Agree. While there are numerous discussions here about using drip irrigation systems and they include links to several recommended brand names, all the various kits have disadvantages one has to compensate for. Rainbird makes several different kits so a link to the one you are considering would be helpful.

"okay to tunnel the 1/2" tubing in the grass? And how deep?"

No, you run a regular garden hose from the faucet to the bed, screw the pressure reducer to the end of the garden hose and connect the the 1/2 feeder tubing to it. The 1/2" feeder tubing goes in the bed itself and is covered with your garden mulch.

Soaker hose are not only less expensive but more effective, more flexible for planting layout, and easier to maintain.

Dave

https://www.gardenweb.com/gardenweb/query/drip-irrigation

Keep in mind that soaker hose is cheap and easy to cut off and configure to specific beds if needed. Depending on your water pressure, you probably will want to feed the soaker from both ends, with your bed configuration, garden hose, y splitter and a 25 foot hose for one bed. A "wiggly U" which as pointed out previously, is easily reconfigured as you get into succession planting. If you want to get hi tech, a mechanical water timer for $10 is state of the art. :-)

One thing I figured out about watering and gardens is that a garden or bed is like a sponge, sure, you can "drip" in particular places, but the water is going to migrate all over, so why fight it?

Dave, where would the back flow preventer go? At the faucet?

There is a 75 ft between the faucet and the raised bed. Trying to come up with a solution to bridge the gap. Garden Hose to pvc pipe underground to 1/2 tube at the bed?

You could bury a pipe or do what I do, wind up hose reel, once a week or so unwind, give area good watering, wind up hose. You don't mention where you're located, but most places do get rain during the growing season. The old rule used to be one inch of water per week. Too much water can be as bad as not enough. If you've got adequate mulch should be fine. No backflow preventer needed. Depending on type of soaker hose, a separate pressure reducer may need to be connected between the source and the actual hose. Other soaker's have a plastic disc with a small hole in the center of the soaker hose coupling which provides the pressure reduction. Go over to youtube and enter soaker hose and you'll see various types, styles, and configurations.

Dave, didn't mean to steal your question, but thought it "flowed" well. :-)

I have drip and didn't purchase any kit, I bought the parts individually from different manufacturers to suit my purpose.

I went to a local garden center and Amazon and bought 3/4" black irrigation tubing. Used zip ties to crimp one end, and tubing-to-garden hose connector/adapter at the other. I have a timer and buried the irrigation line so it's not visible.

Boughtsome 1/4" irrigation lines with 6" between drip emitters. Used a drill bit to poke holes and a packet of 1/4" barbed connectors and goof plugs in case I mess up. Also some 1/4" valves so I can control output of each irrigation line.

Overall I'm happy with my choice. I've planted some fig and grape and poked a hole in main distribution to run a blank line with emitter to it. I like the flexibility.

If you go with drip, make sure spacing of emitters suit your needs.

Back flow preventer goes on the house faucet (assuming the house isn't already protected). Purpose is to protect house water system from backflo contamination. The pressure reducer then attaches to the preventer.

"Trying to come up with a solution to bridge the gap. Garden Hose to pvc pipe underground to 1/2 tube at the bed?"

Easiest - a 75 foot heavy duty garden hose just laying on top the ground to feed bed system. Next easy would be to just bury that same heavy duty hose (or PVC pipe) 2-3" down but that depends on your climate and soil frost depth and the traffic over the area. This wall PVC won't hold up to heavy traffic over it. Or you can pay a plumber to install a deep trenched-in faucet (freeze-proof) out by the garden.

Dave

Dave, I don't have to worry about chemical leeching from the heavy duty garden hose material, into the water? This does sound like the easiest option. it would be a 50 ft run along shrubs, then a few inches in my lawn, so the mower doesn't go over it.