Q. We can’t figure out what the problem is in our grass and hope you can help. Last year it (the lawn) was just beautiful but we have these dead kinda like circles. What can we do to make it better? We have a Rain Bird sprinkler system. – L.J., Albuquerque
A. “Dead kinda circles” huh? The first thought I have would be that there is a fungus among us.
In order to diagnose, get down at ground level and along the “rim” of the circle see if you can find blades of grass that are horizontally marked or scarred. If it is a fungus, the blade will be green nearer the base (ground level), then do a color change showing yellow at the tip of the blade.
We used to ask nursery clients to bring a chunked-out 12-by-12 inch piece of the turf exampling both the healthy lawn and the ill turf. Rather like digging up a small piece of sod, if you will. Then, post- diagnosis you can set the chunk back into the lawn and it should reconnect with little trauma.
What we looked for was at the “rim,” where the blades looked good turning into sad. That’s where you could usually find the telltale signs of a fungus infection. To me, that’s the look I’m seeing in your photo, a fungal infection.
If it is fungus, there are ready-to-use sprays that attach to a garden hose covering up to 5,000 square feet for “cool season” turf (blue grass or fescue) or 2,500 square feet if you’re growing warm season turf (Bermuda, buffalo or blue grama) Although you didn’t say, your lawn looks like fescue, so it’s a cool season turf.
You can find ready-to-use spray fungicides at most garden centers or nurseries. If you’re taking a sample to a nursery for diagnosis, don’t go traipsing through the grounds with a tray of “diseased turf” – ask a professional to come to the car to look – unless you’re invited in with your sample.
Now you’re wondering, how did my beautiful lawn get such a malady? The causes are varied but here’s a few to think about.
First is the heat. You’re growing (I think) a cool season turf which tends to “sit still” and not grow vigorously in really hot periods, and remember how wicked hot it was in June? Ugh! Maybe you fertilized, expecting it to grow rapidly, and it couldn’t, so it got stressed. It’s a perfect invitation for fungal infections.
Next, do you clean the under deck of your lawn mower or if you have a service come, do the mowing do they wash the under deck before tending to your lawn? If there was the slightest fungus allowed to collect and then the lawn was mowed, the infection could be spread that way. In other words, wash the under deck of your mower after each mowing. If you’re using a service, ask to peek at the machine. You’re paying for the service, so make sure the equipment is properly cared for.
While you’re looking at the mower, is the blade sharp? A dull mower blade literally tears the blade rather than cutting it, so that ragged end becomes a place of stress, again inviting infection. Sharpen the mower blade.
Next is the watering. The watering need be done very early in the morning. That way the blades have been filled and are plump, ready to deal with the day’s weather. If you are watering in the evening, the area stays cooler naturally and again that environment is a great invitation for fungus to settle, grow and spread.
Water early in the day and make sure to not water during the heat of the day or you’ll be wasting so much water. With your watering system, are you confident that all of the sprayers are functioning properly?
You can do what I call a “tuna can test.” Set several shallow cans, all the same size (tuna or cat food works great) out all over the lawn and run the system. Do all the cans contain equal amounts of water? If not, adjustments might be called for to assure the lawn is getting all the water it needs and you’re offering. With the minerals in our water, it’s easy for a spigot to get plugged.
Also, are you fertilizing too often? We tend to expect great things when we fertilize, but done too often the turf might be over-stimulated, again causing stress. But the exact opposite could also be true, too. Perhaps you haven’t fertilized and the turf got hungry, again causing stress. It was so dreadfully hot recently that not fertilizing, I think, is a good thing, but as we cool a smidgen perhaps a fertilization is in order.
You don’t want to do too many processes to the lawn all at the same time.
If you diagnosis the lawn as having a fungal infection, please wait a week or two if you feel the need to fertilize. Or vice versa. Fertilize to see if a feeding could be just the kick in the pants the lawn needs to regroup and be beautiful again.
Checking to see if the lawn does have a fungal infection, then treating, making sure it’s getting enough water and if necessary fertilize, the lawn could make a good come back, especially as the season advances.
Happy Diggin’ In.
Tracey Fitzgibbon is a certified nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, NM 87109, or to firstname.lastname@example.org.