Irrigation can often be a point of contention with a lawn service. We don't think it has to be. To get to the bottom of the irrigation issue it is important not only to check system coverage but also know your weather conditions and the value of natural rainfall.
If it does not rain for one full hour, you should still irrigate. Without doubt, accounting for rain is the most difficult part of deciding how often to water your lawn. A good quality irrigation should be in the morning for 45 minutes to one hour each zone. The goal should be 3/4" to 1" of water uniformly across all turf areas. Current watering guidelines allow homeowners to water twice a week. We recommend taking full advantage of both irrigations during the hottest months of summer. Let's take a look at this month's rainfall to date at Julington Creek, the 32259 zip code, to illustrate how difficult determining when to irrigate can be:
Week one: It rained twice. Monday's rainfall was 1/4". This was not enough to account for an irrigation. Short, heavy, rainfall can often have a negative effect on turf. Roots will grow towards the water to soak up as much as possible in order to survive. Over time, without proper irrigation practices roots will shorten, causing the turf to look yellow and be susceptible to nematodes, fungus, insects, and drought. The next rain was Friday. Fridays rain was heavy and put out between 3/4" and 1". If your irrigation was scheduled to run on Friday, it would be ok to skip this irrigation.
Week two. Week two was interesting. It rained 6/7 days, however, only once day did it run long enough to warrant skipping an irrigation. The other 5 days of rain can have a negative effect on the turf if proper watering practices were not observed due to rain.
Week 3: No rain at all. It is critical to water properly and uniformly. In a week with no rain, weakness in your irrigation coverage can more clearly be seen. If one area of your yard is not as green as another it is a good idea to check to make sure you are getting the full 3/4" to 1" per irrigation. Putting out less than that can cause shorter roots, yellow turf, and attract insects.
In summary, It has rained ten times so far in the month of June. Only 2 of those rainfalls have had a positive effect on the turf. Proper watering can be very complicated. Looking backwards at the rainfall is the only way to make the right determination for your yard going forward. A good rule of thumb is if it does not rain for one full hour you should still irrigate.