Garden Basics with Farmer Fred

227 Understanding Drip Irrigation

September 09, 2022 Fred Hoffman Season 3 Episode 227
Garden Basics with Farmer Fred
227 Understanding Drip Irrigation
Show Notes Transcript Chapter Markers

Some very irritated gardeners, trying to figure out drip irrigation. So, today’s entire show is on drip irrigation basics: how to install it, how to run it, how to maintain it. We revisit a chat with garden author Robert Kourik, who wrote, “Drip Irrigation for Every Landscape and All Climates.” He’ll tell us that not only will drip irrigation save you money by using less water, drip irrigation can also increase your yield. And drip irrigation isn’t just for states that have typically dry summers; it’s for any area of the country where you might get a month-long stretch of no rain. And if you tried a drip irrigation system years ago and were unhappy with the results, we’ll tell you how the equipment has improved recently to be more dependable and trouble resistant.
We’re podcasting from Barking Dog Studios here in the beautiful Abutilon Jungle in Suburban Purgatory. It’s the Garden Basics with Farmer Fred podcast, brought to you today by Smart Pots and Dave Wilson Nursery. And we will do it all in a bit over 30 minutes, because water is hard. Let’s go!

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Farmer Fred  0:00  

Garden Basics with Farmer Fred is brought to you by Smart Pots, the original lightweight, long lasting fabric plant container. It's made in the USA. Visit slash Fred for more information and a special discount, that's

Welcome to the Garden Basics with Farmer Fred podcast. If you're just a beginning gardener or you want good gardening information, you've come to the right spot.

Farmer Fred  0:31  

You know there’s an old saying: it’s a thin line between love and hate. Well, it’s a thin line between drip irrigation and drip irritation. A lot of the questions that have come in recently are from some very irritated gardeners, trying to figure out drip irrigation. So, today’s entire show is on drip irrigation basics: how to install it, how to run it, how to maintain it. We revisit a chat from a couple of years ago with garden author Robert Kourik, who wrote a great book about the subject, it’s called “Drip Irrigation for Every Landscape and All Climates.” He’ll tell us that not only will drip irrigation save you money by using less water, drip irrigation can also increase your yield. And drip irrigation isn’t just for states that have typically dry summers; it’s for any area of the country where you might get a month-long stretch of no rain. A drip irrigation system, ready to go, could save your garden in case a short drought pops up. And if you tried a drip irrigation system years ago and were unhappy with the results, we’ll tell you how the equipment has improved recently to be more dependable and trouble resistant.

We’re podcasting from Barking Dog Studios here in the beautiful Abutilon Jungle in Suburban Purgatory. It’s the Garden Basics with Farmer Fred podcast, brought to you today by Smart Pots and Dave Wilson Nursery. And we will do it all in a bit over 30 minutes, because water is hard. Let’s go!

Farmer Fred  2:06 

You have questions about drip irrigation? drip irrigation shouldn't be drip irritation. So we're gonna run through drip irrigation basics here on the garden basics podcast today with the guy who wrote the book on drip irrigation, literally wrote the book on drip irrigation. It's called "drip irrigation for every landscape in all climates" by Robert Kourik. He's written several books about gardening. And one of his bestsellers is this drip irrigation book. Robert, I guess we should just start off Who is drip irrigation right for? Which gardeners, which situations, should they consider using drip irrigation? 

Robert Kourik  2:44  

Of course, drip is really important for those people who don't get any rain at all in the summer. So that's a quite a few portions of the west and southwest. But I grew up in St. Louis, Missouri, and we got  four to six week droughts. And if you had a drip system like my dad had, you could turn it on in those droughts and just keep things moving along with a consistent water level and your plants will do a whole lot better. So that's why the book says, in all climates. 

Farmer Fred  3:17 

we should point out that your book drip irrigation for every landscape and all climates is now in its second edition. And there have been a lot of improvements in drip irrigation over the years, so if gardeners tried drip irrigation a decade ago or more, they should reconsider their aversion to it. And check out what's new because it's a lot better. there's less clogging going on now, thanks to inline drip emitter tubing.


