Talking Trees with Davey Tree

How to Get the Best Lawn - Irrigation, Grass Species, and More PART 2

July 08, 2021 The Davey Tree Expert Company Season 1 Episode 26
Talking Trees with Davey Tree
How to Get the Best Lawn - Irrigation, Grass Species, and More PART 2
Show Notes Transcript

Zane Raudenbush, turf and herbicide specialist within the Davey Institute, talks all about how to get the best lawn to celebrate Smart Irrigation month this July. In part two, Zane talks about what the proper height your lawn should be depending on where you live, fertilization and aeration, and how to use the right lawn tools the right way.

In this episode we cover:

  • Soil (0:53)
    • Top dressing (2:21)
  • Proper height (4:17)
  • Using the right tools the right way (7:48)
  • Sharpening your blades (9:53)
  • Fertilization (14:03)
  • Aeration (20:39)

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Doug Oster: Welcome to the Davey Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each episode showcases one of Davey's certified arborists sharing advice with everyone about caring for your trees and landscapes. We'll talk about everything from introduced pests, seasonal tree care, deer damage, how to make your trees thrive, and much, much more. Tune in every Thursday to learn more because here at the Talking Trees podcast, we know trees are the answer.

Welcome back to what I'm calling Lana [unintelligible 00:00:33]. Everything you need to know about growing a great lawn with Zane Raudenbush, turfgrass, and underside specialists from the Davey Tree Expert Company. Now in part one, we covered watering, choosing the right grass, and more for part two, I'm picking it up with the importance of good soil. In the case of a new lawn that's been put in where they have this awful soil, and I see this as often as you do, from your standpoint, what is the solution? Do you have to start new or do you start improving the soil? What's the key there?

Zane Raudenbush: That's a great question, Doug. That's a bit of a loaded question because even myself, this is something I have quickly-- There's a real interest in our company to come up with services that remediate that because ultimately, the quality will continue to suffer, that we are not going to be able to get the quality up until that piece is addressed, that the soil's addressed. How do we go about that? That probably depends on what we might see. We first pull a soil test, determine what it is that we working with, to get the physical properties and the chemical properties of the soil.

From there, we might be able to just modify it through the use of like top dressing material, top dressing some type of compost, a compost biochar material. Sometimes it needs to be more aggressive than that. We would maybe see that there are places where you actually should come in and introduce a significant amount of material, work that into the soil. I would do that as a very last case scenario. One, I'm not a huge proponent of coming in, and disturbing the soil, totally disturbs the weed seed bank. You can end up with a lot of issues thereafter.

The immediate would be to begin coming in and top dressing. That's where we spread a layer, a quarter to half-inch of material of some type of rich organic material. It could be, and this is where we're talking about where we're going to source that material. Over time, that's going to build up the organic matter in the soil and help to sustain better plant material. Yes, it's a real challenge to have a conversation with a customer to explain that, "I'm really sorry, but your soil here is really is poor. Unfortunately, we aren't miracle workers. We will never be able to grow really thick turf in an area like this, just simply because it's cement," in the summer months that sub-soil literally sets up like cement.

Doug: I don't care how much water you pour on there, or how much fertilizer you pour on there, without that, the basis of what that plant needs underneath there, you're fighting a losing battle there.

Zane: Yes, you're spot on, Doug. I've been doing this for a long time, but you always come back to those basic fundamentals of soil species, sunlight and if the soil piece isn't correct, it's a real challenge. I actually find a lot of times, it's the most easily overlooked. I get my soil probe out and we start going along, going through yards and I'm pulling soil samples and showing them that, they maybe only have a half-inch of dark top soil and the rest of it is a heavy, blue clay.

All of a sudden the light bulbs go off and feel like, "Wow, I never thought about that," out of sight and mind. We're all susceptible to that in all parts of our life, with other things. Yes, you cannot, you cannot underestimate the importance of quality soil as it relates to rearing particularly turf grass plants.

Doug: You talked about cutting the grass, what is the proper height and why does that matter?

