IRA FLATOW, host:
This is SCIENCE FRIDAY from NPR News. I'm Ira Flatow.
You suburbanites out there, yeah, all of you, you know what fall means? It's time to get out the lawn spreader, fill it with who knows what and seed, weed, feed your lawn. All so you can have that lush green grass next spring. But what's in that stuff that you're spreading around? And is there an alternative, a - a green alternative - a way to get green chemical-free, weed-free lawn without having to dig out every dandelion by hand? Our next guest says it is possible. Paul Tukey is the author of, "The Organic Lawn Care Manual: A Natural Low-Maintenance System for a Beautiful, Safe Lawn." He is also the founder and chairman of safelawns.org. Welcome to SCIENCE FRIDAY, Paul.
Mr. PAUL TUKEY (Author, "The Organic Lawn Care Manual: A Natural Low-Maintenance System for a Beautiful Safe Lawn."): It's my pleasure.
FLATOW: What's the first thing we should be doing to make an organic lawn?
Mr. TUKEY: Get a soil test. You - you're taking a wild guess without the test. You shouldn't be going out spending money on products, even organic products, without first digging up the soil down to the root zone - four to six inches deep - sending it to a qualified soil lab to find out things like the pH and how much nitrogen, phosphorus, potassium you have. And particularly, how much calcium and magnesium you have because all of these ratios in the soil are very, very important.
FLATOW: Mm-hmm. Okay, so, you - you've done the soil test, now what do you do?
Mr. TUKEY: Well, you obviously take a look, a test and get a recommendation and if it says put down, for example, 20 pounds of calcium, then you start to think about what kind of calcium and - and you educate yourself a little bit about the different kinds. Calcium is found in two primary products over the counter, one being gypsum and the other one being limestone. And in most of the country, it's better to put down high calcium limestone, which wasn't even available in the marketplace five years ago.
FLATOW: Hmm. Is it really possible to make, you know, a - a beautiful, green, weed-free lawn without using all those different products we see being advertised all the time?
Mr. TUKEY: Absolutely. We - you need to treat weeds as messengers sent by Mother Nature to tell us something about the soil. And we can kill the messenger in any number of ways, Ira. We can boil hot water and put it on the weeds, or we could dig out the weeds or - I hope - some people still put chemicals down. I know a lot of people still put chemicals down. And all you've done in that case is kill the messenger but you haven't changed the underlying soil conditions that make those weeds want to grow. So, the fundamental approach in my book is to take a look at the soil, fix what's wrong in the soil, so that the soil wants to grow grass.
FLATOW: Hmm. Is the idea then if you have a healthy enough lawn, you - you crowd out the weeds?
Mr. TUKEY: Absolutely. And there's a - there are a lot of cultural things you can do. You can mow your lawn higher, especially in the springtime, because a lot of people like to rake like crazy in the spring. And all you're doing then is stirring up weed seeds. And then, they keep their lawn mowed really low. The sunlight hits the soil. The weed seeds germinate and then you have a problem all season long. By keeping the grass tall in the springtime, you are crowding - you're shading the soil, that is, so that the weeds won't germinate.
FLATOW: What about all those bare spots?
Mr. TUKEY: Well, you need to get on those. If you're just kind of hoping that grass is going to fill in, well guess what, grass - we mow the lawn. So, grass never gets to go to seed. So, if you want to have a nice-looking lawn, the kind of seed that you choose is incredibly important and over-seeding on a regular basis. Any of the golfers who are listening out there, they know that if they take up a divot and you don't put the divot back, all of the golf carts have seed in them and they want you to put seed in the bare spot. You should be doing the same thing at your house.
FLATOW: 1-800-989-8255, talking with Paul Tukey, who is author of, "The Organic Lawn Care Manual." We're going to take a lot of calls because I know people - lots of people have questions. Let's - let's go to the phones. Rick(ph) in Miller Place, New York. Hi, Rick.
RICK (Caller): Hey, how are you doing today?
FLATOW: Hey there.
RICK: Great. I have two quick questions for you. The first question is, I was advised by my dad because of the harsh chemicals in those fertilizers, I was told that - that the run-off - I have also two little girls that I don't want playing on the front lawn and catching all those chemicals. He had suggested instead of bagging the grass clippings, rather than do that, just shoot it back onto the lawn and mow it back over again. And then, you know, let Mother Nature take its course. Is that dangerous to the lawn?
