We tried drip irrigation, but it did not work in our garden. The water went straight down immediately, and no matter how long it was on only wetted about a 3 inch diameter circle of the soil. We have changed it all out for either soaker hoses for where there are lots of plants, or, using a similar idea, putting little low volume sprinklers under individual plants - at least they throw out water up to 12 inches.

Jackie

There is a fair amount of relatively simple math involved with these things. Then you go on to fine tune for your individual garden.

How much water, in gallons, do you want a rose to get a week? Divided up by how many times you want the water to go on. So if you want to give each rose 12 gallons a week, divided up into 2 watering sessions, You want to give the rose roughly 6 gallons at a time. In order to get that 6 gallons with a standard 1 gallon/hour emitter, the emitter has to be running for 6 hours. Alternatively, you could have 3 emitters running for 2 hours for the same amount of water.

The tricky part is that different soils disperse the water differently. Sandy soils tend to have the water go more down than out. Heavier, clay soils do the opposite. So the usual recommendation with sandy soil is to have the irrigation run more often for shorter times, so the water doesn't just run below the reach of the roots. With clay soil, it may work better to water in one big dose so the soil gets thoroughly wet. Unless you are willing to do a lot of exploratory digging with a trowel, this is the trial and error part.

What mad_gallica said. The emmiters create a wet cone whose angle depends on the soil properties. However, there are different kinds of emitters. For sandy soils one would want to use an emitter which disperses water in an umbrella fashion (mini sprinkler like) covering a larger area instead of an emitter that drips straight down. There are also emitters with adjustable flow and pressure compensating emitters for where you have changes in elevation along the line. Emitters performance (both flow and coverage) depends on pressure (so they depend also on line diameter) and the good ones come with a flow diagram which shows flow per hour depending on water pressure in the flow line.

Regardless of the above, plants adjust to the emitters so covering the whole root area, while desirable, is not a must.

Just as an example here is the specs of the emitters I use. I'm sure similar products can be found over there. You can see the different kinds of flow characteristcs and coverage shape. These tech specs use the metric system of course (1 gallon is approx 4 liters, 1 bar is approx 14.5 psi) but one can get an idea of the different emitters available and how pressure affects their performance.

Emitters

Hi Ingrid, I'm hesitant to offer advice because I'm not sure that our situations are similar. I have a drip irrigation system for all my roses and, apart from the roses I planted in March this year, they all survive on just the drip irrigation - and whatever rain we get.

I have about a hundred Queen of Sweden roses in my hedge and each bush has two 'drippers' that deliver 4 litres of water an hour - so each bush gets 8 litres (about 2 gallons) of water in an hour. The hedge is in full sun all day and doesn't receive any shade whatsoever at any time of the day. I have a thick mulch of dried grass clippings under the roses and the irrigation hose is also under the mulch.

I run my irrigation system for one hour, twice a week. Since the beginning of July we have had temperatures over 34 degrees (93F) every day - two weeks ago we had a storm that delivered us 15 mms rain and today we had the same amount from another storm. Normally, we wouldn't expect to get rain before the end of August so we've been lucky in that regard.

The roses flowered wonderfully in spring and have just finished their second flush, however, this last time the flowers, although almost as prolific as in May, were less than half their normal size. Tomorrow, I'll make a start on dead-heading and then I'll feed the hedge and keep my fingers crossed for another flush of full sized roses in autumn.

My soil is heavy clay (which has been amended with lots of well rotted horse manure and good quality soil and the mulch is renewed each year, too). The drippers do appear to only water a small circle of soil but it seems to be sufficient to keep the roses growing strongly and - apart from this past month - flowering well too.

Hope this helps

Tricia

It might help to put in an emitter in an area you plan to put a rose in and run your system. Wait til the next day and use your shovel to see just how far the water spread

Instead of having the emitter attached directly to the 1/2” feed line just attach 1/4” line of any length then the emitter. That allows you keep the larger line outside the garden with only small lines running to each plant. Should a plant be moved all you have to do is move the 1/4” line over to it.

By including a valve inline between the feed and the emitter you can fine tune the amount of water delivered to each plant. You could even run a 1/4” line down a row of plants with ’T’s wherever it meets a plant, then a short 1/4” length of line followed by the emitter. Up to 20 plants can be handled off one 1/4” line.

They also make 1/4” soaker hose. Run a 1/4 inch hose from the 1/2” line out to the plant, install a ’T’ at the end. Then attach both ends of a 1/4” soaker hose to the T thus forming a loop around the plant. Again, if you include a 1/4” valve inline you can adjust the volume delivered.