Robert Kourik  3:43

yes, there are a number of emitters both punched in and inline emitter tubing that are more self cleaning than the old days so to speak, pressure compensating emitters now that are available both punched in and inline emitter tubing, they keep the water regular enough that you can go four or five or 600 feet of tubing off of each valve and still get the same amount of water front to end.


Farmer Fred  4:09  

And one of the beauties of pressure compensating emitters is you can then install it on a hillside without any loss of pressure.

Robert Kourik  4:18  

Exactly. technically you could go straight up and down the hillside but I always recommend just going topographically right, but but you can have lots of parallel lines going down the slope and now they have a drip line. Inline emitter tubing that has a check valve at every emitter, so that the water only drains back one slot back from the previous emitter. In other words, to drain if you have emitters every 12 inches,  the water only drains back 12 inches and stops. So you can have a tubing at the very top of the hill and tubing at the very bottom, and it won't drain everything out at the very bottom and cause a huge wet spot.

Farmer Fred  5:00 

That's a very good point you bring up. the fact that drip irrigation system is made up of many parts that people may not consider. So let's run through the parts of a modern drip irrigation system from the faucet all the way to the end cap.


Robert Kourik  5:20

well, first thing you'd put is if you don't have it built into your system. At each faucet in the garden there should be a little brass air vacuum release fitting cost about 10 bucks, and it keeps your water from siphoning back into the house water system. So the people think, well, I don't have chemicals. But if you're organic and you're using manure, it's nice to keep the manure from going back into your drinking water. So that's the first thing regardless of whether you're doing drip or hose.

Farmer Fred  5:52  

that would be called about an anti siphon valve?

Robert Kourik  5:55

It's not a Valve. An  atmospheric vacuum breaker is the technical term that I use. So that it keeps things from being the problem with slipping back into your house.

Farmer Fred  6:09  

All right, so that atmospheric vacuum breaker is what should be screwed on to the faucet itself. The first thing?

Robert Kourik  6:16  

Yes, yes. And here in California, it's code that you have to have one at every faucet on the exterior of the house.

Farmer Fred  6:25

And then you mentioned check valves at each emitter but you should probably We also have a check valve there at the faucet as well.


Robert Kourik  6:33  

Yes. So that that oftentimes is well, the, the this atmospheric vacuum breaker serves the purpose of a check valve. But you can have a check hose, a double backup, just to be on the safe side. So I've done that in the past on systems that have well water. Just make sure that things don't get clogged up in the process. But the big The next thing that you put on the system basically is a filter. And the biggest mistake that people make is they put the filter just by arbitrary thinking. After the pressure regulator, the pressure regulator reduces the pressure from sitting water of 60 to 90 psi pounds per square inch to 25 to 45 pounds per square inch so the fittings don't blow apart. But the biggest mistake I've seen is people just arbitrarily put the pressure regulator after that atmospheric vacuum breaker. But we want to put the filter there so that you have city pressure to flush the filter. Okay, so you get a filters called a y filter. And it has a little valve on the chamber that holds the screen filtering has a little ball valve and you can open that up and it strips with the pressure of the city water strips stuff off the screen to help flush it without having to take it apart. And this is very important when it comes to well water because you get big enough particles that you can flush them off three, four or five times a summer as needed. So after the filter comes a pressure regulator, what I use is a Cininger pressure regulator because under the sturdiest of all pressure regulators. In fact, in my video on pressure regulators on YouTube, I drive a truck over the pressure regulator and it doesn't break. only this one manufacturer Can  do that. So that keeps the pressure down. So now you can go to all the fittings that make up the rest of the system for watering.

Farmer Fred  8:43  

A lot of people when they hook up a drip irrigation system, they also want to be able to use a hose so they install a y-valve. And then where should that y-valve be installed?

Robert Kourik  8:56

I usually put it right after the atmospheric vacuum breaker because you get steady pressure that way, and then the water doesn't siphon back into the house through the Y Valve faucet hose bib. atmospheric vacuum breaker, then a why valves make it easy to have both drip and hose.   

Farmer Fred  9:17  

There is a great diagram in the book of a typical main drip line assembly in the book drip irrigation for every landscape and all climates. So if you're already scratching your heads, don't worry you It's in the book. 

Robert Kourik

No, no, yeah, it's all laid out. 


