for a garden plot in rows, I prefer a drip tape type system like T-tape
http://www.deere.com/en_US/water/productsequipment/products_ttape.html
and since I use it 3 or more years in a row, I like the heaviest, either the 510 or the 515. (I use the 515, 8 inch spacing, 0.51 flow rate)I lay this on top of permanent beds and just mulch over it then lift it back on top of the mulch each season.
for trees and such, I like the no-clog emitters at the bottom of this page.
http://www.dripworksusa.com/store/drippers.php#DMIL12
I use the 2, 3, and 5 gpm on different lines for different reasons. do NOT mix different kinds or different flow rates on the same line. If you need different amounts of water, use a lower flow and double or tipple up where you need more water.

I have a drip system connected to the hose bibb in the backyard. Hose-end timer to an adapter to 1/2" poly tubing that goes to the garden. It then branches off into 1/4" tubing with 0.5GPM in-line drippers. I also use 1/4" tubing with built-in emitters (Toro). Both seem to work well.

I use 1 emitter for most plants, but may use 2-3 for larger plants.

I use the 1 gallon/hour/foot drip tubing, either in a spiral with the coils about a foot apart or in lines about 18 inches apart.

It makes the water distribution under the mulch very even and the roots spread all over the beds.

Thanks everyone. I just picked up a pack of 1 GPH emitters. That should be enough to cover two of my growing areas. I have some of the no clog type that softmentor mentioned. I'll use those for my third growing area.

lazy, How long/often do you typically water with the 1 GPH drip tubing?

Right now I'm watering every other day for 20 minutes (AM and PM). As it gets hotter I'll increase the time.

Just an FYI, Home Depot and Lowes sell entire starter drip kits for round $20.

"do NOT mix different kinds or different flow rates on the same line."

Whats wrong with this?

I have many 1gph shrubs and plants on the same zone/line as other trees on 2gph emitters.. (some trees have 2 lines running to them with 2gph on each line, other trees have 2 lines but one is 2gph and other is 1gph... with my shrubs all at 1gph)

Also my raised garden is set up on this same zone, each plant (about 6 or 7 plants) has its own 1gph flag emitter. I run the timer for 2.5 hours twice a week right now, then later Ill switch to 3 hours or so, and maybe do 3 times a week when summer heat starts to kick in

"I use the 2, 3, and 5 gpm on different lines for different reasons. do NOT mix different kinds or different flow rates on the same line. If you need different amounts of water, use a lower flow and double or tipple up where you need more water."

Mullenium - You are right, the person quoted is wrong.

Look at the planning guides from Toro or other drip system makers. The way to deliver different amounts is to figure out what will water the least demanding plant and then use more emitters or higher flow emitters for the others.

Just don't exceed the limit of the line to deliver water, (it's about 150GPH if I remember correctly, so keeping it to 100 gallons of total emitter gives you plenty of margin.

Well, if you are doing ok with mixed rates on the same line, great. My experience is that one or the other will not be producing at the rated flow. the problem is a lot worse when the different types are rated for different PRESSURE as opposed to different flow rate. It also gets worse as you get closer to the capacity of the line (as LazyG suggests)

as to how long, I'm not sure my numbers will correlate, since I live in the second hottest place in the US, right after Death Valley. Phoenix is almost as hot, but not quite.
I run the garden 8 hours a day (at night) from May through September, or more accurately, when temps are 95+ day time high or more. In winter, I run every other day for 2 to 4 hours. and adjust for "evapotranspiration rate" in the months in between.
In my date garden I turn the drip on as soon as it hits 95+ and leave it on, never turn it off, until after harvest (usually Oct) and after the temps drop below 90. A mature date palm will take up 185 gallons of water a day on a 100 degree day, and we get a lot of them --smiles his jolly smile--. In winter I run 8 hours every 3 or 4 days. Again this is on very sandy soil in a very hot climate.

Pay the extra dollar or two for bags of pressure-compensated drip emitters and it's not a problem.

Yeah my total GPH for front and back on the one single zone is about 60GPH, that's probably why I haven't had any issues.

If you're still looking for drip solutions, I have found a perfect solution for my garden in adjustable drip emitters on a stake. See link below.
It's kind of a pain to try to drip every single plant, especially if you're trying to distribute water evenly to start seeds. I can water 4 or 5 plants at a time with each adjustable drip emitter. They adjust easily from 0-10 gph by just rotating the heads open or closed, and having them on stakes allows me to put the water exactly where I want it rather than wrestling with the ever-curling 1/4 tubing.
I buy the 25 packs of emitters at Home Depot for $17, and I can put 25 emitters (attatched to 1/4 tubing) on one 1/2 inch line with perfect pressure to all.
I water for 45 minutes every evening at 6pm. I have no solid data to back me up here, but my theory is that my plants are resting and restoring their strength in the evening and throughout the night and can best use the water then. I also think it ends the heat of the day a little faster for them. I also like to start my early mornings in my garden, so I walk around before it gets hot and wet the ground in an attempt to keep them cool for as long as possible. They seem to respond positively. Good luck!

Here is a link that might be useful: Dig Adjustable Drip Emitters

For those using drip hose, does it not clog terribly with the hard water here? It seems like a perfect solution except for that.

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thanks for the info everyone