Pressure regulator on the valve helps a lot.

Soaker hose clogs pretty fast in So Cal with the water being so hard.

Do what kippy said, put an emitter somewhere, run the line, wait until the next day and then dig to see how far and deep the emitter has wet your soil.

The more emitters, the more evenly distributed the root system will be.

Your comments have been so helpful, thanks so much. We tried several different variations and finally decided to use one long hose and then little feeder hoses without anything on the end, one for a small rose and up to three for larger plants. Since we have porous soil we'll run the water more often but for shorter periods of time. The ends of the little hoses will be put under the mulch, as Tricia describes. The emitters that go around in circles, which we also tried, wet the mulch rather than the ground underneath. For the rectangular area with lots of roses, the large hose will be in the back, against the house wall, and feed lines of varying lengths will be directed to each rose. We're not using emitters since the feed lines will be under the mulch. We basically just need to determine how long to run the system and how often per week. For our porous soil I think we'll run it for a minimum of three times a week if it's not raining and see how the roses and other plants do. It will be interesting to see whether our water bill increases, decreases or stays the same. I'll still use the garden hose once in a while to give the plants a bath and spray off aphids and dead leaves. I'd like to hear from anyone who thinks this is not a good plan or that we're not aware of a more efficient way to do this.

I use inline drip irrigation with emitters spaced every six inches. It also comes in twelve inch spacing. My soil is a sandy clay. Anyway, with this scheme each rose has multiple emitters circling it, none less than 3 or 4. I did not calculate the amount of water, but I run the irrigation for 45 minutes, then repeat an hour later, and do this every ten days. Breaking up the time like that is to insure that all the water is absorbed and none of it runs off down the hill. A few of the roses look a little parched but none have died, and the midsummer flush was as abundant as it ever was. Established climbers on the fence get the same amount of water but only every three weeks. Some in between areas are on an every two week cycle. There is mulch on top of the emitter lines as well as the empty ground between plants. I want as little water to evaporate as possible.

I should mention that newly planted or transplanted roses and perennials get supplemental hand watering for the first month or so, and maybe longer a bit if I remember to do it. Plants that don't make it, just don't make it. I am astonished at how well most of them are doing.

I decided that roses that could not get by on the water I can afford to give them cannot live in my garden. So far most of them are doing fine.

Our water usage is down 20+% from the year before.

Rosefolly

Running a 'drip' irrigation system without the 'drip' part, i.e. using just the lines without emitters, kind of defeats the whole idea of using drip irrigation for saving water. The idea of the emitter is to have accurate control of the amount of water you disperse to each plant and the idea of the 'drip' is to avoid too much water loss due to evaporation and allow enough time for the water to soak in (the second one obviously not applicable in very porous soils). Not using emitters sounds to me as just a more convenient way of watering the plants than carrying a hose from plant to plant. Also I'm not sure why you could not use emitters under the mulch. Having said this, running the lines without emitters may not be a bad idea in a very low pressure system. If this system is connected to the main communal watering supply though, the pressure will not be low.

PS. Please do not judge the efficiency of the emitters by looking at the soil surface. There is always a cone formed in the ground with the its tip at the emitter point. The whole idea of the drip system is NOT to fill the watering hole with water, not flood the site, but saturate the soil at the root level often leaving much of the surface area appearing dry. Root level can be anything from 6 inches to more than a foot deep. This limits loss of water due to evaporation. The angle (width) of the cone does depend on soil properties so one has to dig a bit to see the efficacy of a particular system. A test site as others suggested is the best way to check this. I have been running a dip system for 30 years and I have never found a situation where it can not be made effective. My soil varies from clay to porous sand ammended with organic matter so I have good experience in varying soils.

Tea Rose Row seems to have a slight elevation change and I've noticed that the plants on the slightly higher part have quite a bit less water coming out than those more downhill. Is there some way to fix that? There also seems to be leaking of water in some areas where the main hose connects to the smaller lines. It seems that this system is not quite problem-free, and that we have a lot more to learn. Nik, I'm not sure I understand how the emitters control the amount of water you disperse to each plant. Ours are very small and don't have a control mechanism but perhaps larger ones do. It may be that the system we have is not an optimal one for our needs.