Zane: Great question. The height of cut is not a stagnant thing. What you start at is a height of cut in the spring is not what you will be at in the middle of summer and what you'll be at in the fall. As a general theme, Doug, we can't get our customers to mow the yards high enough. You'd be blown away by what a benefit in the summer months there is to raising the mowing height somewhere between three to four inches for most of our cool-season grass. In the summer months, if you haven't done it already, take the mower up a notch or two.

One, you'll see that you can often reduce the frequency of mowing through that piece in the summer months that, we just don't need to mow as frequently during the summer because the growth isn't there, but why is that beneficial? We have more leaf area to capture sunlight. That's where the plant's making its food. You have to picture sunlight as being absorbed through the leaf tissue, in that leaf tissue, they're converting that sunlight through the splitting of water to make sugars. If you have a really finite amount of leaf tissue, you can can only make so much sugars.

By increasing the mowing height, you increase the area with which sunlight can be absorbed by the plant to make sugars. It just creates an overall healthier plant system. It's been a well-studied, well-documented thing that it's one of the most basic cultural practices that you learn in any turf grass science class when as a general rule of thumb, when turf grass plants get stressed, increasing the mowing height is one of the first steps. Doesn't matter if it's on a golf course, butting green, a sports field, a home lawn, that when plants get stressed, a general rule of thumb is if you increase the mowing height, you'll see some reduction typically in that stress.

What is the ideal of mowing height in the summer months? Three to four inches. Then another thing that I see is in the spring is the mowing frequency. Mowing frequency is not a stagnant piece either. Many of us have learned, unfortunately, that if you're going to stick to the once-a-week mowing frequency in the spring, you'll be bailing hay. In the summer months, you're actually overstressing the lawn. Mowing frequency is another thing that can shift. In the spring months, you really would be doing your lawn a favor if you could mow it every four to five days, it'll increase the density, it'll decrease the leaf texture, make a finer leaf texture. I hope that answered your questions.

In general, what should the mowing height be in the summer months? You should be raising your mowing height somewhere between that three to four inches and then in the spring and the fall, staying closer to that three-inch mark. I don't see any real reason to go below three inches unless there is a reason that you really like that look. Sometimes, the warm season grasses, Bermuda grass, Zoysia grass, they like to be more shorter. If you're somebody from the south who has moved up to the Pittsburgh, Ohio, Pennsyl, in this area, don't mow your grass at the same height you did when you lived down in North Carolina because you'll see that it's just, it's really tough on our cool-season grasses.

Doug: Then, talk a little bit about the importance of the right tool, a sharp mowing blade when you're cutting, right?

Zane: Yes, yes. Mowing is a stress. You are wounding the plant. I always talked when I worked as a professor at Ohio State, I always told my students, "If you were going in for knee surgery, do you want the surgeon to have a brand new sharp scalpel or one that's done 500 patients before you?" I know that's a bit of a crude analogy, but the reality is you want a nice sharp blade to be able to make a crisp cut. Otherwise, as you wound the plant, you expose more leaf tissue, it takes longer for that plant to repair itself.

If you look across to your yard and you see that has a white tinge to it, and if you look closer at the leaves, you see like a stringiness off the tips, that's a great indication that you may need to sharpen your blade. Another thing I see, Doug, is that these mowers, the decks are designed to create vacuum. In the deck, they're creating a vacuum to pull the leaf, to keep the leaf upright so we're not blowing it down and I'm guilty of it too. If you don't have a deck that's nice and clean, it's very common to not get the proper vacuum. You're also not going to get a really great cut as well.

Making sure that the deck is clean and blades are sharp. Right now, if we've all had mowers that were serviced in the winter, had sharp blades coming out of spring and you haven't sharpened your blade yet, flip them all over, take a look. There's a good chance that it needs sharpening right now. This would be a great time to do it. As those plants are stressed, get a nice sharp blade back on there. You'd be impressed the difference in quality. We have some great photos, Doug showing, areas managed with dull blades versus sharp blades. It's a staunch difference. It's unbelievable.