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Farmer Fred  11:28  

One of the big benefits of drip irrigation, you will increase your yield How is that possible?

Robert Kourik  11:36

We have a whole ebook on my website on just this topic because it's so strange to people I think oh my god, how's that possible? They go a great length explain it. But basically, if you turn on the drip on a regular basis, and keep the soil moisture consistent, the roots don't go into any shock. Now we're not talking about wet soil. Some people get carried away and turning the system on too long. We're talking about so moist as you can hardly see the color difference, but the water is there, the moisture is there for the roots, they know it's there. Whereas we may not be able to see it as much in a color difference. But the point being, if you maintain a consistent moisture level, for the whole growing season, things never dampened down or stress out from too much water or stress out from too much drought between cycles. So that's where people say, Oh, I'm going to water every Saturday or twice a month or once a month, well that puts you through these cycles where the soil gets dry enough that the roots aren't happy, then you have some run the system longer to get the soil moist again, and then oftentimes it gets too wet and the roots aren't happy because they're not able to get as much air. So the deal about getting greater yields is to turn the system on on a frequent basis. And this is really hard for people digest because they always heard Oh turn it on and off once a month or once a week or infrequently but deep well most of the roots are in the top six to 12 inches. So that's that's as deep as I worry about. I don't worry about two feet down or anything like that for trees or vegetables.

Farmer Fred  13:22  

You do advise though, before you go to this daily watering regimen that you thoroughly soak the garden, especially if it's a raised bed, make sure that the whole area is saturated. And then you can do that daily spurt, if you will.

Robert Kourik  13:37

Yes. And so that means once you know how to base the irrigation on the weather, you adjust the system to come on every day but you just for tiny amounts of water. It's like a lot of systems I'm doing one to three minutes a day to keep things happening. At the most sometimes you only need 15 minutes a day depends on the amount of water you need to apply. But the point being that this way of approaching it, you can get at least on the average 20% increase in yields. There's a woman in India that did chili peppers, and she is 38% less water but she got a 48% increase in the yields. So it can be quite dramatic.

Farmer Fred  14:27

One of the questions I get very frequently concerns people with raised beds and they have a drip irrigation system, and they complain about how they have to go back and water by hand because the plants keep wilting or the production is down. And one thing that people forget is the footprint of water and in a raised bed with all that nice loose soil in it, it's a very narrow footprint, a cylinder if you will, that has water that it descends into the soil with drip irrigation. And in sandy soil, that cylinder may only be a few inches wide If you have clay soil in the ground, that drip irrigation system profile of water might be what 12 inches, 18 inches across.


Robert Kourik  15:17  

Yeah, the heavier the clay, the wider it gets. It's more like a rutabaga. Right? 

Farmer Fred  15:22  

There you go. So I think that's the thing I see as the mistake in most drip irrigation systems in raised beds, the parallel lines in a raised bed, there aren't enough of them, they're spaced too far apart.

Robert Kourik  15:38  

Yes. Basically, I tried to get the equivalent of one emitter for every square foot. I use inline emitter tubing where these emitters are built inside the tubing but there has to be pre installed every 12, 18,24 inches depending on what you buy. So I use inline emitter tubing where the emitters are every 12 inches on a three foot wide bed I can get away with just two tubes but on a four foot wide bed I put four tubes for parallel lines the whole length of the bed

Farmer Fred  16:11  

or so we're talking 12 inch spacing between the emitters and I imagine these are one gallon an hour emitters.

Robert Kourik  16:17

I tend to try to use half gallon hour emitters because it allows you to tweak it down to less time. Whereas if you need more water, you can always leave on longer. But if you have a one gallon hour emitter, it's a little bit harder to tweak it down to less time than a half a gallon.


Farmer Fred  16:33  

Now this goes back to what I've said at the very beginning that if you haven't tinkered with drip irrigation in a while, you may be saying Oh, are you kidding? half gallon emitters are always clogging, they're always jam. That's why I go with one or two gallon emitters. Well, with the inline emitter tubing, there's usually a flushing system built into that emitter that's built into that half inch tube that greatly reduces the amount of clogging you might see in a half gallon emitter.

