Help Your Lawn Thrive this Spring PART ONE

In part one of this two-part episode, Zane Raudenbush, turf and herbicide specialist within the Davey Institute, shares his tips to set your lawn up for success this spring.

In this episode we cover:  

• Cool weather impacting spring lawn care (1:02)
• First thing to do in your lawn this spring (2:44)
• Garden weasels and biochar (4:08) (5:06)
• Soil temperatures (6:55)
• Dry, clay soil invigoration (8:24)
• Lawn fertilizers (11:37) (16:17)
• Bio stimulates fertilizers (14:21) (15:29)
• Soil testing (18:16)

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

Listen to our Talking Trees with Davey Tree podcast episode about biochar and how it benefits landscapes, Why Biochar is Important & How it Can Be Used in the Landscape.

To learn helpful fertilizing tips, read our blog, Grass Yellow After Fertilizing? Here’s How to Repair. 

Connect with Davey Tree on social media:
Twitter: @DaveyTree
Facebook: @DaveyTree
Instagram: @daveytree
YouTube: The Davey Tree Expert Company
LinkedIn: The Davey Tree Expert Company 

Connect with Doug Oster at www.dougoster.com. 

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

Transcript

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Doug Oster: Welcome to the Davey 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. I'm joined this week again by Zane Raudenbush. He is turfgrass and herbicide specialist for the Davey Tree Expert Company. Even though he has a PhD, it took him three minutes to figure out how to get his headset to work for this podcast. How are you doing, Zane?

Zane Raudenbush: I'm good. I'm good. I'll definitely stick to the agronomics and away from any IT-related issues.

Doug: I'm telling you, [chuckles] it doesn't matter if you're a PhD or what. Almost every time I get on the podcast, there's always some kind of issue in getting the audio working. Today with Zane, as always, we're going to talk all about lawns. In the past, when we've talked, I've discovered that fall is a fantastic time to deal with lawn issues, but everybody's mind turns to their lawn in the spring, Zane. We've had here in the east a cool start to the season. I'm thinking from what I've learned from you, and you tell me if I'm right or wrong, but to me, it's too early to put any seed down. I think the soil would still be too cool?

Zane: Yes, you are correct in that if you put seed down right now, you could expect that it will take probably 10 to 14 days to germinate. Your timing is good, Doug, because this is the time to take stock of where is my lawn right now. If you're out there on your property now, at least where I live in Ohio, the grass has just now started to green up. People have put their first cut on their lawns in terms of, you're maybe only mowing 40% of the lawn, you're cleaning up the tall stuff, and other parts of the lawn really aren't growing yet.

This is an important time to take note. Are there areas where there's bare soil where the lawn has really thin due to traffic or shade, and to be prepared to get your supplies that over the next week or two to start getting that soil scratched up, get some seed in the ground. Then too, if you're someone that is taking stock of your lawn and you have a lawn care service that applies treatments to your lawn, try to make sure if you need to do any seeding work that they do not apply any crabgrass pre-emergent to your lawn. Otherwise, you're not going to be able to overseed, or you're going to have much lower success.

Doug: Let's talk about timing here. It sounds very important. We're going to set it to your lawn, Zane. I want to follow this through. What's the first thing to do? Am I dealing with crabgrass first, or am I seeding? You take me through how you would do it.

Zane: I can take you how I would do it because I just did it at my house. I have a few areas right off of our deck that we use heavily. They've been trafficked all winter. People walk on them, so they've thinned out a little bit, and I do have some bare soil. What I did was I went through and took my garden weasel and just lightly scarified the soil. I put my seed in, and then I took a mixture of soil and biochar. I've been playing around with biochar quite a bit lately, Doug. I top dressed that area after I seeded it and watered it and trying to keep people off.

My goal is to get these plants to germinate in the next two weeks, begin to establish, and then I'll come back and apply my crabgrass preventer in more like mid-May, so a little bit later than I would like. Typically, in my area, I actually don't see crabgrass germinating in the lawn until that first or second week in May. You might find it germinating along a curb edging or a driveway a little bit sooner, but in a full turfgrass lawn area, typically, it's going to be first, second week in May.

Doug: Let's talk about that amazing garden weasel. Not everybody knows what a garden weasel is, but anybody I've ever known that bought one, it's indispensable in so many jobs in the garden. That seems perfect to set up a spot to seed. Then we've got to get into biochar. Tell people what a garden weasel is. I think most people know, but some might not.

