Xtremehorticulture

Xtremehorticulture of the Desert

Parts of Drip Irrigation System

Leave a Comment / arrows, closed loop, drip irrigation, flush, irrigation design, water pressure /

Q. When installing drip irrigation, what irrigation parts do I need? Drip irrigation must have a filter and a means to regulate the pressure, a pressure regulator. https://www.digcorp.com/wp-content/uploads/digcorp/DripZone-1.pdf accessed on August 1, 2023. A. Make sure there is some sort of filtration, a pressure regulator to lower water pressure, and a way to “flush” the irrigation lines of debris, algae, and bacteria. Many people forget the flush part because they are used to using city water which is very clean. Every drip irrigation system needs these parts. It makes no difference if the filter or pressure regulator is first but drip systems need lower pressure. It works either way (pressure regulator first then filter or vice versa) but the arrows of water flow are important. A flush valve can be as simple as a ball valve connected to the irrigation circuit but it must be buried so it can be found and used. https://www.landfx.com/docs/item/202-land-f-x-drip-irrigation-design-and-graphic-conventions.html accessed on August 1, 2023.             The flush valve (oftentimes just a ball valve or on and off valve) is placed farthest away from where water first enters the “system” and hidden from site but easily found and used. The “flushing operation” involves cleaning the filters as well as cleaning the lines of algae and bacteria with the flush valve.             Cant say how often to flush the lines but drip irrigation MUST have clean water to operate. Well water is a “dirtier” water than city water. Wells pick up sand and other sediment that needs regular and periodic flushing. Once you get into a “rhythm” for how often to flush (every other time you water or every fifth time you water??) it doesn’t change much. Just plan on it when you use well water. Hunter screen filter and pressure regulator in a bag.             Lower the water pressure with a pressure regulator. Water pressure from a municipality fluctuates depending on how close you are to the municipalities water pump or reservoir. A plastic pressure regulator helps lower the water pressure into the “normal range” to operate drip irrigation. The pressure of water from wells may vary. For most homeowners, the water pressure range for smaller drip systems is approximately 25 to 30 psi. For larger drip irrigation operations (half acre and above), water pressure of drip systems may need to be more than this. All PE tubing specifies its operating pressure and other important information such as emitter distance, size of the emitters, etc.             Water used in drip irrigation needs to be particle free. Clean it before it comes in the drip lines. Drip irrigation relies on small holes that can plug, to deliver water. Clean water requires filtration. Even though water from municipalities has been filtered, filtration is still needed for drip irrigation. Most commonly and inexpensively, screen filters (screens are 120 -130 “mesh”, which means 120 to 130 holes per each square inch) are used. The filter is added, usually after an irrigation valve. Pressure regulators must be used to protect the drip tubing from operating at too high of a pressure. If incoming pressure is to great or fluctuates, a more substantial pressure regulator (such as brass or more permanent type) should be used. Incoming water pressure should not exceed the PE or fitting operating pressure. Rainbird pressure regulators https://www.evergreen-irrigation.co.uk/product/rain-bird-water-pressure-regulator/             Regular flushing cleans the lines of debris, algae and bacteria. It is important to flush the lines every time repairs are made as well as regularly. Part of the “flushing operation” requires a separate “flush valve”. This is particularly true if using a fertilizer injector.             When designing drip irrigation, I prefer the “closed loop” type of irrigation system design. That’s where there is a header and footer that “close the loop”. Closed loops minimize the number of places where you have to flush and “evens-out” the water pressure of the system. It costs a bit more to install but the benefits are worth it in my opinion.

