Irrigating Your Lawn
So Micah, I figured this episode, we would talk about irrigating my lawn, irrigating your lawn. And I have a couple of questions, specifically three questions about this. And those questions are how much water should I be putting on my lawn? And then kind of sub-question in there is, what's a good way for me to measure how much water I'm putting on my lawn? When should I water my lawn, and how often I should water my lawn? So those are the three questions we're going to be talking about today. We'll just start. Well actually, do you have a preference on which one we start with? Kind of put it in your court.
I think in general, we might be... Well with the present organization capacity of my mind right now, we'll probably bounce around a few here and there. But yeah, so this irrigation topic, that'll kind of wrap up the cultural practices of general integrated pest management strategies. So the mowing, fertilization, irrigation. So this will be the third component. And yeah, you put those questions pretty well. Those will encapsulate most of the things that you need to worry about, especially at a home lawn scenario. Yeah. I mean, first we could go with just how much water should I be putting on my lawn? And that'll dovetail into some other topics as well.
So you can break it down into, I guess, first, the goal of what you should be putting onto it, which will have a few factors. And the second part there that you mentioned, how do you figure out a good way to measure the water you're putting on? So to figure out how much you're putting onto the lawn, that's where landscape irrigation calibration comes into effect. There's knowing how much water you're actually putting out of your system or onto the lawn, as well as a uniformity.
So you can imagine if maybe you're putting the exact amount of water that goes through your irrigation system onto your lawn, but maybe it's missing some parts of the lawn. So some are still dry. So oftentimes, if you have very poor uniformity, some people will be over irrigating to make some of those dry spots look better, when in fact, maybe, potentially they are watering the correct amount.
So first you kind of want to uniformity calibrate your system, which could be as simple as making sure water's getting spread evenly across your lawn. And a simple way to do that, honestly, is put a bunch of catch cans out. And they could be as simple as a tuna can, or something with a low profile way of catching the water. So you kind of want a little wider, about tuna can width. And two, when we calibrate heads, you spread them out in a grid pattern. So you're going to put them immediately next to the heads, you're going to have them in the middle of heads. And depending on your head spacing, if it's triangular or square, it'll just set the tone for where you're putting all of those catch cans. And honestly, the easiest way is to set your irrigation, turn it on for a set amount of time, say 20 minutes or half hour or 10 minutes, depends on how long you want to be out there. Generally, I would just set it to five or ten minutes even. But obviously the longer you make it, the more accurate you can get. So basically you have these catch cans. They're catching water for a set amount of time. What you'll do is then take a note of how much water is in each of those cans. And you can literally take a ruler and just stick it in there, see how much water you've got. And the basic way of doing it is just averaging all of those catch cans. So then you would know X amount. Maybe it's a half inch of water, or a quarter inch of water, it doesn't really matter, is coming out per time. So then you'll know your irrigation rate. And that's really crucial in setting your irrigation system in general, to calibrate it, to put water down per hour, or however long. It might only be 20 minutes you need to put your irrigation on to apply a quarter inch or a 10th of an inch of water, or maybe an hour. It depends on your heads, pressure flow, all that sorts of stuff.
Okay. Okay. So just to make sure that I'm understanding this correctly, so we have three tuna can sized catch cans per sprinkler head. We put one right next to the head, one in the middle of the arc of the water, and the one at the very edge of that arc. We water for-
Yeah. And so kind of how that works is, with irrigation, you generally want the heads to have head to head coverage, is what we call it. So you want one head to essentially spray at a maximum to the next head. And in between, that is obviously all the different rates of irrigation because every head's a little different, so it's hard to explain that. But if you've got good uniformity, your heads are going head to head coverage. If you even just have a can in between the heads and at the head, then you're doing a pretty good job. Depending on how big your irrigation system is head wise and the area of coverage, you could have quite a few catch cans real quick. So once you measure all those, then yeah, you can pretty easily calculate what you're putting out. As well as if you notice one can has very little irrigation or water in there, then you'll know something's probably wrong. The area is not being hit by a head or multiple heads. So that's kind of where you can tweak your system as well as figure out your output.
