Tips for a Proper Irrigation

With the arrival of summer, we have moved out of our rather wet spring and into the typical cycle of long hot days. By employing proper techniques to irrigate your lawn while being conservation-minded, you can easily implement an appropriate and cost-effective irrigation plan.

How Much, How Often, and What Time of Day?
These are the most common questions that face property owners and managers and the simple answer is, “it depends.” This is because the needs of your property will always vary from other properties. There are a few key components to assessing the best practices for irrigating your turf and they are comprised of the following:

1. What is the depth of my root zone?
2. What type of soil is present? (sandy vs. clay-based)
3. What variety of grass is present?
4. How much sun does my turf get (full sun vs. partly to mostly shady)
5. What are the wind conditions of my property? (sheltered vs. exposed to wind)
6. What are the weather conditions?
7. What is the “flow-rate” or watering output rate of the irrigation that is present?
8. What time of day should watering occur?
9. How often should I water?
10. How should my grass be cut to compliment a proper irrigation program

                                                                                                                                                                           The Root Zone Depth is Critical to Know
To determine how much we will need to water, we have to determine how deep the root zone is for your turf. The reason for this is that you will need to supply enough water to seep to the bottom of this root zone as this is where your grass plants take-in water. Knowing whether your root zone is being adequately watered is the key to a proper irrigation program.
To determine the root-zone depth, the easiest method is to take a flat-headed shovel and dig down to pull open a space where you can see the base of the roots. The distance from the base of the roots to the crown of the plant (the part that breaks through the top of the soil) is considered your root zone depth. Proper irrigation requires your soil to contain moisture down to the base of the root zone.
What type of Soil is Present?
The type of soil that you have on your property determines the amount of water that is necessary on a recurring basis to support hydration of the root zone of growth. On average, clay based soils (appear orange-brown in color) need a larger amount of water to reach the root zone. Typically, this can be 1-1½ inches of water per iteration. Sandy soils (typically dark-gray in color) however, aren’t able to hold as much water as clay-based soils and therefore need less water to reach the root zone, generally about ½ inch of water is adequate.
To truly determine how much of your irrigation is reaching the root zone, it is best to check the amount of percolation subsequent to a watering cycle. If you find that the soil beyond the root zone has been saturated, you may reduce the amount of irrigation being applied, conversely a dry root zone means that irrigation should be increased.
The second important aspect of soil type to be aware of is the fact that clay-based soils will typically need less frequent watering than sandy soils as they tend to be better at retaining water. Again, checking the moisture level of the root zone will let you determine if your irrigation program is adequate.
Weather Conditions are the Driving Force behind the Need for Irrigation
Most towns in New Jersey require the presence of a working rain sensor on your irrigation system. This is because it is wasteful to water your lawn during times when it is not necessary and over-watering your lawn can create unnecessary runoff which poses a threat hazard to streams and bodies of water in the state. Although many irrigation system controllers have a setting to bypass the rain sensor, there should never be a reason to utilize this setting unless system maintenance or testing is being performed.
During times of frequent rainfall, there should be no need to irrigate your property. However, during times of relative drought, periodic deep-watering may be necessary to maintain turf health and optimal growth rates.
What is the ‘Flow Rate’ of my Irrigation System?
To determine how much water your irrigation system puts onto your lawn during an irrigation cycle, you should place a rain gauge or drinking glass inside of the irrigation zone and allow it to accumulate water from the sprinklers for one cycle of your irrigation system. Once the cycle is complete, measure the amount of water inside of the container. On average, 1 to 1 ½ inches of water are necessary to moisten soil to a depth of six inches. Again, this will change given the variables of soil type from clay to sandy.
What Time of Day Should Watering Occur?
The simple answer is the average time of day when evaporation is least likely to be a factor. For most areas, this would be during the hours of darkness when winds are most calm. It is recommended that watering occur, on average, between the hours of 10:00 pm and 5:00 am. Watering in the middle of the day is a needless waste as the vast majority of the water sprayed from your irrigation system will evaporate before it ever penetrates to the soil.
How Often Should I Water?
Again, there are variables at play here that drive an appropriate answer to this question. The average answer would be that your turf should be watered properly at least twice during a seven day week. You may, however, need to water more often if your soil is sandy or if there is a hot and dry weather pattern present.