Doug: In my case, all I'm doing is I remove that blade and I take it to the hardware store. I guess, in your case, being this turf expert, you know how to sharpen this blade yourself. Is that right?

Zane: Yes, yes. For me, I take my blade off myself and make sure that you practice some good procedures there. When you tip your mower up, I always like to tip my mower so that the carburetor is on the upside. Typically, if you look where your air filter is, you'll want that to be facing the sky so that doesn't fill up with fuel. Then I also pull off my spark plug wire to make sure that for whatever reason, if we wouldn't cause any ignition there, I remove the blade, and then a few things you want to do is use that blade is going to be covered in decayed caked-on grass.

Get a wire, brush out, and clean it off and inspect it. You want to make sure that there are no hairline cracks in the blade, and then lay it on a flat surface. [unintelligible 00:10:52] blade should be nice and flat. It shouldn't be bowed. It shouldn't be bent in any way. Then you'll begin to put a new edge on it. There are different tools. If you do this somewhat regularly, you can use a file. Unfortunately, I know I'm a victim of this too. My blades get sharpened about three times a year. They probably could use more than that. I use the angle grinder, trying to maintain somewhere between about a 40 to 45-degree angle.

Sometimes I see people want to get a really thin, a really narrow-angle, 10, 15-degree angle, and it is razor-sharp. The issue with that is there's no material at that edge to maintain an edge. While it may be sharp, it's not going to maintain that edge for very long. You want to keep the proper angle and there are little bits that you can buy that go on the end of a drill to help maintain that proper angle.

Once you've sharpened it, you've got a good edge, then I like to balance it. You'd not like to. You want to balance the blade. The easiest way to do that is to just drive a nail into a stud and then hang your blade on that nail. You'll see that the blade will just like a balance, the heavy side is going to flip to the bottom and then you'll just want to take more material off that side until it's balanced.

Doug: Let me explain that then. We're not talking like putting it flat like a turntable like for a [unintelligible 00:12:18].

Zane: Yes, sorry.

Doug: We're hanging it like how would you say like [unintelligible 00:12:23]?

Zane: If you are going to hang your coat on a coat rack, that nail is driven into the wall, and then you're going to hang your blade up on the wall and it should have the ability to rotate around. The speed with which it drops give you an idea of how much material takes off. Again, these are the kind of things that if you don't do them, if you haven't done that before, don't lose a bunch of sleep over it but next time you do, check the balance because if you end up-- Let's just say that you hit something with that blade and took a big nick out of it and you had to grind away a bunch of material on that side of the blade to reestablish that edge, you'll see that you've really changed the balance of the blade.

Doug: I know.

Zane: That's going to put a lot of pressure on the main bearing and on the crank itself because it's going to be out of balance. You'll feel the vibration can just end up vibrating the mower apart, particularly really the case on like zero turn mowers or mowers that have multiple blades per deck, this is the kind of thing that burns the spindles up, et cetera.

Doug: I'm just taking mine to the hardware store, Zane. [laughs]

Zane: Well, you know what, and nothing wrong with that, Doug. I think it's one of those things that it's worth its money to just have it done. If you don't have the tools, you don't have the place to do it, take it off, let somebody who does it every day, sharpen it, and get it back to you, know that it was done right. Nothing wrong with that at all.

Doug: If you're one of those guys like me, it doesn't know what side of a hammer to hold, [laughs] you go to your local hardware store and they'll do everything for you.

Zane: Well, you've got the wherewithal to know where your limits are so I commend you for that.

Doug: Well, I want to keep going on turf and I want to talk about fertilization. What is your feeling about fertilization for a lawn? I know that this is going to be different for every situation, but in general, what are you thinking for fertilization for turf?

Zane: The fertilization thing is another one, lot like the irrigation, we want to give the plants just what they need and nothing more. There are logistical pieces to turfgrass fertilization that need to be considered. The ability to give the plants just what they need and nothing more might change the frequency with which things are done. We don't have the ability to be out there, every three to four weeks.