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Plant Roots Prefer Water and Nutrients Applied to the Same Place

Leave a Comment / drip irrigation, plants, roots, vegetables /

Q. I have read that plants grow better with water delivered to their roots, at the same spot, over and over again. Is this true? Eggplant growing with drip irrigation in a raised bed without sidewalls. A. Yes, it’s true but you probably won’t notice the difference. Why? Unless you compare plants growing with water applied to the same spot, over and over, with plants watered at different places you wont see much difference.              Plant roots get used to the amount of water and air when water is delivered to the same spots and depth, over and over. That is one reason why drip irrigation, along with the proper spacing of emitters, is so successful as long as the plant “wets its roots” to the appropriate depth each time. Watering with a hose will not as consistent.             Water should wet the roots to the same depth every time. Small shrubs need to wet their roots to a depth of 12 to 18 inches, medium sized trees and shrubs 18 to 24 inches deep, and tall trees or shrubs should have wetted roots to a depth of 36 inches deep. This water should be applied to at least half the area under the plant’s canopy. Obviously then large plants need more water applied to them, and this water applied to a larger area, than the smaller plants.

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Variable Output Drip Emitters

Leave a Comment / accuracy, drip irrigation, emitters, problems /

Q. I read somewhere not to use the type of drip emitters that you have to open to get water. What say you? Two emitters are not enough to accurately provide water to a tree as it gets larger. If these emitters flood the area under a tree the water should be captured by a moat or ring of soil surrounding the tree about six feet in diameter.  A. They are called variable output drip emitters. I don’t like what are called “variable output drip emitters” (the kind that releases a different amount of water depending on how much you “open” it using a dial). You don’t know how much these drip emitters are releasing because there is a loss of precision. Opening it varies the output of water from 0 gph (no water) to 10 gph (wide open). It depends on how much it’s opened, and it doesn’t tell you the amount of water it delivers. “Wide open” might be more than 10 gph for some manufacturers. For me it’s like playing “whack-a-mole” when variable output drip emitters are used. Using variable type drip emitters makes it difficult to tally how much water is used. Variable flow or variable output drip emitters don’t have much precision. You can open it or close it but how much you give a plant is anybody’s guess. The irrigation industry has started to color code drip emitters. If single drip emitter has a specific color, such as red, all of the emitters from that manufacturer are the same. If all the emitters are the color red (2 gph) for example than any drip emitter with a red color will release the water at the rate of 2 gallons per hour. Netafim.

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Run Drip Irrigation Any Time

Leave a Comment / drip irrigation, night or day /

Q. Should drip irrigation run during daylight hours or at night? I’m assuming there would be less water loss from evaporation if they run at night but that makes finding bad emitters more difficult. You can turn on drip irrigation just about any time but running it at night is best. Running drip irrigation at night doesn’t wet the leaves so disease is not a problem. There is less surface evaporation from the soil. A. Time of day doesn’t matter if you’re using real drip emitters and not adjustable emitters that flood water on the soil surface. If there is standing water after using your drip emitters, then evaporation is a problem and it’s best if it’s done at night. Drip irrigation like from this drip tubing releases water slowly over periods of hours so that it is less likely to puddle and run to low spots.             Drip irrigation is designed to slowly release water in one small area so this water enters the soil and doesn’t puddle on top.  When adjustable emitters are used, the kind that can be adjusted to release more or less water, then this water may form water puddles on top of the soil.             The key to evaporation is whether there is standing water. If it is truly drip and not adjustable drip emitters which flood the area, then evaporation is minimal.             Always check first with local laws, regulations or policies regarding when it is lawful or advisable to irrigate. Basin and bubbler irrigation is very efficient but, unlike the irrigation around this very large pine tree, the basin should be enlarged each year to hold more water. The basin under the tree should occupy at least about half of the area under the canopy.             Consider applying wood chips to the soil surface instead of rock to conserve water. Wood chips on the surface of the soil where water is released will slowly “rot” wood chips and improve the soil in only a few months. This soil improvement helps water released from drip emitters to enter the soil more quickly and reduce puddling and evaporation. Woodchips on top of desert soils and in contact with water improve these soils and help water to penetrate more deeply to the roots of plants. This improvement can happen in the first year after the surface mulch of woodchips is applied in the irrigated area.             Free woodchips are available from the University Orchard in North Las Vegas or the Cooperative Extension office south of the airport. Call the Master Gardener helpline at 702-257-5555 to get directions where to get it.

