Irrigating Effectively During Times of High Demand
Irrigating Effectively During Times of High Demand
For most of the country August is a hot and dry month that requires high amounts of water to keep landscapes performing. Commonly, many irrigation consumers simply increase how long the irrigation system runs in an effort to increase the amount of water delivered to the landscape. While raising run times will increase water, it may not be the most effective way to offset the watering demand. The soil’s ability to absorb water must be considered when irrigating. If irrigation is increased beyond what can be absorbed, then the water becomes ineffective and simply runs off. This can become costly for property owners that are paying for irrigation water.
Soil Composition & Water
The type of soil that makes up your landscape will determine how much water it can absorb. For example, soils that are rich in clay are capable of taking in one to two tenth of an inch of water per hour. Meanwhile, more sandy soils can absorb as much as half an inch per hour.
If you are unsure of your soil type do the following:
- Select an area in the yard.
- Place a tuna can or other catchment device in the irrigated area.
- Run the irrigation system or hose end sprinkler until run off is observed.
- Use the water collected in the tuna can to determine how much water is delivered before run off occurs.
Cycle & Soak – Controllers
Many irrigation controllers have a built in feature called “cycle & soak”. By activating this feature the irrigation system will deliver a precise amount of water based on the soils ability to take on water. Once that amount of water is delivered and the soil can no longer take on water, the system will move to the next zone. At the conclusion of the cycle the system will go back to those zones with time remaining to deliver remaining water once the first amount has had time to soak in.
Cycle & Soak – Manually
If you are using a hose end sprinkler the same concept can be applied by manually moving your sprinkler. For example, run a sprinkler in one spot until the correct amount of water is applied. Then move to another location on the property while giving water in the first area time to soak in. If the area is small enough to be covered by a single sprinkler setting, run the sprinkler to the desired amount then turn it off to allow water to soak in (at least one hour) before the second application.
Water Absorbtion – The Key
The key to cycle & soak is to understand how much water your soil can absorb per hour. Anytime an irrigation or watering event requires more water to be delivered than the soil can absorb at one time “cycle & soak” should be used. When less water is required, such as spring and fall (in northern climates), cycle & soak may not be necessary. In fact when less water is being applied cycle and soak can actually have a negative effect. In these cases water can be trapped in the thatch and mulch layers of the landscape and not become available to the plants root system.
If you have any questions on your soil and its ability to take in water contact your Mainscape team member for an on site evaluation.
Additionally, stay tuned for next months issue which will address the often asked question of how often to irrigate.
Jeff Snyder
Director of Irrigation
and Water Management