Oftentimes, we had to err on the side of using material that's slow-release, have to take advantage of the time that we won't be on the property. In general, if you could only fertilize one time a year, the ideal time would be in the fall. The fall is when we see there's a real-- The thing about the spring is those plants come out of dormancy, they can put more emphasis on shoot growth compared to root growth if they are over-fertilized.

One of the things that we sometimes see in the spring is if people over-fertilize the plant, it can all of a sudden start to allocate a lot of resources to putting off a lot of shoot growth, and very few resources allocated towards root growth. We actually end up with a plant with a stunted root system, in the middle of summer, if people over-fertilize. In the spring, you might see, like for our company, we actually use less nitrogen in the spring.

We're not trying to stimulate a bunch of shoot growth. We're often trying to get your crabgrass pre-emergent out there at that time, and we're trying to put the potassium out there at that time to help the plant through drought stress periods, whatever might be. You do have to be careful. To come back to your question, fall is a great time. If you're going to only do it one time, it would be in the fall. Our programs are typically going to give you somewhere between four to six fertilizations per year, depending on where you're at. That's the idea of what we would call spoon-feeding.

Instead of having to over apply to make up for the fact that you won't be there frequently, we come back and spoon-feed time and time and time again. The benefit of that is that we're not having to oversupply the plant and overstimulate growth because we're going to come back to that property relatively frequently and just give this spoon-feeding approach. The ideal scenario, I would say, would be four to five fertilizations per year, but you'll also see, depending on the material you use, you could get away with far less. That's where I'm trying to get my lawn too is, fall and spring fertilization and that will be all I do.

Doug: Well, I see a lot of this early in the season where people are pouring on way too much nitrogen onto their grass. Yes, they want that green, green, green grass but as you said, that can lead to a lot of problems. That soft, new growth.

Zane: Succulent.

Doug: Yes. You then you don't want this stuff going into the storm sewer. Just use what you need. Two pounds is recommended. That doesn't mean put four pounds on to make it super green, right?

Zane: Yes, more is not better for sure. You brought up a great thing about the storm sewer and this is something that we all need to take a close look at. The reality is when you apply granular fertilizer, you cannot keep it from getting on impervious surfaces. I don't care how good you are, what kind of shrouding you might have on machines. We get material that goes on impervious surfaces, and there's a real easy way to fix that is to go blow it off or sweep it off.

As a best practice, particularly along the roadside curbing where that material, we know where it will end up. It has no other place to go but the storm sewer. When you're done, if you have a blower, go out and just blow that material up over the curb, trust me, it hops over the curb, and get it back onto your lawn because one of the best things we know about turfgrass, is they are phenomenal. If material is deposited on a turfgrass, then it doesn't leave.

That is from an ecosystem services standpoint, the ability of turfgrasses to reduce sheet flow and keep stormwater nutrients and things on the property is one of their greatest assets. If you can get that fertilizer back into the turfgrass canopy, it won't go anywhere, it won't make its way into our stormwater systems. To your point, Doug, I was trying to give the plants what they need. I don't want to get lost in the weeds about rates and sources and I could and that is a whole nother conversation we could save for another day.

Again, just like the irrigation, you can put more down. If you overdo it, you can create a lot of problems for yourself and you might deal with those problems for the whole remainder of that season. Just a really well-balanced, well-timed nutrition plan of a fertilization you should see a small stimulation and growth and enhancement and color. Eventually, that will begin to Peter out and that's when it oftentimes makes sense to come back. Now in the summer months, the reduction in color, the reduction in growth typically is not because nutrients are limited. It's a result of the heat and the lack of water. That is not a time to maybe go back out and think that fertilization is going to solve your problems when that's not the limiting factor. The spring and the fall or when the lawns are peaking, the summer months, we are in maintain mode. Summer is all about trying to maintain what you have to think that you're often going to improve quality in the summer months. There are other resources outside of all of our control, heat, sunlight and water. We just simply can't control that often are what ultimately, influence turfgrass quality.

Doug: One more thing, how about aeration? Is that something I should be doing, and what is it?