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Use Five Gallon Buckets in Place of Drip Irrigation

3 Comments / can i water my trees with buckets, drip irrigation, five gallon buckets, how to water trees with buckets, water conservation /

Q. My pine trees are over 20 years old and very tall.  I looked on the net and found a YouTube video out of Kansas showing a man using a 5 gallon bucket with a pin hole in the bottom for the purpose of watering them. I called my landscaping guy and he said that I am wasting water by watering that way.  Am I doing right by watering with buckets or is he correct about this method? A. Using a bucket with a small hole in it works just like drip irrigation as long as the holes is small enough that it lets the water out very slowly. Using buckets is similar to the very first form of drip irrigation which was sinking unglazed ceramic pots into the soil. Series of pictures showing what the reader did after getting a few ideas here on how to water his large pine tree with buckets. You will have to fill the buckets two or three times each time you water to get the water deep enough in the soil to encourage deeper rooting. Don’t water again for about a week at this time of year; less often in winter and maybe twice a week in the heat of summer. Deep watering helps avoid the development of large surface roots that can heave sidewalks, driveways, walls and foundations. This type of system accomplishes the same thing as a drip system but with more work on your part and will be kind of ugly. But it will work. I would use about five or more buckets distributed under the canopy, about three or 4 feet apart. The more buckets, the better. The buckets are not made with UV treated plastic so you should paint the buckets or cover them so sunlight does not destroy them. Make the holes small. Five gallon buckets should run out of water in 30 minutes to one hour. The hole will eventually become plugged so you must clean it periodically. Use clean water a clean bucket and make sure you put a lid on top. Place the buckets on top of the soil or slightly buried. You don’t want to bury the buckets totally in the soil if the water is emptying from the bucket at the bottom. Most of the roots that take up water will be within the top 12 to 18 inches of the soil. If the bucket empties beneath this zone, the water will be released deep and not water the roots very well. In urban desert landscapes, trees should develop two types of roots; roots that anchor the plant and keep it from blowing over and roots that take up water and nutrients quickly. If trees planted in the desert are irrigated deeply, they will develop deep roots which will help anchor the plant in the soil. If they are not watered deeply but only receive shallow irrigations, they will not develop these deep roots. You can also help the tree get additional water by planting other shrubs under its canopy and overwatering them slightly to provide additional water for the tree. Surface mulch helps conserve water and encourages deeper rooting, particularly wood mulch.

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This Question on Drip Irrigation Made My Head Hurt!

Leave a Comment / drip irrigation, how many emitters, how often to water, how to irrigate, how to water /