Robert Kourik  17:01  

Yes, they have what's called a tortuous path, and it's a zigzag pathway through the emitter. And every time the water hits a corner in that zigzag, it turns into a sideways tornado, so it keeps any silt are tiny specks  in the water. Keep that in suspension. So it goes all the way through  the torturous path or Labyrinth, and comes out through a much bigger hole than a lot of other emitters. Because  pressure compensating is done internally in the emitter, not the size of the hole going out.

Farmer Fred  17:39 

And just to be perfectly clear for everybody, the inline emitter system we're talking about is built into the half inch tubing. You can't see the emitter, it's just a tiny slot in the half inch tube. And boy, oh boy, it sure is a lot less work. There's a lot less clogging going on. You're not going to accidentally break off an emitter with your weed whacker or step on it and break it. It's worth the investment. 

Robert Kourik  18:03  

I call it the most elegant drip irrigation system. You buy the tubing, hook it up with the filter, pressure regulator, roll it out, flush it and tap it and you're done. You're not down your knees for hours trying to punch in emitters. I had a client say, Oh, we'll save some money you just put the tubing out. And this Saturday, we'll go out there and punch all the emitters in. And they spent two, three weeks going to physical therapists to deal with their wrists. After I spent one day trying to punch in all the emitters,

Farmer Fred  18:39

I've done that yes. Yeah, here's a little tip, too: is when you go to unfurl that hundred foot coil of half inch tubing. Do it on a warm day, so it will unfurl a little quicker and maybe just briefly hook it up to your water system and fill it full of water so that the tube warms up and it'll straighten out. How often do you flush these systems?


Robert Kourik  19:07 

On city water? Maybe once a year at the beginning of the season on well water, it depends on how dirty it is, but at least once a month to be on the safe side, but I had a friend with iron. Well, the water was  Full of iron. And when it gets into the air of the tubing, particularly it's out to particles, precipitates out the particles. And so we had a filter with that ball valve, so get turned on and flush it without having to take anything apart. And he forgot to do that all the time. So at the beginning of the year, when we flushed everything, we'd have to flush it for 15 20, 30 minutes before we stopped seeing particles come out. But if you do that once a month or every two weeks depending on how dirty the water is, you won't have that problem. Things won't build up. But he had a system that we put in 25 years ago, and on a well with iron water. And we didn't find out of 1000 feet of tubing on his garlic farm we didn't find a single emitter clog. Wow. Yeah. And I found that he told me near the end, he said I took away the filter four years ago. Cuz I was pissed off at cleaning it.


Farmer Fred  20:25  

There is that too.

Robert Kourik  20:26  

Yeah. And it still doesn't clog.

Farmer Fred  20:29  

All right, yeah, it's like I say, the improvements that have been made to drip irrigation systems over the years is phenomenal. So if you are reluctant to try it, because you've heard of bad experiences of yourself or others of 15, or 10-15 years ago, go back try it again. 

Robert Kourik  20:48  

Yeah, the biggest improvement is this inline emitter tubing because, like you say, when you do punched in the emitters, they break off or they get brittle in the sun or the heat. You hit them with a hoe, just a nightmare. I have friends that every spring they're out there on their knees looking for the holes and the tubing to patch up the hole and put another emitter in and takes hours.


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Farmer Fred  22:28  

Can you bury in lining better tubing under same mulch?

Robert Kourik  22:33  

You can. I always put my drip tubing on top of the soil and cover it with mulch so you don't see it. You can bury it  If you don't have gophers. we have gophers where I live in, they'll just sort of  smell the water and go straight for it. But in cities I have friends with city lots where there's no gophers, you can bury at 6 to 12 inches down and water, just the roots. And you don't even see a wet spot on the surface. But because the roots are 6 to 12 inches down, they get well watered and you can sunbathe on top of the soil while you're irrigating.

Farmer Fred  23:14  

One of the biggest tips I can offer anybody when it comes to drip irrigation is wherever you bought your system, Try to make sure they're going to be in business 5-10 years from now, and will be carrying that brand. because the fittings sometimes differ from brand to brand. Yes. And one of the best things you can do is if you're going to the hardware store, the big box store, or the irrigation supply store to look for fittings, is take a piece of the half inch tubing with you and make sure that whatever fittings you're looking at to buy, they will fit on that half inch tubing.