Zane: A garden weasel, it's got a long handle, and at the end, there's usually three sets of tines. Maybe, Doug, you could help me with the description. There are a set of tines, and they roll across the surface, and it's all about pressure. The more pressure you apply, the more it's going to disturb the soil. If you're light with the pressure, it just dimples holes in the surface, and if you're really hard with the pressure, you'll actually begin to break the crust up and create a little bit of tillage there.

Doug: They cross each other. There's three things in there, and it's a really amazing little thing. Now, let's get into the biochar. We've talked extensively before on the podcast about biochar, but let's go into it a little bit and how you're using it in the lawn.

Zane: Biochar has a bunch of great properties for the soil in terms of nutrient retention, reducing bulk density. My purposes of using it in this instance, where I'm mixing it with the soil, are twofold. One, it's going to hold moisture. Anybody that's listening to the podcast, when you plant seed, when you're putting turfgrass seed in the ground, the most important thing to do is keep the seedbed moist. You don't want it to be soaked. You just want that surface to be moist. This time of year, watering it twice a day is sufficient.

In the summer months, it's probably going to be four times a day. What biochar does is it's going to help to hold some of that moisture. It's going to keep the seedbed a little bit more moist. The other part, Doug, is it's black. That dark color is going to help to warm the soil, bring the soil temperatures up. Then obviously, I'm looking for the long-term benefits too of increased nutrient retention, increased microbial activity. My purposes of adding it to my soil that I'm sprinkling over the seed is to hold moisture and actually add heat, absorb more heat from the sun when it's out.

Doug: Let's clarify on the watering. That amount of watering is to get the seed to germinate. That's not after it's up and growing. I just want to make sure people understood that.

Zane: Yes. Don't be watering your established lawn four times a day, or you'll be real upset with me. The whole goal of when you plant seed, light and frequent. Literally, all you're trying to do is just enough water to wet the surface. If you have a sprinkler out there or you're doing it by hand, it's just a quick pass over, wet the soil, and you're on to the next spot.

Doug: You think where you're at, it's okay, warm enough. Soil temperatures are, where would you guess? 50s?

Zane: Yes. In the day when the sun is out, we're getting up into the lower 50s. Then because we've had these cool nights at times, it'll drop right back down to the mid-40s. For turfgrass, 45-degree soil temperature is a key number there. That's really where you get below 45 degrees, the seed is just going to sit there on the soil and really not germinate. We are just entering the window, and that's why you'll see it might be more like 10 to 14 days for some of those plants to actually start to germinate.

Doug: Even if you're planting early, the seed will sit there, right? It'll be okay as long as we keep it wet. As long as it doesn't dry out, we're okay, right?

Zane: That's correct. There's two scenarios, Doug. There's the scenario like I described where I've got some thin areas, I have existing turf around it, and we're just trying to thicken it up. That's one scenario, and that can be done very early. Then there's the scenario where somebody's trying to totally establish a yard from scratch. Maybe they just had a home built, it's all bare soil. That's where, if you put the seed down early, the negative there is it could wash away, you could get a lot of soil erosion. That's where you try to do that at more of the ideal time versus saying, "I'll do it in January," knowing that seed will sit there and come up. That's a bit of a different animal.

Doug: Zane, I've been waiting to spring this on you. I guess I should have waited longer, but I've got an area, doesn't have any grass on it. It's not where my grandkids play. There's a lot of clay in there. It's in the shade of oak, and then one side, hemlocks. I don't think there's any way I'm going to grow grass under those hemlocks, but I've got to do something. I've been cutting up the leaves for the past three years and just leaving them on there, and they're just decomposing.

That area just dries out so much because it's so clay, but it's too big, I think, for me to bring up enough compost. Normally, if I was doing a vegetable garden, I'd get the compost, I'd put it under the bed, I'd plant it in, everything would be hunky-dory. I'd be like, "Oh, look at it, everything's going great." This area is so big, I just don't know what to do. I've got a little tiller. Looking at it, I've got some bare spots that are like little hills that I can just see as pure clay. Help.

[laughter]

Zane: If you were one of our clients and you poised that to me, "Help," I'd say, "What's your address?" I'm going to look at your site using aerial imagery. We have really high-quality aerial imagery that I'll look at the site. A very important question for this is how many hours of direct sunlight is this area getting, Doug?