Q. I have a LOT of different shrubs and trees on only 2 valves. I don’t know how to water them. The shrubs have 2 drip emitters for each shrub and they range from 2 each at 2gph (gallon per hour; gallon = 4 liters) for plants like photinia, red autumn sage, fountain grass, jasmine vines, rhaphiolepsis etc.; 2 each at 4gph for euonymous, abelias, boxwood, honeysuckle vines etc. The trees have more emitters. My landscaper told me to water 6 days per week for twice for 20 minutes each day (equals 4hrs/week). The nursery people advised me to water only 3 times each week for 45 minutes each day. Another nursery advised 6 days each week. So, what to do? My biggest problem is my 8 year old magnolia tree, trunk diameter about 5″, has 4 each a t 4gph emitters. It used to be very full, now it’s about 10 ‘ high; the leaves are dark brown, dry and falling off.  All help would be appreciated. A. You even confused me! In their defense I would have to say it’s possible that all three could be right. Because plants are adaptable to different situations there can be several right answers to one irrigation question. Nurseries are there to provide service, the best answers they can muster up. I am an educator so let me take a stab at it from an educator’s point of view. I would like to give you enough information so you can solve your own problem with irrigation. But in my opinion, two valves are not enough to give you the flexibility of different watering schedules with all your plants and different microclimates. Bear with me on this. Let’s all agree for the most part that as plants get larger they will require more water. Let’s also agree that large plants will use more water, and considerably more water, than smaller plants. The larger the plant, the more water it needs and should receive. Three irrigation valves. They are basically on and off switches for water. Irrigation valves are basically an on and off switch for water; when the valve is open, water flows. When the valve is closed, water stops flowing. Since you have one valve in the front and one valve in the back, these switches open water to all of your plants in the front at the same time and the valve in the back does the same for plants in the back. There are three basic questions that must be answered when irrigating; 1) how long to water, 2) how much should be applied, and 3) when to apply it. The valves basically solve the question how long to water (on/off). Button type drip emitter Flag type drip emitter. The drip emitters solve the question about how much to water. An irrigation clock answers the question when/how often to water. The irrigation valves allow water to flow a length of time and the emitters determine the amount of water applied to each plant during that time. The length of time the valve is open combined with the size of the emitter determine the amount of water delivered to each plant. This is where the confusion begins. To make it as easy as possible to irrigate let’s hold one of these variables constant. Arbitrarily, let’s hold the length of time the irrigation valve is open: one hour.  Just for the sake of argument. It could be 30 minutes, it could be 90 minutes, but let’s just hold it at 60 minutes. If we make this decision first, how many minutes to open the valves, it can make our other decisions much more simple. So we now agree the valve will be open for 60 minutes for our drip emitters. For me, this is a common length of time to leave the valve open for drip emitters. To determine how much water each plant will get we have to size our drip emitters; the gallons per hour we want to use. Because of plugging, it can be dangerous to give plants only one emitter. If that emitter plugs, chances are we will lose the plant in a short period of time during our extreme summer heat. Three different button drip emitters color coded for three different amounts of water per hour (gallons or liters per hour) To determine how much water to give the plant at each watering (or when the valve is on) we look at its size. The smaller plants of course require less every time the valve is on. So for the sake of argument let’s do this. Let’s give a plant 1 gallon of water every time the valve is open (in this case one hour) for every foot of its mature size. Example only! A very small plant may get 1 to 2 gallons.  A medium-sized plant may get 3 to 6 gallons.  A large shrub may get 8 to 15 gallon every time it’s watered. The larger the plant, the more emitters it will need under its canopy. A very small plant may require one to two emitters.  A medium sized plant might require 3 to 4 emitters.  A large shrub might require 6 to 8 emitters.  So now you will take the number of gallons you are giving this plant and divide it by the number of emitters you will provide for each plant. When you do this, you will determine the number and size of the emitters you will give to each plant. So for instance a medium sized plant may get 3 to 6 gallons at each watering delivered by 3 to 4 emitters. So the size of the emitters might be 1 to 2 gallons per hour. But I would keep all the emitters going to one plant at the same size.    It doesn’t make much difference if it’s one or 2 gallons more than you calculated. What is important is that you apply enough water during one irrigation to

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Determining the Correct Sized Drip Emitter

Leave a Comment / drip irrigation, how to determine the right sized drip emitter, which drip emitter to use /