"You generally want the heads to have head to head coverage, is what we call it. So you want one head to essentially spray at a maximum to the next head."
Okay. Okay. And should I expect the water output to be somewhat similar between the sprinkler head and the end arc of the sprinkler? Should that be consistent in between those two points, or does that vary a whole great deal?
It mostly depends on the head itself, I'd say. If you've got irrigation spray heads, the little popup ones, they can really be affected by wind. So when you're testing this, you're also going to want to do it on a not so windy time of the day, or time of the year. If you've got MP rotators, kind of that finger spray, those are much less affected by wind, and the distribution of that should be a bit better because the stream is a little thicker. And the other gear-driven sprays where they're kind of wider, probably an inch or so thick pop-up, those ones generally are less affected by drift. They can still obviously be affected, but those arcs, those patterns do have some variability in whether at the end of the head it's going to be more, or closer to the head it's going to be less. But with good head to head coverage, that's how they calibrate those. So if you have good head to head coverage, then it evens itself out, if that makes sense.
No, that does. Yeah. No, I appreciate it. So if you talk about the sprinklers, how do you determine this is the amount of water that my lawn needs? I mean, so we're saying, okay, we're going to measure it. We know that our lawn receives a 10th of an inch every half hour. How do we decide then, okay, my lawn needs a half hour of watering? Is it species-driven? Obviously, the climate affects it, time of year.
Yep. Actually, there's multiple factors here. So for instance, your climate, is it dry? Is it wet? And a lot of this obviously is, are you manually applying irrigation? Are you setting the controller? Is it schedule-based or is it ET-based? Maybe your controller's a smart irrigation controller where it's going off of ET, or maybe you have a rain sensor attached to where it's measuring what is occurring rain wise throughout your environment to where it's going to just automatically adjust. Where you would still want to input your irrigation rate into the controller, and then it kind of figures out what it should apply based on soil type, grass species, all that sort of stuff. So yeah, there's many things that are going to affect it. But just to kind of get an idea, we'll set some variables, I guess. We'll go with your climate, like a cool, humid. Typically would be, I don't know, the rough estimate is about an inch a week, but we don't want to just stick to that for the year. So obviously in the summer, when it's hotter, drier, it's going to increase. Maybe it's more like an inch and a half a week. So seasonally, you'll probably be about an inch to an inch and a half of precipitation. In a hotter drier climate like you go to the Southwest, it could be anywhere from two inches a week plus, depending on evapotranspiration rates, the grass species itself. Generally, warm season grasses are much more drought tolerant than cool seasons are. So if we're talking cool season specifically, there's fluctuations in there too. Tall fescues, Kentucky bluegrasses, they're pretty drought tolerant. Tall fescue is known the most. It's actually drought avoidant than it is more than drought tolerance alone. So it's roots are going super deep into the ground, sometimes as much as five, eight feet deep, so it's able to find water. So that's a, I wouldn't say misconception because they're obviously drought tolerant. Tall fescues, like our BarRobusto with the TWCA, the TWCA group, very, very drought tolerant. But they are able to source and find, or scavenge for water. Bluegrasses are a lot more variable in their drought tolerance. So those ones you have to key in on and make sure it is a drought tolerant variety, because some definitely will not be. And for instance, the TWCA group, they're able to do that work for you, and just certify them in their independently non-bias way, having a group of researchers do that selection process. I mean, generally perennial ryegrasses aren't going to be so drought tolerant. You can also get varieties that are better than others, but it's kind of more of a species selection.
That makes a lot of sense. So my lawn, we didn't cover fine fescues, but I assume they're not super drought tolerant, is that correct?
They can be in a way. They're also drought avoidant, I guess, to where they go through a summer dormancy. If it's really hot, pretty dry, they can brown out real quick. But once the irrigation or precipitation returns, then they can green up real quick as well. So some see them as drought tolerant, and there are some more drought tolerant varieties. So there's also variability there. But I mean, I kind of see it as you're still going to need to apply water. And in a home lawn situation, most of the time it's set your threshold. It's not quite the golf course scenario where it's green all the time. You're able to hold back, let it go a little brown, and watch it bounce back. But the expectation obviously with your different controller types and depending on your species and environment, there's just a lot of factors that can kind of fluctuate, I guess.