Doug: Barely any.

Zane: This is where we've got to manage the expectations. The two things that really cannot collide in the same sentence are traffic, so in this case, your grandkids and heavy shade. That's a recipe to have bare soil. Turfgrass just cannot sustain growth in the shade when it's going to receive a lot of traffic. Shade, in my opinion, is anything that's getting less than three hours of direct sunlight.

If you would go out to that site and say, "When there's leaves on these trees, it really doesn't get any direct sunlight," that's going to be a continuous challenge. Probably wouldn't matter if you'd amend the soil, plant a different species. It probably would require you to change the traffic pattern. Is there a different place where your grandkids could really set up shop and do their thing?

Doug: Maybe I'll just lock them in the she shed and leave them there.

Zane: [laughs] I will say offline, though, we could definitely take a closer look. That's typically what I do is I ask for the address. I will look at the aerial imagery, try to get a sense for how much use, how much sunlight. I'll look at the soil data for the area. Part of my job is to help people manage their expectations. When I start hearing heavy shade and traffic, if you would say we can take the traffic off of that site, then we might look to amend the soil, plant a species like fine fescue or tall fescue, something that's got a little bit more shade tolerance. I would probably push you to do that more in the late summer, fall. If we had to do it now, we could, but I would push.

Doug: I get enough just weedy things growing in there where it does become greenish, and it's not a muddy mess. Years ago, I had tilled the whole thing, seeded it. Of course, right off the bat, I had this great lawn. I don't even know what species I was using. I'm sure I went for some kind of mix that was shade-related. Again, the quality of the soil, the lack of sun, and you and I have talked about this before, I know that it's a losing battle. I'm going to have to figure out something for that space. On your list of things to do after you've done your seeding, what's next for your lawn?

Zane: My lawn, I'll put down some type of complete fertilizer here just to try to stimulate some growth and get the area to fill in.

Doug: Give me the breakdown on the fertilizer. Is it high nitrogen, or is it balanced? What are you picking there?

Zane: I'm actually using a new product that we've developed at Davey, not to promote anything specific to us, but I've been really interested, Doug, in exploring more of these compost organic-based fertilizers. For a lot of the listeners out there, a lot of the traditional lawn fertilizers are using synthetic nitrogen sources like urea and ammonium sulfate, which are great, very efficient for the plant, but actually, part of those bags of fertilizer are filled with crushed limestone or bentonite. We call those filler materials, and that's what helps create the analysis of the bag.

When you want a 20-0-4, half of that bag might actually be limestone. These organic-based fertilizers are still using a little bit of those synthetic sources, but instead of having limestone filler, we're using things like poultry litter and compost and biochar to be the fill material. This fertilizer I'm going to apply is a 12-0-4 organic-based fertilizer, Doug, and it contains poultry litter and seaweed extract and biochar. It also contains some urea and ammonium sulfate.

It's interesting. It has a little bit of the traditional sources to give you the quick promotion of green up and growth, but then it has these organic sources of nitrogen that will break down with time. Again, in the spring, you've all experienced that the grass has no problem growing. We're just trying to make sure that it has a little bit of improved color and that these areas that I seeded have a little bit of nutrition there, too, to help get them to establish.

Doug: Is this product something that Davey's making, or is this something that you're bringing in? What is this stuff?

Zane: That's a good question. We're working with a partner. It's called Ocean Organics, and it's a fertilizer manufacturer. They're in Waldoboro, Maine. They predominantly make seaweed extract. If any of your listeners have ever used any seaweed extract material or what we might call biostimulants, this company, actually, Doug, sustainably harvests seaweed from the shores of Maine. They bring it back, process it, and the leftover seaweed is what they're making part of our fertilizer with.

They make the fertilizer exclusively for Davey, we purchase it, and can apply it to our customers' property. It's something just unique to us. This is a new initiative. This is something brand new for 2025. We've been testing it last year, rolling it out on a smaller pilot. That's what I'm applying to my yard, just to, again, get some feedback from the material, and it's a really, really nice material.

Doug: On a side note, I took a trip to Maine in the '90s and brought back a big, giant trash bag of seaweed to put in my compost pile, [chuckles] it made all the difference in the world.

Zane: It's incredible. The biostimulant world is quickly evolving, and the proof is now in the pudding. The thing about biostimulants is, at least in turfgrass, they don't always provide a response, but it's pretty well documented. When plants get into stressful conditions, that's when you start to see the effects of biostimulants showing through. When the plants get stressed from heat, drought, pests, those products help promote better quality. We also just see better rooting, better fine root hairs.