Q. The landscape people are into variable drip emitters and think I am a little looney sticking to drip emitters.  How do you determine how many gallons to give large trees like African sumac, bottle trees, Swan Hill olives, Yew pines and chaste trees? A. No one puts it in gallons because there are too many different manufacturers and rates of deliveries of different irrigation emitters and sprinklers. These can vary from 1/4 gallon per hour (1 liter) to five gallons per hour. Then there are the types that are variable and can be twisted open to give you more or fewer gallons per hour. Drip emitters color coded for gallonage You have to figure make the conversion and convert it yourself. It is not terribly hard to do, particularly in drip irrigation. Each emitter is labeled or color coded to the gallons per hour that they emit. The hardest emitters to figure out are the types that can be adjusted (variable) to different amounts of water. Many of these are adjustable between 0 (shut off) to 10 gallons per hou It seems simple. You just twist the emitter open and it delivers more gallons per hour. But in actuality it begins to defeat the purpose of drip emitters: precision. Also many of these variable flow emitters are not pressure compensated. If it is not pressure compensated, then opening one emitter and allowing more gallons to flow can affect the number of gallons on all the other non pressure compensated emitters on the same line. Variable drip emitter This can mean you have to twist open or twist close each emitter along the same line perhaps multiple times to get the flow that seems to be appropriate. Not only that but these variable output emitters frequently emit so much water so quickly at the higher settings that it results in water puddling and running off to low spots. This is exactly contrary to the reason we should use drip emitters. With many different types and sizes of plants along the same line the next difficulty for most people is to figure out what size (gallons per hour) to match up with each plant along the line. So this is how I do that. The first thing I do with an emitter line attached to a single valve is determine how many hours or minutes the valve will be left open for watering. Frequently for drip irrigation the shortest time is one hour. Flag emitters easy to clean and color coded “Yikes” you might say because most people want to irrigate fifteen or twenty minutes. The problem with these short irrigation times is that it may force you to use the variable output emitters. Or it results in water applied so rapidly it does not penetrate the ground and instead runs and puddles somewhere else. Start with a minimum of one hour. In some cases you might water for two or three hours on a single line. What difference does it make? You are not standing there with a hose and it can take all night if you want it to. There is no problem watering at night with drip irrigation. Let it soak long, slowly and deeply. Try to use at least two emitters per plant in case one plugs. Here is the one hour example. One gallon plants, give them one gallon per hour (two, half gallon per hour emitters). Five gallon plants give them three to five gallons per hour (two, two gallon per hour emitters or three, one gallon per hour emitters). Fifteen gallon plants give them 8 to 15 gallons per hour (two, four gallon per hour emitters or two, five gallon per hour emitters or three, three gallon per hour emitters, etc.) Distribute the emitters under the plant canopy, one foot from the plant with distribution tubing and secure them in place with rock mulch or stakes to hold them in place. Emitters should be above the mulch so you can check them for plugging. Plants that are spaced closely together can and will get water from each other. Does this help a bit?

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Call Me Looney When it Comes to Drip Emitter and Drip Design

Leave a Comment / drip irrigation, how much water do trees use, how often to irrigate trees /

