Since plants can be as much as 85% water, having an irrigation system can be very helpful in promoting and maintaining healthy plants . . . especially turf. Unfortunately, most irrigation manufacturers and installers do not know how to properly water plants resulting in systems which create more problems for the turf and plant health care professional including:
- Shallow / Reverse Rooting
- Soil Compaction
- Wet / Dry Spots
- Thatch Build-up
- Thinning Turf
- Reduction of critical soil biology activity
- Increasing various disease and insect damage
These are all serious issues resulting in significantly higher costs to maintain turf and plants.
The Water Your Lawn Brochure provides guidance on “how much” and “when to water,” but the entire process must begin by knowing how much water is actually being sprayed out over a specific amount of time. Every system is different. In fact there can be significant flow differences from one zone to another. There are many reasons why this occurs starting with the fact that the water pressure varies from site to site, even if operating on public water. Within each system other variable include: pipe size and valve sizes; lengths of runs; numbers of heads on the zone; and the actual size of each spray head.
An irrigation consultant can conduct an “Irrigation Audit,” which can be costly, but you can DIY with a few straight-sided, large cans. Turn on the first zone to determine what area is being covered. Randomly place the cans within this area with one or two placed closer to the head, another one or two in the middle area and another one or two towards the outer perimeter. However, take care NOT to place any cans so close to an edge that it would catch the over-lapping spray pattern from the adjacent zone. Now re-start that zone and allow to run for exactly 15 minutes. Shut off the zone and measure the water in each can. Hopefully the amounts will be very
similar. If the cans have approximately ¼" of water then you know that zone must run for 1 hour to get 1" of water applied. If only ⅛" then that zone needs to run for 2 hours . . . and so on. Repeat this process for every zone.
Depending on the final timing required to achieve the desired 1" of water and trying to avoid have the lawn/soil wet all night, you may have to water every night but only 2-3 zones per night perhaps starting at 3 am and finishing by 6 am. As an example: Sunday zones 1-3; Monday zones 4-6 and so on.