Doug: Could you explain to us the three numbers that you talked about there? Because not everybody knows what those are. What you're using is 12-0-4. 12 is the nitrogen. What's the 0 and the 4?

Zane: On a bag of fertilizer, by law, we'll be required to show you the percent of NPK. Nitrogen is the first number, the second number is phosphorus and the third number is potassium. In this fertilizer, it's 12% nitrogen, 0% phosphorus, and 4% potassium. For turfgrass, one of the beautiful things about the graminoids or the grasses is they're unique compared to other crop species, Doug, because they can, at the rhizosphere-- For your listeners, the rhizosphere is the direct area around a root.

When you think about a root growing in the soil, when you hear the term rhizosphere, we're talking about the area where the soil is contacting the root. Grass plants have the ability to change the rhizosphere to help them extract nutrients from the soil. In some soils, there would be plants that simply would not be able to pull the nutrients out of the soil. The nutrients would be so tightly attracted to the soil colloids that they just wouldn't be available to the plants.

Grasses can produce root exudates that allow them to extract these nutrients. That's why we see that you'll hear a lot of people in the turfgrass business, they focus a lot on nitrogen and less on the phosphorus and potassium, simply because grasses are really good at getting those nutrients out of the soil, and often, most soils contain appreciable quantities. Every once in a while, they don't. If you've listened to Doug and I riff before, you know that that's why we want a soil test to make sure that we're just not making assumptions that aren't true. Most soils do contain enough phosphorus and potassium to sustain turfgrass growth, but every once in a while, there are some that don't, and we want to know about that.

Doug: Let's go right there, then. Let's talk about the importance of a soil test when you want your lawn to look good.

Zane: It's so simple to do, and it costs very little money. Most of these soil tests can be $15 to $30. If you're someone who's really into your yard and takes the time to either pay a company to fertilize it or you're doing it yourself, you certainly want to make sure what you're putting down is addressing any potential deficiencies or is actually what your lawn needs. More often than not, what I see, Doug, is that you're putting down nutrients that you don't actually need. You could potentially be buying a fertilizer that's less expensive or free up those dollars to do something else.

Liming is another one. Lime is another thing that I see that people sometimes just do to do, and a soil test might reveal that your pH is just fine. In fact, for grasses, we want it usually a little bit more on the acidic side. That's oftentimes where I find that people have been liming for a long, long time, and I'm like, "Let's take a soil test. Let's look and pull a soil test, and we'll see. Your pH is 7.1. In fact, you've probably limed too much now."

Yes, a soil test for what they cost really allow you to, one, understand if you do have any efficiencies. If you do, you can select a fertilizer that might address some type of phosphorus, potassium, magnesium deficiency. More often, what I find is that the soil contains plentiful amounts of those, and you actually could just end up buying a less expensive fertilizer.

Doug: All right, Zane. As usual, this is going to be a two-parter because I've just scratched the surface. When we come back next week, I want to talk about diseases, I want to talk about pests, and I want to talk about having a great lawn. You've got to start it off on the right foot. As always, great to talk to you. We get to see each other, so I always like seeing in the background. I see Zane has his microscope, but then he's got all the artwork from the kids behind him, which is cool, but there's a houseplant there with a yellow leaf on it. I don't know what that's all about.

Zane: [laughs]

Doug: You better take that PhD and start working on that houseplant.

Zane: You know it.

Doug: All right, Zane. We'll talk to you next week. Thanks so much.

Zane: Good to see you, Doug.

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Doug: I've got loads of questions to ask Zane next week. I learn so much from him every time we talk. All right, fellow tree lovers. I want you to tune in every Thursday to this Talking Trees podcast from the Davey Tree Expert Company. I'm your host, Doug Oster, and I want you to do me a big favor. Come on, subscribe to the podcast so you won't miss a show.

If you've got an idea for an episode, maybe a comment, there's two ways to reach us. You can send us an email to podcasts@davey.com, that's P-O-D-C-A-S-T-S@D-A-V-E-Y.com. You can also click the link at the end of our show notes to text us a fan mail message. Your ideas might be on a future show. We'd love to hear from you. As always, we'd like to remind you, on the Talking Trees podcast, trees are the answer.

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