  Q. The landscape people are into variable emitters and think I am a little looney sticking to drip emitters.  How do you determine how many gallons to give large trees — like African sumac, bottle trees, Swan Hill olives, Yew pines and chaste trees? A. There are three things we have to consider when watering; how much water the plant needs, how frequently it needs it and the time of day when we will apply the water. All this needs to be entered into the irrigation controller. All plants of a similar size will be watered with a similar amount of water. Larger plants require deeper watering and more applied water In your example, you have two different categories of trees to consider; the desert trees like bottle tree and chaste tree AND non desert type trees like the African sumac, olives and yew pines. If they are all the same size then they will get a very similar amount of water. The difference in irrigating these two types of trees is the FREQUENCY or how often they are irrigated. True desert trees can be watered less often and should be. The nondesert trees can be watered more often.   If watered too often, many desert trees can have problems. If the soil drains of water freely then the usual problem we see is luxurious, unrestrained growth. Have you ever had a neighbor or friend brag, “My mesquite tree last year grew 8 feet! (i.e., I must be an extremely good gardener if I can get a tree to do that!). Well, my friend, it just means it is getting alot of water. Most desert plants respond to excess water by putting on lots of growth! As these trees get larger and larger, they will demand more and more water.   The smaller plants are easiest to do. I like to ask people, “What size container would you use to grow that plant?” Some people can visualize this while others have a hard time at first. Just think of the plants you see at the nursery. Generally speaking, I like to make sure the plant is getting at least half of the volume of its container to a maximum equal to the size of its container. It is better to estimate too much than not enough.  Different sized nurseery containers   (Disclaimer: nursery containers do not hold their namesake. For instance, a five gallon container DOES NOT hold five gallons. I know its dumb, but use its namesake anyway.)   You will apply all of this water in one hour. So if you need to apply five gallons of water, it will need to be applied in one hour. So the total amount of water applied to the plant would be five gallons per hour.   Then there are the types that are variable and can be twisted open to give you more or fewer gallons per hour. You have to figure make the conversion and convert it yourself. It is not terribly hard to do, particularly in drip irrigation. Each emitter is labeled or color coded to the gallons per hour that they emit “Flag” type drip emitter. Usually the flag allows you to turn it on or off, you can usually pull it to clean it, and the color refers to how much water it emits per hour. They are very simple to use, clean, inexpenive and accurate. I have used them in simple drip systems with no problems for over 20 years. There are also many others depending on your needs.   The hardest emitters to figure out are the types that can be adjusted to different amounts of water. Many of these are adjustable between 0 (shut off) to 10 gallons per hour. It seems simple. You just twist the emitter open and it delivers more gallons per hour.   I am sorry to you out there that like these emitters. I do not share the same feeling. When I see them, I just cringe. This is a variable output drip emitter that varies from “completely closed” to “I have no idea”. Landscapers LOVE them. Of course! It doesnt require any knowledge and no design is needed! Wonderful option for the ignorant. But in actuality it begins to defeat the purpose of drip emitters: precision. Also many of these variable flow emitters are not pressure compensated. If it is not pressure compensated, then opening one emitter and allowing more gallons to flow can affect the number of gallons flowing on all the other non pressure compensated emitters on the same line. This can mean you have to twist open or twist close each emitter along the same line perhaps multiple times to get the flow that seems to be appropriate.   Not only that but these variable output emitters frequently emit so much water so quickly at the higher settings that it results in water puddling and running off to low spots. This is exactly contrary to the reason we should use drip emitters. So you can see that I am not terribly fond of these types of emitters. With many different types and sizes of plants along the same line the next difficulty for most people is to figure out what size (gallons per hour) to match up with each plant along the line. So this is how I do that.   The first thing I do is determine how many hours or minutes the valve will be left open for watering. Frequently, for drip irrigation, the shortest time you should use is one hour. “Yikes” you might say because most people want to irrigate fifteen or twenty minutes. The problem with these short irrigation times is that it may force you to use the variable output emitters. Or it results in water applied so rapidly it does not penetrate the ground and instead runs and puddles somewhere it is not supposed to go.   Assume a minimum of one hour for the irrigation time. In some cases you might water for two or three hours on

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How to Water a Landscape With Two Valves (One front, one back)

Leave a Comment / drip irrigation, irrigation, irrigation schemes, size and water use, water use /

