How to Keep Your Lawn Healthy in the Summer PART 2

Zane Raudenbush, turf and herbicide specialist within the Davey Institute, talks about fertilization, soil and caring for drought stressed lawns.  

In this episode we cover:  

• Fertilization (0:33)  
• The difference between fall and spring fertilization (2:18)  
• Importance of a soil test (3:30)  
• Explanation and importance of PH (6:20)  
• How to deal with poor soil (8:20)  
• Growing grass in the shade (10:50)  
• Taking care of drought stressed lawns (13:00)  

To find your local Davey office, check out our find a local office page to search by zip code.

To learn more about fertilization, read our blog, Should I Fertilize Lawn in Fall? Yes! Here's Why & How.

To learn more about soil tests, read our blog, How to Perform a Soil Test (And Why You Need One!).  

To learn more about drought stressed lawns, read our blog, What Causes Brown Spots on Lawn? 

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Have topics you'd like us to cover on the podcast? Email us at podcasts@davey.com. We want to hear from you!

Transcript

Doug Oster: Welcome to the Davie Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each week, our expert arborists share advice on seasonal tree care, how to make your trees thrive, arborists' favorite trees, and much, much more. Tune in every Thursday to learn more because here at the Talking Trees podcast, we know trees are the answer. This week, it's part 2 of our special summer lawn care show. Zane Raudenbush, turf and herbicide specialist with the Davie Institute in Kent, Ohio, joins us again. Zane, I wanted to begin with fertilization. Is this a spring thing or something that we do in the fall?

Zane Raudenbush: Definitely want to do it in the fall. Fall fertilization is the most important time. This is when you're growing a lot of roots. Professional turf grass managers, it's all about the fall season. That is really where you begin setting yourself up for success. The next year, you'll see that we do a lot of our important practices. Aerification, maybe it's amending the soil with organic matter from top dressing, but that fall fertilization, and maybe even two fall fertilizations is really the time where the plant is putting a lot of resources into root growth versus shoot growth.

Fertilizing in the spring, you'll see the plant's putting a lot of energy into producing new shoots to develop a canopy, and not as much of those resources go towards developing roots. If you really want to prepare your plants to be able to withstand heat and drought, you want them to have a good root system, and all that happens in the fall. Yes, once you start to reach September, September's a good time to make an application. Then again, sometime in that early to mid-October is another good time to put down a second application.

You'll see if you're somebody who has traditionally done more of just a spring weeding feed and called it good, you'd be blown away by what a difference that fall fertilization will make for the following year. Fall fertilization too, Doug, really helps with the early spring green-up. You'll see that if you fertilize in the fall, that your yard will actually green up quicker than your neighbors who didn't in the spring months. Yes, fall is so, so important.

Doug: Tell me a little bit about the formulation of a fertilizer that would be applied in the fall. Is it different than what would be in the spring since you want that root growth, or it's the same fertilizer?

Zane: You often see that the nitrogen component in a fall fertilizer will be a lot higher. Often the spring fertilizers, because we're not trying to stimulate as much root growth, will contain less nitrogen. On a bag of fertilizer, you'll see those three numbers, NPK, nitrogen, phosphorus, potassium. You'll often see in a fall fertilizer that the nitrogen number will be higher, usually up there above 25%, maybe closer to 30% nitrogen.

Then you'll also see a lot of times that the potassium number is higher as well for a winterizer, somewhere in that 10% to 15% range. A good winter analysis might be like a 30-0-10, somewhere in that range. If you've done soil tests and that your soils are deficient in phosphorus, maybe you're going to apply some phosphorus as well. You'd see that maybe more like a 35-10, something like that.

Doug: All right, you bring up soil test. Tell me about that with a lawn and the importance of that for a homeowner.

Zane: Yes, the amount of information that can be garnished from a $15 soil test is just incredibly invaluable. Where you are, Penn State, I'm sure does soil testing. You'll see that you can take a sample from your lawn. You want to take a sample from that top three to four inches. I see sometimes where people take samples down eight inches. Most of the turf grass roots are going to be confined right to that upper three to four inches.

