Many homeowners irrigate their lawns incorrectly. Overwatering is the most common mistake; it can damage or even kill the lawn. Overwatering leads to a shallow root system; increases a lawn's vulnerability to weeds, insects, and diseases; reduces drought tolerance; increases thatch; encourages excessive growth; and reduces tolerance for environmental stress.
Letting your lawn “tell you when to water” means turning your irrigation system to “off” and operating it only when your lawn shows signs of drought stress.
Water requirements vary based on grass species, time of year, geographic location, soil conditions, amount of shade, and overall maintenance of a lawn. Because these varied factors each affect a lawn, rigid guidelines for your lawn’s irrigation frequency may not be accurate.
Look for the following signs and consider watering when you see at least one of them:
1. Folding leaf blades. Drought-stressed lawns will curl up their leaf blades lengthwise in an attempt to minimize leaf area. Wilting is best seen on the older leaves of the grass plant, as the younger leaves are not fully developed and may appear wilted even when they are not.
2. Blue-gray color. Drought-stressed lawns turn from green to bluish-gray.
3. Footprints remaining visible. When footprints or tire tracks remain visible on your lawn long after being made, your lawn is experiencing drought stress.
One way to help your lawn endure drought is to encourage deeper rooting (Irrigate only when the grass begins to show one of the three signs of lawn thirst listed above. When you do water, apply the proper amount of water. These practices will increase rooting depth and overall turf-stress tolerance.
To encourage deep rooting, irrigate your lawn deeply and infrequently and mow your lawn at the highest recommended height for the grass type.
Another way to encourage deeper rooting is proper mowing. Mow at the highest recommended height for your grass type, and your grass’ roots will grow deeper. When you mow too low, the grass puts energy into regrowing shoots, rather than establishing deeper roots.
Many areas of the country regularly experience periods of dry weather during the summer. Irrigation is essential in these areas for maintaining attractive, healthy lawns. Lawns that are not properly watered become stressed and may brown and become thin. Weakened turf grass is more subject to certain disease problems, insect damage, and weed invasion.
How Much Water
In a temperate climate your lawn needs approximately 1 to 1.5 inches of water per week for optimal growth. Chances are that you are living in a temperate climate- most of Canada (except for the northern regions), and the upper half of the Uniter States all reside in that temperate region. It just so happens that a can of tuna is typically just over 1 inch tall. Combine a can of tuna with your lawn and what do you get? The perfect watering measurement.
Did you know what many homeowners over water their lawn? The result is a soft, plushy lawn (may be considered a good thing) that grows slower and dies faster as opposed to a lawn that gets a healthy amount of water. This type of lawn also is more prone to weeds, crab grass, and insect infestation.
The solution? Put a can of tuna on your lawn and water once a week. Do not stop watering until the can is full and make sure that you follow this method for all the parts of your lawn. Your lawn benefits most when it receives 1 to 1.5 inches of water all in one sitting as opposed to small waterings a few times per week. For maximum benefit water your lawn early in the morning or in the evening to reduce the amount that evaporates from the sun.
Along with keeping your lawn greener and healthier, following the Tuna Can method reduces the amount of water that is wasted and the amount of energy that is consumed. If you are from a region that lacks a large supply of fresh drinking water your neighbors will thank you. If that doesn't motivate you to go and follow the Tuna Can method, then the decreased water bills should.
This is one of those rare circumstances where there is no down side. You literally get to have your tuna and eat it too :)
Wet a clay soil before it begins to run off the surface. Place a container in the irrigation water pattern and measure the water collected in the container. If the water starts to run off the lawn before the desired amount is applied, move the sprinklers or stop the irrigation and resume after a period of time.
When to Water Regardless of soil type, it is more efficient to water lawns at the first sign of drought stress rather than wait until the lawn is dormant. Initial signs of a water deficit in the soil are wilting of the turf so that footprints in the grass do not spring back after walking on the lawn. An additional sign of drought stress is a blue or gray coloration of turf that is normally brighter green.
Water early in the day if possible.
Given a choice, water early in the day when lawns are normally wet from dew. Avoid midday watering due to excessive evaporation, and at night due to potential increased chances of some diseases gaining a foothold. The exception to this guide is when you are in extremely hot weather and nighttime temperatures don't go below 68 degrees. Then it is better to water in the late afternoon or early evening, providing you don't have watering-time restrictions. Early or late in the day reduces the amount of evaporation that takes place during the very hot day, allowing more water to reach the root zone.
Given a choice, water early in the day when lawns are normally wet from dew. Avoid midday watering due to excessive evaporation, and at night due to potential increased chances of some diseases gaining a foothold. The exception to this guide is when you are in extremely hot weather and nighttime temperatures don't go below 68 degrees. Then it is better to water in the late afternoon or early evening, providing you don't have watering-time restrictions. Early or late in the day reduces the amount of evaporation that takes place during the very hot day, allowing more water to reach the root zone.
Many grasses require 1-2" of water per week during normal summer weather. Hot, dry, windy weather may produce a greater water requirement. Thatch intercepts and absorbs water, preventing water from infiltrating into the soil. Trapping the water in the thatch encourages the grass to have shallow roots, subjecting it to drying. Compacted soils where people walk or play have low water infiltration rates. Lawn aeration will improve infiltration of water in thatched lawns or lawns with compacted soils. Roots from large trees often extend into the lawn area and draw moisture from the soil. More frequent watering may be required for turf under or near large trees. Objects such as construction debris, sewers, or rocks buried in the soil will show up as localized dry spots. These spots will show signs of drought stress early before the remainder of the lawn and may require extra watering.