Oh, okay. Okay. Well, I mean, what you say with it, you water it, and then it greens up really nice. We've had water pretty much the whole past week. And I will say that my lawn is very green right now. It actually looks a lot better than it has.
Yep. And if you know your irrigation controller's a manual schedule where you input that information... You were mentioning, how do you know how long to put it? So if you're aiming for about an inch a week, at least when it's not super hot, maybe that's your goal. There's two methods. You can go deep and infrequent where you're applying a lot of water, maybe larger amounts, maybe a quarter of an inch of water at a time. You're doing that four times in that week to get to your one inch. Or you're doing light and frequent. So you'd be watering every day at a very small amount, a little more than a 10th of an inch to eventually get to your inch a week. I've seen a lot of studies recently where light and frequent irrigation, it's actually going to kind of improve green cover, but there's just different strategies for different soil types. So if you're doing deep and infrequent irrigation on a sand base putting green, that's not really going to work because all that water's just going to rush right through. So that's why golf courses... I mean, if you're on a green in a summer, it's getting irrigated every day. People are actually going there in the evenings. Because it's ET driving the water out of the plant. They're actually syringing to keep it cool. All sorts of stuff.
Wait. They're syringing?
Oh yeah. So golf course term here, or a sports field, turf management term. Syringing is the addition of water throughout hot, dry periods. It's less to actually water the plant than it is just to cool it down and prevent it from desiccating and withering away. So I mean, you might go onto a green. There will be hotspots where they are dry. So you'll probably hit those a little harder than others. But you're generally just putting a little bit of water across the entire surface to cool it down. Imagine when you're sweating out in the sun, that's kind of your way of cooling down, I guess, naturally rather than just going in shade. Well plants can't just get up and move over under the tree, unless if they're already there. So applying a little evening burst or mist of water cools it off a bit, and will help the plant's health.
Is there any reason why it's called syringing? I mean, the picture in my mind is a golf course super out there with a syringe.
Maybe that's kind of where it comes from. You're not heavily applying. You're precisely putting it in certain areas. I actually don't know the exact background of why that term's used. But I mean, that's the funny thing is it's such a common term when you start digging deep and researching into turf grass. But completely didn't think like, oh yeah, I should probably clarify.
Well, speaking of clarifying, you also speak of ET, evapotranspiration. For our listeners, and definitely not me, who may not know that, do you want to explain that?
Yeah. So actually I was trying to explain this to my wife the other day as well. So I'll try to remember how I put that. Because that was a good one. I probably won't though. It's basically the combination of evaporation and transpiration. So water can evaporate out of the ground. High temperatures, dry heat, literally just evaporated. That physical interaction just dissipates away. The plant interaction though is transpiration. So it's pulling water from the ground out, through the plant upwards. And then it's essentially like we do, it's breathing, it's sweating it away almost. So it's basically in the soil. What's a good way to picture this. Imagine you have a vaseful of flowers. You've got a reservoir of water in the vase, and the flowers or plants are pulling that out. Well, the water is really being transpirated away from the plant as it's taking it up, and then breathing all the gases out. So just like in rainforests and stuff, when it might be a lot more humid, foggy, cloudy above them, a lot of that coming from the plants themselves. So as that water decreases, that's the water you're losing within the soil, if you were to take it back to your lawn situation. So evaporation, transpiration, or evapotranspiration, kind of all the interactions that are involved in water loss, that's what you're wanting to replace in the system. So what that really means is, say you have a smart water controller, the factors it's going to take into account are the soil type, possibly the plant type. so if you've got difference in drought tolerance and transpiration rates, that's going to be a huge thing. And generally they're the largest ET differences, or evapotranspiration, is going to be from cool season to warm season. There's a little differences from tall fescues, say, to perennial ryegrasses. Which depending on the type of controller, it might have that option to switch. But those are the main factors as well as the added precipitation. You see this a lot in commercial settings where you've got irrigation running on a sidewalk during a rainstorm or a thunderstorm. Those don't have a shutoff or a controller to have a sensor that measures the rain is falling now. I should probably turn off the system. Which many of these controllers are now... Everything's going digital wifi. So a lot of these can now connect up to wifi, and you can actually select weather stations around you. So that's a really neat feature.