Mr. TUKEY: No. I mean, that's a wonderful advice from your father, you know, your father knows best. Ohio State did a study that shows that you get 50 percent of your nutrients back, 50 percent of your lawn's annual requirement in fertilizer will come from the grass itself, if you simply leave the clippings on in the lawn. The only time you want to pick up the clippings, twice a year, when those dandelions go to seed, or in the fall, right now, when the plantain and the crabgrass go to seed. Those are the two times a year to bag up your clippings and compost them. But otherwise, leave those grass clippings on the lawn because you're returning the nutrients and it's natural nutrients that are not going to leach into the water supply.
FLATOW: Are they going to disappear into the grass or are they just going to be sitting on top there?
Mr. TUKEY: They are 96 percent water, either they'll dissolve very, very quickly. They'll break down very, very quickly - especially if you're doing the natural lawn care treatment and you've got a lot of life soil organisms, earthworms in the soil. They're going to biodegrade those grass clippings very quickly.
FLATOW: So, you've got to tell - if you have somebody who mows your lawn - the kid next door or a lawn company...
Mr. TUKEY: Oh, yeah.
FLATOW: ...you've got to tell them to leave it there, because they'll take it all away.
Mr. TUKEY: Well, this whole process, Ira, in my book is - it's a - just process of thinking and education differently. It's not more work. In fact, it's less mowing, about 50 percent less mowing, about 70 percent less watering over the course of the year, but you do have to think about it differently and it begins with educating your lawn care company or the kid next door that you need to mow higher, even if you have to mow more often, you need to mow - keep that blade nice and high. And a lot of them aren't going to want to do that.
FLATOW: Yeah. What about fertilizing? How do you apply organic fertilizer and...?
Mr. TUKEY: Well, you apply organic fertilizer the same way, but don't expect it to work the same way. In the chemical fertilizers, you put down at 8 o'clock in the morning. Often times, at 8 o'clock the next morning, your lawn is greener. You say, wow, what a great product. And then you go to put down an organic product at 8 o'clock in the morning and 8 o'clock the following morning, you're out there saying, wait a minute. My lawn is not green yet. And then maybe two days later, boy and my lawn is still not green yet. Well, why is that? Organic fertilizers are not plant food.
Organic fertilizers are soil food and so you put the granular fertilizer down and the liquid fertilizer down, that product has to be consumed by the organisms in the soil. They digest the food and they excrete the food. And through that digestion and excretion process, natural fertilization occurs. So, organic products takes longer to work, but they also going to give you longer, more sustainable results. Organic fertilizers become part of the soil. They don't leach through. In fact, synthetic chemical fertilizers, according to the Rodale Institute in Pennsylvania, are - 65 percent of those fertilizers will leach away. Ground water, surface water, or they volatize into the air. If you put down organic fertilizers, more than 90 percent of that product stays in the soil.
FLATOW: Yeah. You know, I think people - you know, they may be good gardeners and have plants and they keep them in your pots and well-kept, but they don't think of the - of their grass as being a plant.
Mr. TUKEY: You know, that's true. They take it for granted. I call them the Rodney Dangerfield of the plant world…
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Mr. TUKEY: …everybody just takes it for granted. But it's a plant just like everything else.
FLATOW: And it has a little ecosystem going on…
Mr. TUKEY: Well, absolutely.
FLATOW: …in the soil.
Mr. TUKEY: Yeah, you're absolutely right, and the life in the soil. The number one takeaway point, when I speak in public all over the country, your soil needs to be every bit as alive as you and I are. It has the same needs. It needs to eat and drink and breathe. And you - and if you think about your grass plants that way or any plants in your landscape…
Mr. TUKEY: …you're going to be more successful.
FLATOW: If you're seeding now, and you know, you go into the store, you see all kinds of seed. Do you have a recommendation for which are the best seeds of the plant?
Mr. TUKEY: Well, I mean that's like asking me my favorite children. It's really difficult because there are so many different situations out there. Whether you're - if you're gardening in Florida, or California versus Maine where I live, there are so many different kinds of seeds. We have at - 17 different species of lawn grass plants detailed in my book. And I know we have a guest coming on with us at some point, he is breeding grass seeds that are going to be more drought tolerant. They're going to need less fertilizer.
