I was on a farm visit this last week and ran across this drip irrigation line being utilized on the ranch. Of course I am a drip irrigation enthusiast. The system shown in the photograph was attached to a ½ black poly line. A ¼ inch line was attached. This ¼ inch line had a drip emitter spaced every 12 inches preinstalled in the line. In addition, it had small valve was installed in the line so that each individual drip line could be turned off or on without disrupting the flow to the other drip lines. This 12 inch spacing is ideal for most of our heavy soils. If your garden is in sandy soils you may want seek out a drip line with emitters spaced every 6 inches.
Drip irrigation has several advantages. As you can see from the picture the ability to place water exactly where you desire it is a huge advantage. No evaporation loss. Less strain on a home water system are just a few of the advantages. Cost was one of the disadvantages several years ago but prices have come down making drip irrigation it a valuable addition to the home garden. The water savings alone will likely pay for your system.