Irrigation water that runs off a sloped lawn is inefficient, costs extra money in watering costs and can cause damage to lower areas of the lawn. Wet areas of a lawn on the bottom of a slope lead to pests, mold and mildew lawn diseases and lessen the drought tolerance of those areas. Calibration of your sprinkler system by taking into consideration the amount of water it produces in a given time period helps determine the frequency and amount of water needed for irrigation without runoff.
1 Place baking pans or other shallow containers at the bottom of your sloped lawn.
2 Manually turn on your hose-end timer for a garden hose and sprinkler system, or the irrigation control for an in-ground irrigation system.
3 Write down the time you turn the system on.
4 Allow the lawn to receive water, and as soon as it starts to run off the bottom of the slope, manually turn off the timer.
5 Write down how many minutes you irrigated the lawn until the point of runoff at the bottom of the slope. Set your hose-end timer or irrigation controller so that it only turns on in cycles for the same amount of minutes until runoff occurs.
6 Measure the water depth in each container with a measuring tape. Each container should have about the same amount of water.
7 Determine how many irrigation cycles you need to run per week to administer about 1 inch of water per week to your lawn. For example, if the containers have about 1/8 inch of water in them, set your hose-end timer or irrigation controller to 8 cycles per week for the amount of time determined until runoff occurs.
Items you will need
- Baking pans
- Measuring tape
- Hose-end timer
- Garden hose
- Irrigation system (optional)
- The best time for lawn irrigation is between 5 and 10 a.m. because this is when the air is calmest and the temperatures are cool, meaning less loss of water to the wind or evaporation.
- Keep lawns mowed to the correct height for your type of grass to decrease water usage.
- Adjust sprinklers or sprinkler heads so excess water does not splash against your home, driveways, walkways or into the street.
- Newly established lawns require extra irrigation in short sessions to establish a good root system and promote growth.
- Hose-end timers attach to the outdoor faucet on one end and then the garden hose attaches to the other end.
- Increase the amount of watering cycles if the grass at the top of the slope appears dry when the bottom of the slope is hydrated but not soggy.
- Choose a digital hose-end timer with several cycles on it. Most mechanical timers will only allow one cycle.
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