You want to sample from that region. You want to get a uniform sample. If you're interested in your front lawn, you might pull cores three to four inches deep in 10 to 15 spots from around that property, put them in the bag, and they will analyze it and tell you how much phosphorus, potassium, magnesium, calcium, all the micronutrients or many of the micronutrients are in your soil.

What you might find is that your soil might contain a plentiful amount of some of these nutrients and really you can focus on a few or you find the silver bullet that, wow, your soil is really deficient in one of these nutrients that you have not been supplying. It's pretty cool, Doug. If you have a true deficiency in your soil and you supply that nutrient, it really does make a difference. It's pretty neat to see how just a little $15, $20 tool of a soil test reveals a smoking gun sometimes, not always.

In general, soils are somewhat uniform in the undisturbed landscape, but this is where when you start dealing in the urban environment, when you think about how houses are built, this is all disturbed soil. There's no guarantee that there was topsoil put back on your yard. Yes, they're great tools. If you've never performed a soil test and you're somebody who's really into your lawn, that you really take pride in how your lawn looks, it's money well spent. Again, it might not reveal that you do anything differently, but at least you know what nutrients are there, what nutrients you should be focusing on.

Doug: Zane, here for Penn State, that soil test is only $9, believe it or not.

Zane: Okay, yes. You'll see that there's different-- often like a $9 soil test will tell you phosphorus, potassium, and it might give you a liming requirement. If you want to start to break out the micros, it might bump it up to that $20 mark. In my opinion, if you're going to go through the work to get the sample and send it in, I would fork out the extra $10, $15 and get the complete package if you're willing to do so. Yes, money, money well spent.

Doug: In that soil test, could you talk about the importance of pH? What does pH mean and is that important for growing grass?

Zane: Yes, so pH is measuring the amount of hydrogen protons in the soil. It's, looking at whether the soil is acidic or neutral or basic. In general, we would like to see the soil somewhere between that 6.8 to 7.0 pH range. Doug, when I worked on golf courses, I used to chase this pH number all the time in terms of trying to modify it. From my experiences, changing the pH isn't always that easy. The soils are an amazing buffer.

They really are pretty resilient to allowing big changes in their soil chemistry. Traditionally, if the soil is acidic, so you start seeing pHs below that 6.5 range, this is where liming can be beneficial. Applying lime will help to neutralize some of that acidity and help to bring the soil pH up. From my experiences, if the soil is more acidic, it can sometimes be easier to raise the soil pH. If you have a high soil pH, getting up there in the above 7.0, 7.4, 7.5, 7.6, the options to lower it become less.

Elemental sulfur is one of the few options, but elemental sulfur can readily burn the turf. In my opinion, knowing the soil pH is good information. It's going to tell you what nutrients might be readily available under certain pHs, but sometimes trying to chase it and modify it can be fleeting, and you're sometimes better off to just focus on the nutrients that the pH might be allowing to be unavailable.

Doug: Zane, before I let you go, I have a very selfish question about my own property, and that's one of the advantages of being a host of a podcast is you get an expert to help you. Here's the situation. I've lived in this property for 25 years. I have a big flat area out there in the shade, and it's bad soil. The water pools up on it. I don't think I can put enough compost on there. I've tilled it all before, tilled it once, put some compost down, reseeded the whole thing, but just the soil is so poor. It's what we call a quilted lawn, meaning there's not much grass in there. There's some green stuff in there, but there's not much grass. If you were faced with that, what would you tell me to do? What should I do?

Zane: You said that water is pooling in that area after heavy precipitation events?

Doug: It's definitely clay. I can get that grass to grow with a fall sowing and looks great in the spring, but as soon as things dry out, no matter how much water I put on there, I know from just my experience with soils that it's a heavy clay soil, and it's been that way forever. Even, I'll shred the leaves on there. I'll try to help that soil out. The thought of bringing in six yards of compost, and it can only be put up there by using a wheelbarrow, and brother, I'm 62 years old. I can run a wheelbarrow, but I don't know if I can move six yards again.