Oh, that is cool.
Kind of dummy proof in a way. And that's actually the way I'm going to go is just, I mean, I don't want to be out in my lawn all the time. I've been in that world. I actually kind of want to go away from, yeah, having to spend all that time. I want to enjoy it more and less maintenance. So you select that, it already kind of does the math. But it's calculating based on rain events in the previous few days or an average of days. So it was calculating, hey, maybe it hasn't rained at all. And here's the calculated ET loss so we're going to keep applying this amount. Or maybe it rained two days ago, it's going to take that into account. And based on the amount that it rained through that weather station data, then it's going to subtract that from what it thinks it should apply.
It takes all those kind of things into account, spits out an equation, processes it. And then says, hey, I need to run for precisely 13 minutes. If that's based on the flow rate that your system can provide, it knows in 13 minutes, it's going to put down, I don't know, a 10th of an inch, if that's what was lost through ET in the last couple of days on average.
So still, you'll probably need to know what your system can put out regardless of the system type. But it's, I'd say, obviously really important for both. But you need to know that for manual scheduling of controllers. So you can think if I need to get to an inch, for some reason you don't want to apply four times a week, I'm going to apply a quarter of an inch a time. I probably wouldn't apply that much irrigation on a lawn in one event, but I'd rather do light and frequent apps.
Light and frequent. Okay. Okay. That's good to know. Is there a better time of day to be watering your lawn? My neighbors water in the mornings. Is that a good time to water? I assume it is.
Yeah. So there's a couple things to be aware of and try and possibly avoid. I'll start at midnight and go forward in time. So in the middle of the night, maybe you irrigate. There's a cool, humid, damp environment. That's a good environment for diseases like funguses to grow. So generally that's one... I'll explain later. But it's usually done. People usually irrigate early, early morning or in the middle of night because that's actually when they can irrigate. So on a golf course or a sports field, if you've got play starting up at 7:00 AM, and if your entire system takes three hours to run, you actually got to start that at 4:00 AM, or 3:30 or 3:00, depending on when you want that system to wrap up by or stop. Ideally you want to do it kind of as the sun is breaking. So early in the morning. It's obviously not going to be as hot. So there won't be much evaporation of the water itself. There's typically less wind. So you also don't want it to be too windy. So basically this is spelling out, if you apply in the evening when it's probably hot, the wind's picking up, it could be evaporating as well as just blowing to your neighbor's yard, and you're just donating to his because. So yeah, generally that leads to the early morning irrigation. And actually what I like to do is turn it on. And I mean, if I know my system takes an hour, say, to run, I don't know yet because I'm building it right now. Say it takes an hour, and maybe I'm going to work at seven or eight. I actually want it to finish by the time I leave for work because just not wanting to waste water and that sort of thing. If there's something wrong, something broke, that thing might be still running when I'm going to work. So if you set that up to wrap up by the time you're leaving for the day, or whenever that is, if you are able to, that's a really good way to make sure, hey, nothing's wrong, it's not off, or it's not on. So if it's off, okay, you know it probably went through a cycle. If it's off and your yard is dry, it probably didn't even turn on. Then you also have a problem. So it's kind of a good way just to keep an eye on your system, always be in touch with it without having to really do too much. So that's the timing for when in the day. And I mean, you just stick with that throughout the season. But back to our talk on watering amounts, it's going to be adjusting depending on if it's ET based or a manual schedule. You're kind of going to be adjusting that through the summer, and border seasons in spring and fall.
Okay. So, if you're somebody like me, how often should I be adjusting it? I don't have a sensor on mine. Should I be looking at weather reports monthly, twice a month?