Robert Kourik  23:53

Yeah, if you want to get technical, there's one tubing that's 16 millimeters in diameter, another one that's 18 millimeters. But if you get the spinlock fittings, they adjust to either one. it has the post that you impale the tubing onto, and it can adjust to the difference between the two different size pipe so if you get the spinlock you dealt with that problem.

Farmer Fred  24:23  

Which is easier and which lasts the longer? the spinlock fittings or the internal fittings that you might connect the half inch tubing to?

Robert Kourik  24:33  

I like the spin lock. For two reasons. One, they are very, very sturdy. They're high quality thickwalled material. And they don't get brittle in the heat. And you can take the system apart and reconfigure things if you need to, so that you screw the little fitting over the tubing and hold it tight. But then if you want to change things, you unscrew the fitting and pull it  off the post. And you can reconfigure your system so you can use them over and over again.

Farmer Fred  25:06

Right. What are the benefits and drawbacks of using quarter inch tubing?

Robert Kourik  25:13  

Ah, I don't like quarter inch tubing anymore, but that's because it has a tendency to clog from minerals. I have a city water here. And after five years, I'm finding white particulate matter on the exterior of the quarter inch tubing and it's clogging certain randomly clogging some emitters so I've had to go in and actually add more punched-in emitters in pottery to get the kind of water I need. The quarter inch does technically have a little bit of pressure compensation, but you really shouldn't run longer than 15 feet, maybe 30 at the very most off of one attachment. So if you have a half inch supply line of black tubing, solid drip irrigation tubing, you can punch quarter in tubing in anywhere you want along that half inch but where you punch it in you shouldn't go any further than 15 feet basically.  You can't go the 2, 4, 5, 600 feet and go with inline emitter tubing.

Farmer Fred  26:20 

Yeah, that's a very good point. In fact, usually on the roll of quarter inch tubing, it will tell you right there that you're limited to a certain length as far as the run goes because of what the emitter spacing is. now the further apart the emitters are spaced The longer the run can be but in quarter inch tubing, they're usually spaced six or 12 inches apart and you're very limited in the amount of run you get on a quarter inch line.

Robert Kourik  26:45 

and they flop around. you know they move around in the garden more so than a half inch tubing full of water. But the one advantage to quarter inch in-line is that they do come in six inch intervals. Whereas you cannot buy half inch in diameter tubing, usually less than 12 inches, spacing so that if you have a very sandy soil and you've got that narrow carrot of a wet spot below ground, it works much to your advantage to have a six inch spacing.

Farmer Fred  27:18  

What about micro sprayers? I would see that as an advantage for sandy soil or for raised beds because it covers a wider area. Yes, they do put out more water , what eight to 12 gallons per hour? But you're also wasting water.

Robert Kourik  27:33  

Yeah, well they may mist. I think  to my eye it’s More of a light Mist than the Rain Bird oscillating sprinklers. so that you're actually losing more and more water proportionally. The other drawback to those is you have to keep them above the foliage. If you have a sprayer like that, and you've got in your tomato patch, it hits the foliage of the plant just drops down you got all these shadows on the other side of the plant that are not getting moisture so it's hard to do with plants like tomatoes, but it works very nicely with lettuces.

Farmer Fred  28:09  

If one is looking for an online drip irrigation company. The dripworks folks up in Willits, California have a lot of different types of equipment you can use and drip irrigation and speaking to this very problem you're talking about about micro sprayers, hitting the foliage and therefore not going as far they have an interesting one that is sort of like an upside down V pattern of water. it's on a stake and the water comes out in a fan of 360 degree fan, but it's pointed downwards at about a 45 degree angle. So you do get a wider berth of water down there.

Robert Kourik  28:47  

Yes, the way the reason I like DripWorks so much is it has national access, and then they're prejudice towards in line emitter tubing. They carry lots of other parts but they really favor in line emitter tubing. And they have a type of tubing that I only know they only they seem to have it where the interval is every nine inches. So the sandier soil The more you go for the nine inch spacing, not the 12 inch spacing.

Farmer Fred  29:15  

and they have videos online to help you get through the construction process.  Yeah, drip works. I believe is their website. And Leon. You're welcome for the free plug! 