One needs to use so called pressure or self compensating emitters in inclinations to avoid uneven distribution. Ingrid, each emitter is specd to disperse a controlled amount of water per minute (or hour) depending on line pressure. There are also emitters where one can regulate discharge within a certain range (again depending on pressure) by turning a cap or something. If you take a look at the spec sheet I have linked to above I'm sure you'll get the rough idea even if you can't follow the technicalities. With regards to water leaking, this should not happen if correct diameter joints have been used for connecting the main to distributing lines and they have been installed properly. I can't help you with specific products available in the US but I'm sure either a google search or a professional company can help.

Thank you, Nic, for the further guidance. I did look at your spec sheet and, being a girly girl, quickly became overwhelmed. I think hubby will do better with it. You've been so helpful.

I have tried many different configuration when it comes to drip irrigation. I used to use variable flow emitter on spike. My soil is sandy and I found the emitter to be inadequate as the wettable area is very small. Plus, I still have to hand water the weekly fertilizer. Next I tried micro sprayers, one per bush . It worked better ,especially because I have so many perennial fillers between roses, however they used too much water and the water did not necessarily go where I need it to go. Plus my perennial rotted from too much wetness. I used granular fertilizer this time. The problem now is that the rose bushes get too much fertilizer at the beginning of the month and not enough at the end of the month. Next I tried 1/4" line with emitters built-in. I circled the base of the bush. Then I realized that the area under the trunk of the base is completely dry. This week, I modified it again. I have 1/4" line going to each bush, then I connected it to 1/4" with built in emitters (every 6", each cut section has about 7 emitters). The end of the line is plugged with adjustable emitter.I circle the bush with the built-in emitter line and place the end with the adjustable emitter at the trunk of the bush. The odyssey continues....

That sounds like a great solution SSS.

Ok Ingrid. What you need is pressure compensating in-line dripper tubing. it is 1/2" wide pipe, it's brown, and it has two holes on opposite sides of the pipe every foot. The emitters are built into the pipe, so you can see small lumps every foot, but all you can see from the outside is a little hole.

Specifics - You need to buy the pressure compensating version due to the change in elevation along your line. You can usually choose how far apart each dripper is within the tube - usually a choice between 6", 12" or 18". Since you have free-draining soil I would recommend getting the one with 6" intervals between the build-in drippers. You can also choose between how much water each dripper let's out per hour; in Australia you can usually choose between 2, 3 and 4 litres per hour (don't know what that is in gallons). For free-draining soil, I would recommend the one that releases 4 litres/hour.

Conventional wisdom here suggests watering for 45 mins thrice per week when using 4litres per hour drippers in sandy soil. This might be a good starting point for you. (Please note - I think water is a lot cheaper here, and a lot of Aussies irrigate with rain water from tanks anyway).

There is company called Netafim that make a good quality pressure compensating in-line dripper, and I think that brand is available in the US.

in your area, you will need to install it underneath the mulch. There's no point using micro sprayers where you are because they'll just water your mulch. Then the sun and hot climate will dry out your mulch.

What muscovy refers to is something like this
Pressure compensating dripper lines

Here, instead of having pressure compensating emitters you have the emitters built in the line in regular intervals. One can do the same by using individual pressure compensating emitters at lower cost ( I think) as I suggested above. What the problem with any dripper line is that if you have to water bushes separated by an area which is not to be watered (a shrubbery), the line has to be cut into suitable pieces and attached to the regular line at the points where the bushes are. Otherwise you end up watering the dirt. Dripper lines are really designed for applications where there are rows of plants planted at regular intervals (e.g. as in an agricultural field or a greenhouse).

Yes, what Nik says is right! If you have a tree here, a bush there, and a lot of gravel or mulch in between, you'll want is install individual pressure compensating (external) emitters to plain poly pipe only where required.

I get warm weather and quite a lot of rain in my garden, which means a lot of weeds :) So I try to plant very very densely with heaps of layers so there's no room for weeds! (That's the plan anyway). Since all my beds are very heavily planted, I will be installing the in-line dripper that I referred to. Of course,this will be a huge waste of water for more sparsely planted gardens (it's late winter here and a jungle of weeds, so I kind of forget that sparse gardens exist!)

thanks Nik for pointing this out!

I agree that irrigation systems are wonderful. Ours has 4 controllers with 6 stations on each. We have 2 water services (because we live in and own a duplex), so we get to run water from both of them simultaneously. The system goes on automatically for several hours (1 station at a time) twice a week, starting at midnight so that water does not get lost by evaporation, and it does not annoy the passers by. Most of our pots are even on it, but of course not all, because I keep adding them faster than my DH can add them to the system.

