Seth, Will the faucet be the permanent connection for the irrigation to the trees? You could probably get away with flexible pipe on grade if there isn't much traffic in the area. Just make sure to secure it to the ground with u hooks so that if you do walk by you don't take yourself out! What kind of trees are they, that would impact how much water you need to get to them...

I hadn't meant to be abusive of Joe's points, just a counterpoint. Just a note about Urban Farmer's services, they are a full service irrigation store, and sell all the materials to install a conventional spray irrigation system as well. I would like to counter one of Joe's points, about drip irrigation being cheaper to install. I don't find that to be the case, in the systems I design and install, there is more hand labor involved to get emitter line to individual plants, so I'd say that the different systems are probably about on par or even slightly more expensive for a drip irrigation when using higher quality/more reliable fittings and materials. Also, as to the point about needing pressure regulators for drip systems, what is your point? The pressure regulator is not some expensive or elaborate device prone to failure, and even a conventional spray irrigation system will often require a pressure regulator at the valves if the house or street pressures are too high. Where drip irrigation excels is the benefits of using it on difficult to water steep slopes where spray irrigation would cause run-off at the higher application rates, and is not as good at giving deeper watering. You can also get away with using less valves with a larger area of coverage in a typical garden setting, because the water flows required are less volume and pressure. As to maintenance and repairs, I often find that clients with dogs and conventional spray irrigation systems may have more need of regular inspections to repair broken irrigation heads, especially if they conflict with a large dog running along an open metal fence at the street. As well, pop-up spray irrigation heads are equally prone to damage from autos driving over them or lawn mower blades clipping them, and when broken and set to run overnight, the wasted water will be far more wasteful than it would be with a lower flow/lower pressure drip system. I would not waste my time trying to convince someone who has their mind made up about their preferences in irrigation systems, but it is not as black and white as Joe would make it appear. Everyone should irrigate in a way that makes sense for their particular situation. I simply believe that drip irrigation in combination with micro-spray drip can create superb results while also using less water overall. Joe's contention that drip irrigation does not permit deep rooting of plants is only germane for those who don't run their systems long enough to wet the soil deeply. This is also very much a concern with spray systems as well, as most gardeners simply don't know how long it can take to deeply water a clay soil. Most spray systems will cause run-off in clay soils if watered for more than 10 to 15 minutes on a sloping site, and this won't wet the soil much beyond the first inch or two. Not to mention the water lost to wind/over throw spray, and evaporated water lost to the hot sun in combination with winds. In any case, both spray and drip irrigation design have their pros and cons, and the majority of residential homeowners are more likely to be timing their irrigation by schedules rather than plant needs, nor do most adjust their watering schedules more than once or twice a year to reflect the weather and seasons. In specifying which type of system makes more sense for an individual homeowner/client, it helps to weigh all the factors that should influence such a decision. While working as a landscape architect for a large firm doing subdivision homes for a developer, I had occasion to design a subsurface system using Netafim for lawns in this development. I can tell you that it drove the new home buyers crazy, as too many didn't trust that it was working properly, and would reset their individual home's irrigation controllers to vastly overwater the lawns, as they couldn't see it working. While it may make sense to use such a system for a commons area landscape that isn't subject to the whims of different homeowners, I wouldn't recommend it again for the average garden. The one place I would always recommend a spray system over a drip system would be for a client who can't control their dog's digging and chewing of things in the garden. A drip system will be much more vulnerable to damage in such a garden. I've also found that the most common animal damage to drip irrigation systems in my experience has been with squirrels chewing off the hard plastic mister heads I use in gardens which may have subtropicals such as bromeliads mounted on fences or trees. I've learned that the misters should never be mounted on the top of branches, but always on the bottom of a horizontal branch, to make it more difficult for the squirrels to do damage.

Brian, A larger line doesn't give you more pressure, only more volume. Your faucet coming out of your house is probably a 1/2" line operating at 60 PSI which is pretty common. Plastic pressure regulators aren't needed, IMHO, as you can effectively regulate the pressure with the faucet handle. Just another plastic part to degrade and fail in the hot sun. If you're setting up sprayers, go ahead and crack the sprayer adjustment enough so when you blow through it, some air escapes, then hook everything up and crank the faucet half way open and see how they're covering. The only advantage to high pressure is that the line pressurizes completely sooner than later. As an example, on one run I have eight sprayers, and about two dozen 1-10 gal emitters, and I run full pressure on the faucet, which is coming through a 3/4" galvanized nipple from a 1" PVC water line. The only time you run out of pressure is when you have a lot of large sprayers operating at max output, then they'll drop the pressure downstream quite a bit. Don't forget a vacuum breaker.

I am a drip irrigation hobbyist rather than an "expert," but I'll tell you what my experience has been. 1) For one, I would certainly put the backflow-preventer, filter, and pressure regulator downstream of the timer, as there will be additional pressure losses through the valves and turns of the timer. So yes, that means a backflow-preventer, filter, and pressure regulator for each line, in order. I actually had high-quality hose bibs with built-in backflow prevention installed about a decade ago during some remodeling work, so now I only need a backflow device if working on a system for other people. Many municipalities are requiring backflow prevention hose bibs to protect the water supply from contaminants, so this might be something to consider as well. 2) So yes, by using the pressure regulator after the timer, lines 3 and 4 can be attached to regular garden hoses at full pressure. 3) I routinely use high-quality garden hose (contractor-grade hoses, or Craftsmen black all-rubber hoses) to transport water to my drip irrigation systems that are 100' or more from my water sources. Since you are limited on the run-length of the 1/2" poly tubing due to static pressure loss along the length of the run, using a garden hose to get to the area to be irrigated is the only way I know how, short of installing a new water line. -Kris