Q. I have a LOT of different shrubs and trees on only 2 valves (front & back). The shrubs have 2 emitters per shrub and range from 2- 2gph for plants like photinia, red autumn sage, fountain grass, jasmine vines, rhaphiolepsis etc.; and  2-4gph on euonymus, abelias, boxwood, honeysuckle vines etc. The trees have more emitters. My landscaper told me to water 6 days per week for 2-20 minutes per day (equals 4 hours per week). Star nursery advised me to water only 3 times per week for 45 minutes per day. Plant World advised 6 days per week. So, what to do?             My biggest problem is my 8 year old magnolia tree, trunk diameter about 5″, has 4-4gph emitters. It used to be very full, now it’s about 10 ‘ high & the leaves are dark brown, dry and falling off.  All help would be appreciated. A. You even confused me. In their defense I would have to say it’s possible that all three could be right. Because plants are adaptable to different situations there can be several right answers to one irrigation question. Nurseries are there to provide service, the best answers they can muster up. I am an educator so let me take a stab at it from an educator’s point of view. I would like to give you enough information so you can solve your own problem with irrigation. But you I think already realize that this is not the best irrigation setup for conserving water. You will have considerable waste even though it is on drip irrigation just because you have so few valves. Bear with me on this. Let’s all agree for the most part that as plants get larger they will require more water. Let’s also agree that large plants will use more water, and considerably more water, is one smaller plant. The larger the plant, the more water it should receive. Irrigation valves are basically an on and off switch for water; when the valve is open, water flows. When the valve is closed, water stops flowing. Since you have one valve in the front and one valve in the back, these switches open water to all of your plants in the front at the same time and the valve in the back does the same for plants in the back. There are three basic questions that must be answered; 1) how long to water, 2) how much should be applied, and 3) when to apply it. The valves basically solve the question when to water. The drip emitters solve the question about how much to water. Irrigation clock answers the question when to water. The irrigation valves allow water to flow and the emitters determine the amount of water applied to each plant. The length of time the valve is open combined with the size of the emitter determine the amount of water delivered plant. This is where the confusion begins. To make it as easy as possible to irrigate let’s hold one of these variables constant. Arbitrarily, let’s hold the length of time the irrigation valve is open to one hour. Just for the sake of argument. It could be 30 minutes, it could be 90 minutes, but let’s just hold it at 60 minutes. If we make this decision first, how many minutes to open the valves, it can make our other decisions much simpler. So we now agree the valve will be open for 60 minutes for drip emitters. This is how I typically determine an irrigation schedule for drip. To determine how much water each plant will get we have to size our drip emitters. Because of plugging, it can be a little bit dangerous to give plants only one emitter. If that’s emitter plugs, chances are we will lose the plant in a short period of time during the summer. To determine how much water to give the plant at each watering or when the valve is on we look at its size. The smaller plants of course require less every time the valve is on. So for the sake of argument let’s do this. Let’s give a plant 1 gallon of water every time the valve is open (in this case one hour) for every foot of its mature size. A very small plant may get 1 to 2 gallons. A medium-sized plant may get 3 to 6 gallons. A large shrub may get 8 to 15 gallon every time it’s watered. The larger the plant, the more emitters it will need under its canopy. A very small plant may require one to two emitters. A medium sized plant might require 3 to 4 emitters. A large shrub might require 6 to 8 emitters. So now you will take the number of gallons you are giving this plant and divide it by the number of emitters you will provide for each plant. When you do this, you will determine the number and size of the emitters you will give to each plant. So for instance a medium sized plant may get 3 to 6 gallons at each watering delivered by 3 to 4 emitters. So the size of the emitters might be 1 to 2 gallons per hour. But I would keep all the emitters going to one plant at the same size. So what if it’s one or 2 gallons more than you calculated. What is important is that you apply enough water during one irrigation to water the entire rootzone of each plant (plus a little extra to keep those salts in our city water flushed out of the rootzone). So now we have answered two of the questions; how long to run the valve and as a result of that how much water each plant will get because you have selected the correct size and number of emitters. The next and last question is probably the most difficult to answer. Remember, you have elected to set the time that the

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Watering Santa Rosa Plum in the Mojave Desert