A good way is really just to know your environment first, know your environment or climate, I guess. Know your species of grass. You can look up evapotranspiration rates, and just general recommendations for different grasses. So if you have a good sense of I want to apply an inch a week of irrigation, or just precipitation total, in the spring and fall, maybe you're a one and a half inch irrigation time in the summer. So your irrigation controllers actually usually have schedules built into them. So you can have program A, B and C. So in the spring, if you're setting this thing up, you could have your spring schedule, your summer schedule, fall if they were all different. And when the time comes, you can just switch over to that different program.
That's awesome. I'll have to see if mine has that.
Yep. And if not, I mean, it could be as manual as go turn the valve by hand on and off, depending on your willingness to irrigate to that extent, which is what my system was, which is why I'm upgrading it. It'll just take more time, or your strategy will alter. For example, if that was my only method, to just go turn the valve on by hand, turn it off at another time, I'd be watering deep and infrequent. I'd probably plant a species of grass that can go longer time without water, like tall fescue. I can fill up the profile with water. It's going to be using those resources longer term. You pointed to plant a perennial ryegrass or a fine fescue, maybe you're watering a little bit every day. Not watering too much, not letting it brown out as much as you probably would a tall fescue to then recover quickly. But yeah, there's all sorts of thresholds. Are you even willing to see brown? You go to TWCA's website and there's a cool tool now where you can actually look at all this stuff, depending on your grass species, where you live, and your tolerance range for what you want the grass to look like, they have a really neat tool that tells you how much water you need to put down. So they have a cool calculator there.
Oh, that's awesome.
So definitely check that out. It should be pretty easy to find-
Do you have that URL?
Yeah. We need to get that on our website, make that easy for people to find.
Yeah. It's tgwca.org, correct?
Yup! And if you go to tgwca.org, I believe it is, there should be a calculator function there.
Cool. Cool. Well, that's awesome. Yeah. I think we covered all my questions. Is there anything you'd like to say before we wrap up, Micah?
I don't know if there's anything really specifically I'm looking at that I can think of.
I mean, it sounds from you, if you're somebody who's conscience or conscientious of the amount of water they're putting on their lawn, they really should be looking at the species they plant.
Yeah. It's part species they plant, as well as kind of their maintenance regime, or how they want to irrigate in general. Also just their threshold for turf quality. I mean, if you are okay with, for example, in the Valley of Oregon here, one of the most prevalent grasses is just colonial bentgrass. So if you go to walk down the Oregon State Corvallis area, if most of the lawns or kind of climax community species are colonial bentgrass, some clover, some yarrow, stuff like that. When summer comes, and then dry hot heat of Oregon, it's just going to brown out. Some people aren't fine with that. Some people, I grew up in that environment, where summer meant the grass goes dormant because we're not watering it. But the species that does that, it's also really good at bouncing back when rain comes. So knowing what you are, I guess, okay with in your own lawn is really first and foremost what you should figure out. Are you okay with irrigating all the time? Are you okay with a green or slightly brown, or just a completely brown lawn? That'll determine what species you might go with, or maybe you don't even care what the species already is, but then it'll affect your following maintenance practices after that.
Well, that's good to know. That's good to know. Thank you, Micah.
Yep. Yeah. And I mean, it's one of those subjects where there's so many factors it's like got to cover them all and then they all interact in some way. So often when people ask what should I be irrigating? Just a simple question. You really got to start digging deep into it. So kind of all the topics we were just mentioning today, if a homeowner asks me that, I mean, I start taking notes, looking where they live, and kind of just getting down to the personal preference of the person. And that's the ironic thing about this it's almost less turf grass maintenance than it is psychology, like social psychology. Man.
Yeah. No, that's good to know. Yeah, you covered a lot today. And it's all really helpful for me. I'm glad that it's been raining here so far. So I haven't had to yet figure out my irrigation system. But I know it's coming soon.
A little down pouring been going on over here.
Good old Oregon weather, right?
Oh yeah. Predictably unpredictable.
Well, I appreciate your time, Micah.
Awesome. Thanks, Andrew.