That's - those are very exciting developments in the natural lawn care movement, somebody calls up and says I've fertilized my lawn like crazy, but it's not as green as your grass. How come? And it's a reason that most people don't even think of, is that the new grass breeders are breeding grass plants that are darker green.
So some grasses, no matter how much fertilizer you give them, they're never going to be the dark green that you might want as a consumer. So you've got to make sure that you understand that all - not all seeds are created equally. You need to be a good student when you're out there shopping. Don't just buy the first package you see on a shelf.
FLATOW: Why don't we bring on that specialist you were talking about. He's James Baird. He's a turf-grass specialist at the University of California Riverside. Welcome to SCIENCE FRIDAY.
Mr. JAMES BAIRD (University of California Riverside): Hi, Ira, how are you?
FLATOW: Are you familiar with the new kinds of grasses that he was talking about?
Mr. BAIRD: Yes, we're currently trying to develop a few of those that are more stress tolerant. Namely in California, what we're interested in are certainly drought tolerance, heat tolerance and salt tolerance. So yeah, that's one phase of our program in terms of trying to help ensure that turf is around for our children and our children's children to enjoy in the future.
FLATOW: Is any of this motivated by the increasing drought conditions we're having, lack of water in many places?
Mr. BAIRD: Well, certainly, you know, for us in California, I mean, water has been an issue for a long time. We've been through several droughts and I think most everyone would agree that, you know, although we're hoping that we see some relief in terms of Mother Nature helping us out in the near future, certainly this is going to be an issue to come. So we need to do all that we can to prepare for that.
FLATOW: How is that you can engineer, or you can breed grasses that need less water? What's going on in the grass that it doesn't need as much water?
Mr. BAIRD: Well, in terms of how grasses cope with less water, I mean, there's a number of different ways. There's a lot of different physiological mechanisms. It could be rooting, their depth of rooting. For example, tall fescue is one of the most common turf-grass species grown in California and a lot of the country, and we typically refer to tall fescue as a drought avoider because of its deep root system. However, having said that it's the most popular here, we're facing some pretty strict drought restrictions that is not going to keep that grass green during the summer months especially, when we don't have help from Mother Nature.
So we need to look at coming up with something better that the homeowner and general public is going to want to have around because it's I think mostly about color in terms of people's thinking about a grass in particular, is they want it green, and for us in California where we can - we have the climate, they want green grass year-round.
FLATOW: And you've got to find ones that will grow with less water. That's sort of the Holy Grail, I guess.
Mr. BAIRD: Right, right.
FLATOW: Would you agree with that?
Mr. TUKEY: Oh, absolutely, no question about it. I think that as we develop better plants, we develop better understanding, we develop better soil technologies and understanding of soil technologies, the developing grass plants that need less water, need less nutrients, we have a sustainable future in that way, and we don't have to take away lawns because a lot of people advocate getting rid of a lawn, and they think that's what I'm all about at safelawns.org, but that's not the case.
We want to have sustainable lawns. I have a 16-year-old boy. I love throwing the ball with him, and I just want to - I just don't want to waste water. I went to Phoenix, where they try to grow lawns on five inches of rainfall a year. Really, lawns require somewhere on the order of 25 to 50 inches a year.
FLATOW: All right, Paul, hang on. We're going to come back and talk more with Paul Tukey and James Baird. Stay with us. We'll be right back after this short break.
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FLATOW: You're listening to SCIENCE FRIDAY from NPR News. I'm Ira Flatow. We're talking about green lawns, and organic - growing organic grass and grass that requires less water. My guests are Paul Tukey, author of "The Organic Lawn Care Manual: A Natural Low-Maintenance System for a Beautiful, Safe Lawn"; and James Baird, he's a turf-grass specialist at the University of California.
James Baird, when you grow grass, do you genetically engineer it like we see all these fancy labs doing with other things?
Mr. BAIRD: Well, in our particular situation, with the grass that we're trying to develop right now, it's not a genetically modified organism. It's - we're looking - we're trying to develop what's referred to an inter-generic hybrid of two commonly used grass species, ryegrass and fescue, and essentially borrowing some of the genes from fescue which are typically, when you look at that species, it's more of a stress-tolerant grass, and taking those genes and putting those into ryegrass, which has a lot of good characteristics on its own, and so in this particular case we're focused again on drought and heat and we've been able to do that, but it's not genetically engineered.
These two species readily inter-cross with one another, and so it's just basically natural breeding and selection.