Farmer Fred  29:34  

 Coming up in the Friday September 9, 2022 Beyond the Garden Basics newsletter, Debbie Flower and I discuss the role of cation exchange capacity, C-E-C. Why should you give a rat’s patootie about C-E-C? Only if you want to know how plants actually get their nutrition, and the role that water plays in helping plants eat. It’s in Friday’s Beyond the Garden Basics newsletter. If you were a high school chemistry class wizard, you’ll be excited to learn how the electronic charges in the soil aid and abet the feeding of plants. The rest of us, well, will need a bit more help. Maybe the charts in the newsletter will be of assistance.

Find a subscription link to the newsletter in today’s show notes, or visit our website, Garden Basics dot net, where you can sign up to have the free, Beyond the Garden Basics newsletter and podcast delivered to your inbox each Friday. Also at Garden Basics dot net, you can listen to any of our previous editions of the Garden Basics podcast, as well as read a transcript of the podcast episode you are listening to now. 

For current newsletter subscribers, look for All About CEC in the next Beyond the Garden Basics newsletter, coming out on the morning of Friday, September 9th, in your email. Take a deeper dive into gardening, with the Beyond the Garden Basics newsletter. And it’s free. Find the link in today’s show notes or at garden basics dot net.


Farmer Fred  31:06 

All right. Let's get to the meat of the matter here. how long does one runs a drip system, especially in a raised bed? And I like what you said before about thoroughly saturating the entire bed. And then just putting spurts of water on just to keep the soil hydrated of what we like to call field level moisture.


Robert Kourik  31:30  

Yes. When I have a client that starts with a new garden, we do that we monitor by hand everything down, and then we turn on the drip system that day. And sometimes it might only be on for one minute, maybe three minutes. Every day depends on the soil type and in the plant type. But basically the way you figure out all this, what seems to be complicated. Well, let me go backwards. When you read most gardening books, they say give it one inch of water, water one inch a week or whatever. So how do you convert that the drip it's almost impossible to do the calculations. So in my book, on page 83 is a chart the converts the amount of water you're going to apply to gallons, not inches, so that once you know how many gallons you need, you can control the system supply there. And the way you figure that out is a complicated sounds complicated at first, but the charts very simple to use. It's based on what's called evapo transpiration rate. evapo transpiration is the water that's lost through evaporation from the soil and transpiration from the foliage. water loss by transpiration and it's rated by one to 10 inches per month. In other words, in a really moderate climate or wet January, your Et rate might be one inch a month or less. If you live in Palm Springs, it might be 10 inches per month or more. You need to know from your local farm advisor or master gardener, what your Et rate is for the summer and they'll give you a number.  six inches is the average where I live in Santa Rosa. So I use the column that says six inches. Once you know that monthly rate, in my case six inches for the summer, you go down the chart and you can figure out how much water per square foot every 10 square feet every hundred square feet 200 300 an acre. So at a rate of the summer being warm using the six inch column 100 square foot bed vegetables is using 13 gallons a day every day. So you need to replace that with the irrigation system to keep the plants consistent cruising along on stress situation. So that once you know that you've got 13 gallons of water needed per hundred square foot. You can just do some little calculations in the back of the envelope and find out how long to leave the system on. So in my situation I did. I took a four foot wide by 10 foot long bed and I put 40 emitters in that 40 square feet. Go through all the calculations they don't want to do over the phone because it's too complicated. What it ends up being using one gallon an hour emitters to keep my vegetable bed happy. I need to run the system, seven and a half minutes every day. So with half gallon an hour emitter,  I run the system 15 minutes every day, which is a lot longer than a lot of people are used to doing. Now if they water once a week he had some do that seven times 15 minutes. You're doing it every Saturday. for an hour and three quarters to equal what the plants lost through evaporation and transpiration.

Farmer Fred  35:09  

Folks, this is why we call Robert Kourik the garden contrarian, simply because when it comes to drip irrigation especially, the old advice was to water deeply, but infrequently, which for drip irrigation might have meant running that system for hours at a time, but only doing it once or twice a week. But as anybody with sandy soil or raised beds knows there's a lot of dry periods in that week. And so you're looking at a lot of problems for plants. And the whole idea with your system, Robert, is to thoroughly saturate that soil and then go to that a few minutes a day watering regime. I mean, for years, we're trying to get people to break people of their sprinkler habit when it came to drip irrigation by saying no, no, you can't run it for minutes. You have to run it for hours. And now you come along and say oh, run, run it for minutes.