Zane: Yes, these are the areas where first I like to figure out what is going on with that soil and I would have it tested to really get down to what its texture is, make sure that there isn't something funky going on from a chemistry standpoint. Then, this is where I don't know what you have seeded it with in the past. Have you ever tried the straight turf type tall fescues or was it a mixture of different species?

Doug: It was probably just a shade mix that I didn't even know what was in there. That's going to be-- that'll be the first thing, the soil test. Then figuring out what I need to do there, I guess, from what you're saying, and then choosing the right type of seed for that shady area.

Zane: Definitely. You said this is a moderate shade or heavy shaded area?

Doug: As I tell everybody on the podcast, I live in an oak forest.

Zane: Okay, I must've missed that part. I don't know why I was thinking it was full sun. Doug, for the listeners here, in my opinion, moderate to heavy shade is some of the most challenging places to grow grass on the planet. Make no mistake about it, that growing grass in the shade, even for professionals, is no easy task. Those plants just simply don't get a lot of sun to make sugars from. The problem with plants grown in the shade is they pretty much have no traffic tolerance.

If this is an area that's used readily, where it gets a lot of foot traffic, mower traffic, if it's a confined area, sometimes we see where the traffic has to funnel down through gates or openings. Honestly, it can nearly be impossible to grow sustainable turf in those areas because of the shade. I don't know how you would describe this if it's like, "Hey, we don't use it." If it's really heavy shade, then I would definitely look towards more of those fine fescue species. I apologize, I must have scooted past that in your question.

Doug: Fine fescue for the shade. That's the only way to get to the pool, Zane. There's only two of us left in the house. There's one little path to the pool and back in summer.

Zane: Okay, so this is an area that's receiving some concentrated traffic, it sounds like. Yes, it's tough, make sure you're walking a different path back every time.

Doug: All right. Maybe I'll look at Pakistandra. [laughs]

Zane: Yes. Honestly, there are times where it's like, "Well, maybe there should be a path here." If there is a well-defined path and you're trying to grow grass, there are times where-- I mean this is where-- I'm not a big fan of synthetic turf, but this is why synthetic turf exists because at some point, the amount of traffic put on a turf grass surface is just-- we can't grow through that. Doug, before you go, I do have one thing I'd like to let all the listeners know as it relates to that summer stress because it's just one that I see is a epidemic of a problem and that's just people being out there mowing their lawns when they're severely drought-stressed.

If there's one thing that you can do for the benefit of your lawn, if you can clearly see that the lawn is drought-stressed, stay off of it. Do not be out there mowing it. This is where you'll start to see streaks in the lawn of dead turf where those tires crush those plants that were under drought stress. You really have to be careful how much you use the lawn when it's in the periods that we're at right now. The grass is not growing. When it's in this high heat and drought, the plants simply aren't growing. The weeds might be, unfortunately, but the grass is not. If you have the ability to stay off of it, I would encourage you to do so.

Doug: Zane, I could talk to you about this all day long. I so much appreciate your expertise and helping me with my little problem. Great stuff, and great to talk to you again. Next time I think we'll go all about weeds. There's so many other topics we could talk about when it comes to our turf. Thank you so much, Zane.

Zane: Yes, you're easy to talk to, Doug. I enjoyed it and I hope you have me back again.

Doug: Oh, I definitely will. Thanks again.

Zane: All right, we'll see you, buddy.

Doug: I think we just covered about everything we needed to know about summer and fall lawn care. That was great stuff. I'm going to start working on my little shady patch as soon as things cool off a bit. Tune in every Thursday to the Talking Trees podcast from the Davey Tree Expert Company. I'm your host, Doug Oster. Do me a favor, subscribe to the podcast so you'll never miss a show. As always, we'd like to remind you on the Talking Trees podcast, trees are the answer.

[00:15:16] [END OF AUDIO]