FLATOW: 1-800-989-8255. BJ in Sycamore, Illinois. Hi, BJ.
BJ (Caller): Hi, thank you for having me on the air. I was wondering. A year or so ago, I let my grass grow long for most of the season, to the point where it drew interesting comments, and at first it had a lot of dandelions and a lot of Queen Anne's lace growing in it. Once the grass started to get taller, the dandelions, and eventually the Queen Anne's lace, were all crowded out.
My next-door neighbor mows it about three times a week, fertilizes, does everything. His looks a little greener, but mine seems to stand up better during all kinds of weather. The only problem is I still have a little bit of Queen Anne's lace coming back this year, although no dandelions. Am I doing a better job, or how can I do a better job, and how can I get rid of the Queen Anne's lace?
FLATOW: BJ, are you saying you never mow it, you just…
BJ: No, last year I decided to see what would happen. I mowed it and said this is ridiculous. It just comes full of weeds, and I let it grow for about three months until it was almost hip-high. The dandelions disappeared. The Queen Anne's lace came back a little.
FLATOW: All right, let me get - Paul, do you have any suggestion for him?
Mr. TUKEY: Well, again, Queen Anne's lace is one of the indicator weeds. It tells you that you've got low calcium. You probably don't have enough nitrogen because you have been - you aren't fertilizing at all.
You said are you doing a better job? In my view of the world, you absolutely are doing a better job because you're just not wasting precious resources, whether they be fertilizer or gasoline to run to run the mower. So you're doing a great job, but I said low - you need to add some calcium, some nitrogen, some phosphorous, probably potassium.
Queen Anne's lace basically likes to grow in fertile soils, and what you've experienced is that by letting the grass grow, you're crowding out a lot of the other weeds. So you're doing a lot of things very well, whether you know it or not.
FLATOW: Thanks for calling, BJ. 1-800-989-8255. Jim, when you develop a grass, and I've noticed this on certain grasses, do you consider how it feels under your feet? Some of the grasses - you know, I'm thinking of some of the grasses in the South. They almost hurt your feet when you walk on them.
Mr. BAIRD: Well, they certainly are - some of the species are, I guess, softer to walk on than others, and I think about probably, like a bluegrass lawn, Kentucky bluegrass lawn, is fairly soft underfoot, but if you compare that to, let's say, St. Augustine grass down South, that's going to be a little bit courser in terms of texture.
So I guess there are some of those differences inherent within each species, and I guess a breeder tries to look at that, developing something a little bit softer, let's say, but I think a lot of it is just you're kind of stuck with what you have in terms of the species itself.
FLATOW: James, thank you for taking time to be with us.
Mr. BAIRD: Sure.
FLATOW: James Baird is a turf-grass specialist at the University of California Riverside. Still on the line with us is Paul Tukey, author of "The Organic Lawn Care Manual." Paul, do you recommend grasses, you know, because of how they feel?
Mr. TUKEY: Well, certainly. I go to visit my father. He's a snow bird. So we go see him once, and I don't like taking my two-year-old. In fact, I remember taking her for a walk outside of his house, and you're absolutely right that St. Augustine isn't comfortable to walk on, and there are now some other choices that are quite - zojure(ph) grass, for example, is a Southern grass that's very comfortable to walk on. Seashore Paspalam, which is the newest species of grass to make it into commerce zones seven through 10. So we're talking the Carolinas, down into Florida and over into Texas, and that's a grass that's very soft underfoot.
So all grass plants are not created equally, and a lot of people don't understand that.
FLATOW: If you want to fertilize organically, is it better to go to, you know, the lawn store and buy a bag of organic fertilizer, or should you just mow in the clippings?
Mr. TUKEY: Well, mowing in the clippings again will give you 50 percent, but you know, if you're going to make a transition from a chemically treated lawn, and you have a certain expectation of your appearance, you're going to have to get involved with some organic fertilizers.
We have a few on our Web site that we recommend, but there are many, many good ones, and in the first couple of years of transition, you're probably going to need some help.
Again, don't expect the same results. Don't expect it to work the same way, and again, a granular fertilizer works very slowly. You're going to want to get involved in some liquid fertilizers and maybe a new thing, which a lot of people don't know about, which is compost tea or compost extract.
FLATOW: Oh yeah, we've talked about them, and you can make your own.
Mr. TUKEY: Yes.