Robert Kourik  36:03

right what I call a topping off the tank so that it stays consistent, the moisture level. The other problem people have is that Oh, you're not getting the roots to grow deep. So they say, Okay, I'm going to water once a week for three hours, four hours and get that water way down there, two feet, three feet. Even if you have a tree, a majority of the root system is in the top foot, maybe 40 to 70% of the root systems and the top foot of the soil, the deeper the roots go, the longer you have to run the water to get down there. Two things happen one you over saturate the roots in the top of the soil. And to you there's not very many roots down there to absorb the moisture. But basically you focus with drip irrigation or any irrigation system on keeping the top 12 inches happy. And then the plants will be happy.

Farmer Fred  36:57  

And if you want to find out more about roots, Robert has a book as you might have thought.

Robert Kourik  37:05  

two books two books. Yes, when you got "roots demystified", that was the first one and now I have "understanding roots" that covers more and more many more roots. The roots demystified had about 20-25 roots, systems drawings, understanding roots has 141 root systems, as excavated by some person and map drawn, drawn out. These are not guesses of how roots grow. These are exactly how they grow based on excavation. And you'll see from those charts that two important things: one, the roots grow much further away from the foliage than people often assume. And they have more roots in the surface top 12 inches than they do to three feet down.

Farmer Fred  37:52  

We are getting into a totally different episode

Robert Kourik  37:56

Well, this helps with drip irrigation and raised beds because if you put an emitter on every square foot 40 emitters into the four by 10 bed, you're getting the entire root zone. And that's why sometimes in a three foot wide bed you only need two tubes because the wet spot goes out but the roots find it so that the entire root system is being irrigated. The one drawback to drip irrigation is if you're growing carrots from seed, you do need to water by hand until we get a couple true leaves one or two sets of true leaves. By the time the carrot is up as an intro to the root system is down so deep that the fruits find the moisture of the emitters but to get them very just barely started, usually need to hand water.

Farmer Fred  38:51  

But and that's one reason why at the fair oaks horticulture center the Sacramento County ,the Master Gardeners on their raised beds not only have that drip system installed to your specifications, I might add, But they also have sprinklers at each corner of the raised bed and two on the edges towards the middle. For that very purpose when they seed a new bed, they run the sprinklers to keep that seed bed evenly moist until they're up. Then they turn the sprinklers off and run the drip system.

Robert Kourik  39:22  

Right now if you are using bean seeds, you can put them kind of near the emitter and you don't really need to oftentimes use this sprayers but it won't hurt. carrot seeds is definitely a different situation. 

Farmer Fred  39:37

The name of the book is "drip irrigation for every landscape in all climates" it's by Robert Kourik. K-O-U-R-I-K.  And if you visit his website you can find out more information about all his books including the roots books and drip irrigation book, the website: 

Robert Kourik  39:57  

and cheaper than Amazon.

Farmer Fred  40:03  

There you go. Right. there. thanks, you just took money out of my pocket. okay that's fine. RobertKourik dot com for  more information and where you can buy the books as well and it's a great deal. The Garden Contrarian, we enjoy talking to him we always learn something new whenever we talk with Robert Kourik. Robert, thanks  for getting us through and turning drip irritation into drip irrigation. 

Robert Kourik

Yes, I like that. 

Farmer Fred  40:41  

Garden Basics With Farmer Fred comes out every Tuesday and Friday and is brought to you by Smart Pots and Dave Wilson Nursery. Garden Basics is available wherever podcasts are handed out. For more information about the podcast, visit our website, GardenBasics dot net. That’s where you can find out about the free, Garden Basics newsletter, Beyond the Basics. And thank you so much for listening.

Understanding Drip Irrigation Pt 1
Smart Pots!
Drip Irrigation Pt. 2
Dave Wilson Nursery
Drip Irrigation Pt. 3
(Cont.) Drip Irrigation Pt. 3
Beyond The Garden Basics Newsletter
Drip Irrigation Pt. 4