Zane: Yes. There are different types of aeration. The one that's going to be most common in a home lawn would be what we call holotype aerification, where you use a machine that comes in and pushes a probe down into the soil and ejects out a core of soil. That has several benefits. It can improve the infiltration so there's water. We get precipitation, those holes are going to create direct channels down to the soil to help water move through the soil. It's also relieving compaction. You have to picture that as we begin to walk on these surfaces, we are compressing the soil.

Soil is complicated, particularly clay particles, which are these flat flake-like particles. You can start to actually compress them and create cement. We talked about the gate example, Doug, where if people can't grow grass around their gates, and I went on to the thatch piece, but really, that's more related to compaction. Anytime that you get the traffic concentrated, you will see that you're compressing the soil. One of the things about the soils where we live, that have relatively higher amounts of finer particles like clay, is there are what are known as cohesive soils. A cohesive soil by definition is its ability to resist compaction is related to the soil moisture.

A cohesive soil [unintelligible 00:22:24], an example of this would be like a high school football field. If you've ever been out and watched the high school football field on a nice day, they play with no issues, but all it takes is one game played during wet conditions and the field can be destroyed, because it's compaction resistance is related to soil moisture. As the moisture goes up, it's more susceptible to compaction, and so on our home lawns and things like that. I'm out my yard every day. It doesn't matter if it rained or not. We are compressing the soil and compacting it, and so aerification comes in and ejects out a channel and allows that soil to begin to decompress.

If you're going to rent one of these machines, as a homeowner, when you have gates, maybe you run that machine over your entire yard one time, but the areas where you know that there would be compaction high traffic, run that machine over at two, three, four times, because those are going to receive a greater amount of compaction. Back to your question, what does it do? It increases infiltration, it relieves compaction, it also improves gas exchange, so when you think about the soil, a volume of soil is 50% soil particles, and another 50% is pore space, and that pore space should be about half water, half air.

We're just trying to improve gas exchange, and there's tremendous benefits. A lot of things about turfgrass management, Doug, are these are long term decisions. You are making decisions for the long term benefit of the stand. Fertilization is an instant, you fertilize it, it grows, it gets color, but compaction, over thatch production, these are silent long term killers, and so soil modification, aerification, interceding so the introduction of truly superior plant material. It might take five years to really modify and make a significant modification to the stem, but every year, you're introducing 15% of that better plant material, another 15% the next year, another 15%.

Over five years, you've completely modified the composition of that turfgrass stand. This is where, for the people listening today, services like that, you are hedging your bet that over time, several years of those type of things, you are truly creating a much better surface to grow plant material. Just because you aerified your yard one time doesn't necessarily mean that that was enough or that you're going to get all the benefits that could be there. It really is a long term process.

Doug, could you ever go long aerifying your yard? No, I think it's a great tool. Is it one that I would do in the summer months? No. The ideal time to do it would be sometime after rainfall. If you're going to rent one of these machines, and it's dry, you want to irrigate the turf, because you cannot get one of those times down more than a half to an inch when the soil is really hard, and so irrigate, give it a good irrigation a day or two before, and it will help to loosen the soil, and you'll pull a much deeper core, and you'll get more compaction relief.

Doug: All right, Zane. I'm going to leave it right there. I kept you a lot longer than I told you I was going to keep you. This is great stuff and great information for homeowners to have a great lawn. I just appreciate your time. We could talk I think for another hour about turfgrass.

Zane: Yes. We definitely could, and I hope you have me back some time. I'm passionate about this stuff. There's just so many benefits, Doug, to having a great property that you're proud of, and from a monetary standpoint and emotional standpoint, it's all good.

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Doug: All right, Zane. Thanks again.

Zane: Yes, have a good day.

Doug: Tune in every Thursday to the Talking Trees Podcast from the Davey Tree Expert Company. I'm your host, Doug Oster. Next week, we have a fascinating conversation about climate change and trees with Dan Herms. I know you'll enjoy this discussion. As always, we'd like to remind you on the Talking Trees Podcast, trees are the answer.

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