FLATOW: If you're planting sod, for example, and you wanted - you've got new sod down, and you want to - of course it hasn't been grown organically. You want to switch it to organic stuff. What's the first thing you should do?
Mr. TUKEY: Well, again, that's - it goes right back to that soil test and making sure that your soil is as healthy as possible before you put that sod down because I've seen people lose a good stand of sod in just two or three months because they didn't prepare the soil.
It looks great that first six weeks because there's still plenty of residual chemical fertilizer, but those roots are going to go down. They're not going to find what they're looking for. Make sure there's plenty of fertility, plenty of compost. Work plenty of compost into that upper layer, and you're going to water it regularly as you put it down during that first six weeks until the roots take hold, and then stay on it. Stay on it, and by that I mean you're going to want it that first year, keep some liquid organic fertilizer and some liquid compost teas going down.
FLATOW: 1-800-989-8255 is our number. What's the biggest mistake that people make with their lawns?
Mr. TUKEY: They mow too low. That's probably number one. They scald it, and so then the sun comes down, like I said, and all kinds of weeds sprout. People tend to over-water. People who have sprinkler systems will water every single day. Your goal should be to water once a week, if at all, and always water in the morning, if possible. Avoid evening watering, especially in the summertime when there's high humidity.
FLATOW: Let's see if we can go to Don(ph) in Sun Valley, Idaho. Hi, Don.
DON (Caller): Hi. Thanks for the program. I'd like your guest to address the importance of adding trace elements to a lawn enough so the importance of the microscopic lights in the soil and how chemical applications will pretty much kill it and the important of aeration.
Mr. TUKEY: Well, I agree with everything that you just said. And as I said earlier, if you were listening, that the soil needs to be every bit as alive as you and I are, and that's with microscopic organisms and organisms like earthworms that we can see, and chemical pesticides and fertilizers that you put down, they disrupt that natural soil cycle, and so you - that's another reason to avoid those products.
Mother Nature knows how to grow things. Otherwise we wouldn't have tall forests. When the bark falls off the trees, the pine needles, the leaves, all that stuff falls down into the forest floor. The microorganisms in the forest soil biodegrade those things, and the trees grow incrementally taller.
Your lawn and your garden can function essentially the same way, and as an organic lawn-care approach, all we're trying to do is enhance that natural system. And by the way, I'm going to be in Sun Valley speaking on October the 16th. Stop by.
FLATOW: Stop by. People will say, you know, if you leave the grass clippings, if you mow them back into the lawn, they're afraid of having all this thatch.
Mr. TUKEY: It's not the same thing. Thatch and clippings are not even remotely the same. Thatch is a buildup that you get after too much fertilizer application. It's actually dead stems of lawn that's still connected.
Grass clippings, it's - you're clipping off the top of the grass plant, but they don't contain any lignin, and it's dying roots and stems of grass is thatch, and that's what - again, that's what you get from over-fertilization. You're going to see that a lot in a St. Augustine lawn, for example, and when you get too much thatch, then the fertilizer, the water, the air can't get to the soil, and then you have to rent a mechanical de-thatching machine or get a bamboo rake and work like crazy.
When you have an organic lawn, Ira, the organisms in the soil are going to naturally decompose that thatch, just like they naturally decompose the clippings.
FLATOW: And this is a good time to do all this, the fall.
Mr. TUKEY: This is the best time to do all this - September, October and into November, depending on where you live. It's a great time to over-seed because you want to get the roots established heading into winter. It's a way better time than spring. You don't have the competition from weed seeds.
Unfortunately, it can be some work, but you do need to get out there and rake away those leaves. You don't want to leave heavy layers of leaves on your grass, or you will get some winter-kill and some dead spots.
FLATOW: And so, you know, people talk about mowing the leaves into the grass. You don't suggest that.
Mr. TUKEY: Well, if it's just a few leaves, I do. I think it's fine to mulch the leaves right in. But if you have thick layers…
Mr. TUKEY: …that's not a good idea.
FLATOW: Okay. Well, I want to thank you for taking time to be with us. Those are some great hints.
Mr. TUKEY: Well, thank you very much. I appreciate it.
FLATOW: And there…
Mr. TUKEY: Safelawns.org. Just email us any questions.
FLATOW: There you go. And there are a lot more hints in Paul Tukey's book, "The Organic Lawn Care Manual: A Natural, Low-Maintenance System for a Beautiful, Safe Lawn."
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