I think over time you will notice more and more how deeper roots benefit the roses as well. That was a lesson we learned in the past, plants that needed almost daily watering had a hard time with the heat because they had shallow roots, the ones on drip had deep roots and it did not bother them as much. That said, with the heat wave here, I can tell the plants who have good roots from those who struggle and I may have lost a couple that just were not able to deal with the week of heat

That's great news Ingrid! Have you had a water bill yet to see how it compares to normal hose watering?

I don't have a definite answer, muscovy, since our payment cycle is from the middle of the month to the next middle of the month. The next payment cycle should be more accurate since all four weeks will be included, which is not the case now. I'm quite anxious to see what the difference is. Even if water use doesn't decrease I'll be satisfied since the roses that are on the drip system have faster and more growth than anything else in the garden. We're now putting in some more drip systems in different areas, and it won't be until all that is finished that we can do a more exact comparison of pre- versus post-drip prices.

I really wish we had thought to do this much sooner, which is what everyone recommended here. My husband has begun on the triangular plot in the front and, after some experimentation, has decided to go with two lines rather than one for more uniform coverage. I continue to be delighted with all the new growth and buds of the roses in Tea Rose Row, in spite of it being late summer and having been through a few days of killer temperatures. The older leaves feel the stress and turn yellow and fall of or, even worse, hang on, but all the time new leaves and buds are forming. It's a real garden high for me! I can't wait to have all the areas done, by which time we will probably have El Nino and won't need any of it!

You'll never regret your drip system, Ingrid. I couldn't have any kind of a garden without it. I hope you see the wonderful improvement it should bring your plants without a big boost in your bill. Congratulations. Diane

Yay Ingrid! I'm very pleased for you :)

Ingrid,

Do you have a dripper unit at the end of each 1/4 inch hose or are the lines open?
If open you may be wasting a ton of water if you leave the water run for a long time. To check how much is going to each plant I suggest you put the line in a bucket and see how fast it fills up. Do this at the first and last lines so you will know if there is problem with pressure.

If each line has a dripper attached then I suggest you connect everything up to a timer, back flow preventer, pressure valve, followed by a filter unit, and forget about watering each day. Let the timer turn the system on and off….. until El Nino shows up that is… lol

toolbelt, it seems Ingrid is running the lines open and is using multiple lines per bush. I commented on that several posts ago but the user is the final judge of the efficiency of a system. Personally, as I wrote, I would not recommend this unless one is using a very low pressure system (e.g. gravity fed from a raised tank or something). Otherwise it seems to be the equivalent of watering by hose, it saves you only physical energy.

I can't yet comment on the cost of this system, but can only say that even with the heat wave we're having the roses that have the drip system are chock full of young growth and buds. We put the system in a new area just recently which we call the front triangle bed, and I was simply astounded that in literally two days I saw new growth coming out where none had been there before. The soil is very porous so I don't leave the system on very long but with so much heat lately I have done it every day. I'm not saying this system is as perfect as it could be but it is superior to using a hose because there is much less flow through the thin hoses but for a much longer time than would be the case if I were standing there with a hose, and the results speak for themselves. Roses like Mrs. B.R. Cant, of which I have two, literally did not show new growth, much less bloom, for months before we put in the drip system. In fact, branches were dying back and I was contemplating removing these roses and putting in some drought-tolerant plants. Now both of them have new growth and buds, even though the temperatures are as high, if not higher, than before. I can only go by the empirical evidence of what I see, and the change has been dramatic. However, I really like toolbelt's advice of putting the beginning and ending lines in buckets to see how much water is being used. Thanks for the tip.

One thing I have learnt about drip irrigation is not to have "dead ends", by this I mean ends that just stop and blocked off. Even on a slope I continue the pipe around till it meets it's self and join it. This makes the same pressure in the entire line, which makes the drippers work at the same rate, hope this helps in some way.

David.

That's very interesting Dave, since unfortunately we do have dead ends that are blocked off. I'll definitely mention this to my husband who is the one putting this together. So much to learn, but since there are three large areas still to do this is helpful information. He may have to redo the two we already have. Thanks for your input.

Hi David, I'm certainly no engineer and the facts about hydraulic pressure and the like had always been confusing but what you're saying sounds strange to me. I feel there should be any difference in the system's pressure either way. I might very well be wrong so I would welcome somebody with more expert knowledge to chime in. What I know for a fact though is that in large scale agricultural applications there seem to be lots of dead ends and no one seems to mind.

