how much time to water a particular area.
|Soil Type||0% to 5% slope||5% to 8% slope||8% to 12% slope||12%+ slope|
|Course sandy soils||2.00"||2.00"||2.00"||1.50"||1.50"||1.00"||1.00"||.50"|
|Course sandy soils over compact subsoils||1.75"||1.50"||1.25"||1.00"||1.00"||.75"||.75"||.40"|
|Light sandy/loam soils||1.75"||1.00"||1.25"||.80"||1.00"||.60"||.75"||.40"|
|Light sandy/loam soils over compacted subsoils||1.25"||.75"||1.00"||.50"||.75"||.40"||.50"||.30"|
|Silt/loam soils over compacted subsoils||.60"||.30"||.50"||.25"||.40"||.15"||.30"||.10"|
|Heavy clay or clay/loam soil||.20"||.15"||.15"||.10"||.12"||.08"||.10"||.06"|