Leave a Comment / drip irrigation, fruit trees, how many gallons, irrigation /

Q. I read your gardening articles faithfully, and I just searched your blog for some help, but I would like more information.  I just purchased a Santa Rosa plum, but I am not certain how much I should water it.  I haven’t yet planted it, and I want to make sure to give it enough emitters as it is located in the front yard which is mainly desert landscape plants and therefore do not require as much water as this will (I think).  Santa Rosa plum The tag indicated how much water in inches, and I wasn’t certain how to convert that into gallons.  Also, although there is rock mulch in the front yard, I am more than happy to remove that in this are to give the plum the best chance.  Is that necessary?  Finally, your article on planting fruit trees from your blog mentions a “slurry” but I don’t know what that means, and I wasn’t able to find a definition on your blog.  I would really appreciate some help.  Thank you.  A. Plums are not desert plants and should not be irrigated as if they were desert plants. Mixing desert plants with non-desert plants on the same valve can lead to watering desert plants to frequently or, the flip side, watering the non-desert plants not often enough. But this may be a moot point. In this town desert landscaping means surrounding any type of plant with rocks. This is kind of like calling tofu, meat. Just because people put rocks around plants does not make it desert landscaping but does give it the appearance of desert landscaping. Hopefully your Santa Rosa plum will be on a valve that has other drip emitters on it. The first thing to do is determine your current run time for that valve on your irrigation clock; the number of minutes or hours that station or valve operates. It will be more difficult to irrigate your plum if the valve irrigates other things on it that are not on drip. Drip irrigation is designed to give small amounts of water over long periods of time, usually hours. Other types of irrigation such as bubblers or sprinklers are designed to operate in minutes, not hours. Mixing the two together on one the valve makes it very difficult to accurately apply water to either one. I like to see true drip irrigation operate a minimum of one hour. Let’s assume that the valve for your plum will operate for one hour. (Now I am going to give you some misinformation and tell you a couple of lies so that I can make my point. I will clear up the lies and misinformation later.) So, if the plum was purchased in a 5 gallon container, then make sure it gets irrigated with 5 gallons of water in that one hour. If it was purchased in a 15 gallon container, then give it 15 gallons in one hour. As a tree in a 5 gallon container gets bigger, you will need to increase the amount of water applied to it in one hour to perhaps 10 gallons or 15 gallons next year. You can do this by adding additional emitters; perhaps a second one next year and the third one maybe three years from now. If the plum is really growing fast you may have to add emitters sooner. This is a judgment call. Mature plums at the Orchard are getting 30 gallons every time they are irrigated. This 30 gallons is applied once every 10 days to two weeks during the winter to as frequently as twice a week in midsummer. As it gets hotter, the frequency of applied water changes, not the amount per application. Let’s say you now have discovered a problem. The valve which will irrigate your plum runs for 15 minutes, not one hour. And everything on that valve is designed to be irrigated in 15 minutes. This means we have to enter the dark side of irrigation; bastardizing drip irrigation to get it to do something it was never intended to do. Adjustable drip emitter: the dark side of drip irrigation. Now we enter the realm of adjustable drip irrigation emitters. These emitters can be adjusted with flow rates of zero (shut off) to a lot. Oh, they like to say it is 0 to 10 gallons per minute but in actuality who really knows? I don’t care what they call it but this is no longer drip irrigation. But in some cases it will get the job done and you may have no other choice. Plants surrounded by rock mulch use more water than plants surrounded by wood mulch. Any type of mulch will help but rock mulch will get hotter than wood mulch and drive water use up. Some plants should never be planted in rock mulch. Your plum is one of them. Others include roses, lilies, Photinia, mock orange, heavenly bamboo and many others. It might be okay for a couple of years but I will guarantee its health will decline living in rock mulch after just a few years. Organic mulches like wood mulch will help your tree a lot. This wood mulch should cover an area not less than 6 feet in diameter around the plum tree and be at least 4 inches deep. Be sure to keep wood mulch a foot away from the tree trunk the first four or five years. There is 7 1/2 gallons in one cubic foot of water. 1 inch of water covering one square foot is a little bit more than half a gallon, actually 6/10 of a gallon. Since rain is measured in inches of precipitation and sprinklers are also measured in inches of precipitation per hour there is a tendency to give watering advice in inches rather than gallons. They leave it up to you to determine how many square feet you are going to irrigate. A penstemon might be irrigated over an area of

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