What you may have experienced is the creation of air bubbles in the system which end up being 'squeezed in' the parts of the piping which lie at the highest and are dead ends. If this happens a lot then the sipmplest thing to do is to install an additional emitter at the very end of the line. This will help vent the air out and will help the rest of the emitters work properly. There are flush valves and such things that can be used but this is becoming too much for a home project.

To prevent the system emptying out through the lowest emitters when the valve or tap closes, check valves can be installed allong the slopping line which will keep some water in the system at all times. This helps avoid the bubble problem and also helps avoid overirrigation of the lowest points by the system emptying out to that one spot.

I have found the following very useful to help grasp the basics

For slopes
Drip Irrigation Tutorial

Hi Nik, this is a bit from your reply,

"Hi David, I'm certainly no engineer and the facts about hydraulic pressure and the like had always been confusing but what you're saying sounds strange to me. I feel there should be any difference in the system's pressure either way"

The idea of having complete circle give you a constant flow from either end, if you have one "weak" emitter in a dead end line the plant that is near it will suffer. The reason I mention this is we had 363 driplines in the vineyard and found that some of the "inline" drippers were not doing thier job, so we linked all the ends and had constant flow/pressure thru out the vineyard blocks.

With my personal use of irrigation, I buy blank polypipe and pace two emitters, one either side of the rose and run the poly in loop within the garden.

A piece of trivia about water/drippers. When the water reaches the ground it starts off as a drip then as time goes by it forms bell/teardrop effect under the soil and if left long enough it connects to the one next to it. This happen in the common garden as well, but this depends on the soil type.

David.

Hi David,

I'm sure that has been your experience (about connecting the ends) but maybe there is another explanation why it worked better for you? Maybe the system was not designed with mainline(s) of adequate diameter in the first place so connecting the ends just solved that problem by effectively providing adequate flow? Or similarly the each branch line is longer than it should, so by connecting all the ends together the effective length is shortened. That should not be the case if the system is properly claculated in the first place. If one designs a looped system it is much more difficult to calculate it properly.

As I said, I see no reason for 'pressure equalization' due to the connection of the ends in a circle. It should not make a difference in a hydraulic system, but, as I also said, I'm not an engineer I'm attacking this just with high school physics.

David, is that you, just with a different user name? Hi if it is!

Nik, if this is David from Mudgee, then he definitely know his dripper systems. We've had lots of talks about it on our private forum which I didn't really understand, but that David and his pals have been helping me set up an irrigation system at my place.

i don't understand the physics behind it either, but those guys do. Hopefully they will be able to explain it to us here.

I can only be convinced by an equation. Preferaby complex so I will need to spend ages to understand it... I said I'm not an engineer but I didn't say I'm mathematically too challenged..

Fortunately this fascinating discussion is strictly academic for me since our very simple and basic system is working beautifully, probably because our property is carved out of the side of a hill and the part that contains the house and garden is mostly as flat as a pancake. David, what I did find interesting is your explanation of how a drip system has a teardrop effect under the soil and how the pools of water might connect with each other. In some areas the plants are planted fairly closely together and I can see how this would allow the roots to spread out and foster the development of healthy plants, as long as they don't actually crowd each other.

These are pictures of Tea Rose Row which is on a drip system. Please keep in mind that we have had temperatures of 102 and the high nineties for at least the past week. Before drip nothing it this area was blooming and there was no new growth. The small rose, Carefree Beauty, between two barely visible large tea roses, had grown very little before drip and now has new growth and buds that I have to remove almost every day. The tea roses on either side have expanded to begin to fill the empty space which at one point I thought would never happen. The other small rose is a young Souvenir de la Malmaison, also on drip in the triangle area, which is not only growing apace but I'm removing buds on a daily basis. For some time now I've had the drip system on every night for about an hour and the result has been phenomenal. However, depending on the next water bill I don't know whether I will be able to continue to maintain that regimen. It may not be necessary once the extreme heat abates.

Hi Zoe, yes it is me/myself

Ingrid, that is an amazing change in the garden. As for the teardrop effect, we know this works as we dug a 3mt/10ft trench beside a row of grapes and it was shown very visibly. Roses do not set roots as deep as grapes, but what we have learnt, is to soak the ground so the profile is wet/damp and to just maintain the area moist.

Also a bit of trivia Ingrid and others, it has been found that roses take up food twice daily(no science), 11am and 1pm.

Nik, I will get some info from our water engineer/Netafim reseller.

