Harmony Horticulture

This article was recently featured in the ALCA Influence magazine September/October 2009

How often do you come across that perfect lawn, free of brown spots with the ideal shade of green that makes you wonder why all your properties can’t look that good? That perfectly green turf is hard to come by, especially with all the seasonal changes we have in the southern Arizona climate. If bewildered by that brown patch that just won’t go away no matter what you do, here are a few places to start when troubleshooting a turf problem.
First, you must ask yourself a long list of questions. What changes have recently occurred? Has this problem been present longer than one season? Have the environmental factors been consistent? Look at weather changes and see if there are any parallels in when your turf problem was first seen. Did you adjust and re-adjust your irrigation to accommodate for these weather changes? Many times, turf issues can arise not just from changes in the weather, but also environmental factors we can control, which brings us to the most important question: Did you check the irrigation? Did you re-check the irrigation? Are you confident the irrigation is not the issue? Making sure your turf has the appropriate amount of water seems to be one of our biggest challenges.
If irrigation has been confirmed, we can begin to look at other cultural practices that might be impacting the turf. Is the mowing height appropriate for the variety of Turfgrass? Are my mower blades sharp? Are we regularly changing the mow pattern? Mowing in the same direction overtime can begin to cause soil compaction and create ridges in the turf. If you are able to confirm that some of these cultural practices are not causing your turf issues, you can remove them from your ‘possible causes’ list.
Fertilizers and chemical applications should also be considered. Turf burn is often obvious, but what about that green stripe that stretches down the length of the grass? Is it from a faulty spreader or did the applicator not have it on the correct setting? Did we use a homogenous fertilizer or is it a blended material? Blended fertilizers will often distribute differently when broadcast. Larger particles throw further from the spreader and smaller particles stay closer to the spreader. Using homogenous fertilizers, calibrating your spreader and broadcasting multiple directions can help prevent striping in turf.
Did I use the right herbicide? One chemical issue that is often seen comes from using the incorrect Preemergent herbicide in turf. When managing weed infestations, it is usually recommended for both pre and postemergent herbicides to be used. However, if the goal is to control summer weeds and root-inhibiting preemergents are used, it might be discovered that the Bermudagrass has a hard time tacking down in the treated soil. You might find stolons traveling over top of the soil, but they are unable to connect to the soil and root due to the preemergent barrier used to control weeds. Using shoot-inhibiting preemergents will solve this issue. Again, asking if and when if chemicals have been used will help you discover what is potentially causing this turf issue.
When all abiotic (non-living) factors have been isolated, then we can lean towards the biotic (living) factors that might be causing our turf issue.
As interesting and exciting as “my turf has a fungus” sounds, in our area it just isn’t that common. Sure, we have a handful of pathogens that can plague our turf but they just aren’t seen frequently enough to consider before looking at abiotic causes first. Warm, moist conditions can help mushrooms to surface, often making us think that the turf is being affected by a ‘fungus’. Mushrooms found in patterns can indicate Fairy Ring, but not always. Dig around a bit more and confirm that there is in fact a pathogen present. It is also helpful to get an expert opinion or send a sample to the lab for confirmation before treating with a fungicide that may or may not control that particular pest.
In addition to the few turf pathogens, we also can come across pests that cause turf damage. One of the biggest pests often overlooked is rabbits. They mow down turf in circular patterns, are rarely seen during maintenance hours, and leave behind dropping that are only found when the ground is closely inspected. These patterns can be mistaken for irrigation issues, grubs or pearl scale due to the patterns and it seems the grass will never grow in those areas. Look closely for dropping and see if in fact they are present in the bare areas. Insects like pearl scale, grubs and sod webworms can also cause problem in Arizona turf. Pull back the soil and inspect in the trouble areas to if any of these pests are present.
After exploring potential biotic and abiotic causes of your turf issue and still no success, review your turf fertility program and make sure mineral and salt levels are acceptable for the type of turf you are growing. The key to any plant problem diagnosis is asking lots of questions, discovering the answer and isolating what the issue is not caused by, then moving on to the next potential causal agent. If an issue is occurring on your property, it is likely happening on another property. Call me to see if I can help solve what’s plaguing your Turfgrass.

As the summer is quickly coming to a close (though not quick enough) we will all be thinking about getting ready to overseed our turf. Just as the Bermudagrass is just starting to look its bests around the middle of August, we begin dropping our mow heights to begin preparing to throw Ryegrass seed around the beginning of October. This can be a very successful process, or it can be a disastrous one that you will pay for the following 3-4 months. Blame it on the weather ‘these 100+ degree days zapped all my seed!’ or blame it on the seed ‘my germination rate was very low this year, it must be bad seed!’ Whatever you decide to blame it on, here are a few keys that will be helpful in overseeding success.

• Check all nozzles before overseeding, just after dropping to your final mow height. Mowing to ½” can sometimes displace your spray head or cause problems. If these problems are fixed after the seed is down, you may run into problems like seed washing away if sprinkler head repairs are required and flooding occurs.
• DO NOT scalp! True scalping of turf is not recommended because of a few reasons:
• Can cause excessive damage to Bermudagrass, delaying its appearance next season
• Scalping stresses out the turf, increasing the risk of disease and insect infestations
• Seed can more easily dry out because there is less moisture- holding thatch and organic matter
• Make sure mower blades are sharpened or replaced just prior to dropping mow height
• When dropping mow heights, ONLY REDUCE HEIGHT BY 30% PER WEEK
• You may have to begin dropping your height at the end of August to safely drop it to ¼- ¾” depending on Bermudagrass variety
• Consider leaving some clippings behind as they will act as a mulch protecting seed from drying out (leaving clippings behind will not cause thatch issues)
• Rechecking irrigation daily at different times of day for 1 week after seed has been thrown
• Irrigation is often the reason for spotty germination or seedling failure, check and recheck often!
• Calibrate your spreader and confirm your square footage
• Too little seed will be sparse and won’t look good until spring, too much seed can choke out each killing seed
• Begin fertilizing within 2-3 weeks of overseeding, continuing to apply fertilizer every 4-6 weeks through the winter and spring
• For recommendations on the ideal fertilizer formulations and fertility programs, please give me a call

It is best to wait to overseed until nighttime temperatures are in the mid 50’s or low 60’s. Depending on weather and other environmental factors, you will likely have your first mow about three weeks after seeding or when seedlings are about 3” tall. Good luck out there, and remember cool weather is coming; it may just be November before we see it!