Turf Rant: Believe Me, It Is An Irrigation Problem!

Tony Koski, Extension Turf Specialist

The home owner insisted they were "watering enough". Clearly

they are not!

In case you missed my last blog on brown spots in the lawn and Ascochyta a few weeks ago, well, it’s still a problem. If you are seeing these symptoms in your lawn: it’s an irrigation problem. Yes, it’s water! Even if you don’t believe me – and most people (professional turf managers and home owners alike) don’t – trust me, it really, REALLY is an irrigation problem. Repeat after me...

There is an irrigation head in the middle of
that green spot - which is in the middle of that
huge brown spot. Hmmmm...could this be
an irrigation problem?

There is the head...way down in the turf.

Poor head-to-head coverage, heads that aren’t level, heads that are too deep, heads that aren’t turning or are plugged, “shadows” created by trees, shrubs, perennials and other obstructing plants in your landscape. There are so many potential causes of poor water distribution, problems that are magnified when we have hot weather and it doesn’t rain for 1-2 weeks. We have seen every conceivable cause of poor irrigation coverage in the past month, after being reassured by the client that “it can’t be water… it has to be something else”. Well, we were correct and they were wrong. Yes, this is turning into a bit of a rant…intentionally!

Yes, it kinda sorta still works. Water comes out,
but not nearly enough to reach adjacent heads.

Just because "this has never happened until this year" (though it probably did)….or you are watering “enough” or “more than I used to” (maybe, maybe not)…. or “it looks like water is going everywhere” (yes, but not evenly)… or “it’s a new irrigation system” (sorry, no guarantees of anything there)… or yada yada yada…. Well, hopefully you get the gist? If you are seeing spots like this in your lawn (especially if there is a bright green spot in the middle of it, or next to it), it’s a water problem.

Conduct your own informal irrigation audit
by placing containers in your lawn (on the
brown and green spots); collect water for an
entire run time and compare depths.

If you still don’t believe me, place identical containers (Tupperware, pint Mason jars, empty yogurt containers or cat food cans, drinking cups that won’t tip over) on the healthy, green areas of your lawn AND on the not-so-good brown areas the evening before your system is set to irrigate the lawn. In the morning, measure the depth of water in the containers. The depth of water on the brown areas will be less than on the green, healthy turf (that’s a promise). It might only be a difference of 0.1 or 0.2 inches, but that difference in water adds up quickly under summer growing conditions. Those parts of the lawn receiving less water become drought- and heat-stressed sooner and more severely than the adequately watered parts of the lawn. The stressed areas are more susceptible to Ascochyta leaf blight, which turns the grass brown (but doesn’t kill it) – or the grass might just begin going dormant (= brown!).

Your job is then to figure out WHY the coverage is lacking on the stressed areas (station run time, sprinkler spacing, pressure, heads that are broken or plugged or obstructed or too deep, etc.) and remedy the problem. If you can’t figure it out or don’t have the expertise, hire someone who understands irrigation systems to help you. Once fixed, the grass can recover remarkably quickly – but that will depend on how long you have waited to do something about it.

Ascochyta outbreak on 9 June 2016 in Windsor

Turf can recover relatively quickly after the irrigation persoalan is resolved. This photo taken 2 weeks later (23 June 2016)

Looks even better after another week of recovery! (29 June 2016)

Avoid the temptation to turn your lawn into a rice paddy to speed recovery of the brown areas. Soggy conditions can actually slow down recovery. Simply maintain adequate – but not soggy, mushy, swampy – soil moisture. And hope that the monsoon rains begin soon - here: http://www.extension.colostate.edu/lawncheck/book.shtml