Ingrid, that's wonderful. My main reservation, as I have already expressed it, is that you don't use a drip system in the strict sense of the word since you don't use emitters. I worry that you use more water than you have to with water being wasted by going too deep beyond the feeder root horizon. One additional thing one has to keep in mind when (if) using too much water is the fact that movable nutrients such as nitrogen are quickly flushed out beneath the root zone, so one has to compensate by fertilization. This is more common in sandy soils like you have over there. I have personal experience of this since I have to flush every now and then since I use my well's hard and alkaline water for irrigation. Flushing causes nitrogen to move beyond the root zone with signs of chlorosis being evident during the next growth spurt.

At some point you will have to do some probing to check out if you water too deep, wasting water. Rose feeder roots are shallower than retaining roots. I don't think there's much point in wetting to a depth of more than 12 inches or so in the case of roses but maybe someone knows better about this.

The ground has been dry under a few inches of surface moisture for a very long time and I think that's why I'm now seeing such an explosion of growth and bloom. After some time I will begin to study how much or little water the roses need, but at this point I think at least some of the roses have been short of sub-surface moisture for quite a long time and giving them more than necessary for a little while will not hurt them. Strangely, our water district actually has a surplus of water in its reservoirs because they've been importing water (don't ask!) so I don't feel that I'm causing any harm at this time, especially with El Nino coming soon. There will be quite a bit of fine tuning needed in the future to ensure we don't waste water but that the roses still receive the amount they require.

@Nik

That is so true in my case. I have sandy soil that doesn't retain moisture well. I compensated by watering frequently, sometime using garden hose, sometimes using micro sprinklers. I fertilized frequently, sometimes twice a week using the water soluble fertilizer at 1/4 strength. My roses never look healthy; even when the leaves are green, there is always that yellowish cast to them. I have now re-set up the irrigation using the in-line emitters as well as micro tubing with built-in emitters. Hopefully this new setup will help save the roses that I still have. A question..Just how big is a rose's rootball?

sun_sky_sand, if I may ask one Q, if you go and grab a small hand full of your "sandy soil" will it make a "cake/egg shape" in your hand and stay that way ?

David.

I have been mulching with grass clipping, oak leaves and bagged mulch. The planting holes are amended with composted manure, garden soil and peat.

SSS, your amendments to the soil look really great! I can see it was very sandy before :)

Nik, I don't have any formulas for you I'm sorry, but I seem to recall the argument had a lot to do with friction loss. I had thought that because friction losses were reduced you could a) use a smaller diameter dripper pipe without losing pressure, or b) use the same diameter pipe but over longer distances without losing pressure.

i remember thinking that this made sense to me because if, for instance, you had 50m of dripper with a dead end, then the dead end (furthest point from the inlet) would be 50m from the inlet, but if you had 50m in a loop, the furthers point from the inlet would only be 25m away.

but I know absolutely nothing about physics, so this reasoning might be totally flawed!

David,

I think what you're saying now is exactly what I said earlier on...

I said: 'Maybe the system was not designed with mainline(s) of adequate diameter
in the first place so connecting the ends just solved that problem by
effectively providing adequate flow? Or similarly the each branch line
is longer than it should, so by connecting all the ends together the
effective length is shortened'

If the system is properly calculated in the first place you don't need to loop it around. Looping can cause turbulence, increase the friction losses and makes the circuit more difficult to calculate vs a layout with dead ends but of adequate diameter for its size.

Sorry Nik, it's me, not David!

I only have have a half acre back yard that I'm looking at irrigating, so I don't really have any experience doing proper calculations and the like. I also don't know a lot about physics! That was just my understanding of the possible advantages of looped systems.

Perhaps they might only be beneficial in backyard applications like mine for the very reason you've suggested - that the pressure and length calculations are not always designed properly (or at all!) in DIY backyard installs.

Oops confused... sorry. In any case, I think that if looping a layout seems to improve it, then it will be better to redo the layout by splitting the lines or use larger diamerer lines. The drip irrigation tutorials I linked to above seem a good starting point.

Yes, I liked those tutorials as I'm more of a visual person than a reading person, so I liked the diagrams.

ingrid and SSS, do have a look at the turorials when you get a moment. Very good info there and a good starting point.

Does anybody have suggestions, from experience or from other sources) about the rough water volume requirements of established rose bushes during hot periods in a dry climate? Say California for example. I know these things vary a lot with many factors (mainly climate, sun exposure and size of plant) but are we talking about 5 galons per week or 50?