Hi Rory,

Are you willing to cut out a narrow section of concrete walk at the spigot and tunnel under the footing of the wall, then pour back the cutout section of the walk to make a permanent spigot on the other side of the wall in the garden area? If not then drill a hole at the bottom of the wall and run hose through the wall hole across your sidewalk and make an additional spigot location in your garden area and attach it permanently to the garden-side wall. Then purchase a battery operated controller with vacuum breaker for the new spigot end and attach your drip system to the new controller/VB valve and good to go. It will be a fully automated system. HTH GL.

That's one option, but there are others. There are permanent solutions that involve you digging and getting dirty, muddy and probably wet. You also might not have to cut concrete, but you would have to fashion a jet lance with a 12 or 14' long piece of 1/2" piece of copper or galvanized pipe and a garden hose.

However, the easiest solution, which I think is what your are asking for, is to buy a book or two on drip irritation systems from ebay, Half-Price Books, Lowes or Home Depot. I bought two off of ebay and one from Half-price Books. The one I bought from Half-price books is by Ortho and is the one I used to put in a drip system around my house. It's a simple book and easy to read, follow and understand. There's one available on ebay right now as I type.

http://cgi.ebay.com/SPRINKLER-DRIP-IRRIGATION-WATER-GARDENING-ORTHO-2006_W0QQitemZ360048777945QQcmdZViewItem?_trksid=p3286.m20.l1116

It would be fairly simple once you figured out the types of drip heads or drip emmitters you needed to run the drip pipe. I dug a small, shallow trench for my 1/2" supply line and an even shallower trench for the 1/4" line from the supply line to each plant, or you could simply bury the lines under mulch.

There is a female hose connector that attaches to the 1/2" supply line, and you just screw your male hose in into it and turn the water on. However, your garden hose would be laid across the concrete, but you would only need to unroll enough hose to go up the retaining wall and connect to the 1/2" main drip line, that you might want to place at the top of the retaining wall close to the edge.

Right now our local Walmarts have their drip irrigation kits on sale. The kits include everything you need to set up a drip irrigation system, but no timer. You'd have to buy the timer separate. There is a manual time for about $10, and a battery powered one for about $20. These packages are cheap and probably not what you would find in a professional landscaping supply store, but they are easy to install and I haven't had a problem yet.

Walmart has 3 kits: one is for a small container garden, one is for a small regular garden, and a larger kit is for a medium sized yard. These kits include the filter, pressure reducer, connectors, dripline (1/2" and 1/4")and emmitters.

GOOD LUCK!!

I set up a similar system a couple years ago. I run 200 feet of garden hose, then connect it into 1/2 inch poly pipe which has 1/2 gph emitters in it to water some very small bushes. You can find the correct ends in the same area as the emitters and black poly in the store. Due to the low volume of the emitters, I turn the system on at night, then turn it off the next morning on a weekly basis. Will be moving to higher volume emitters and eventually getting ditchwater to the bushes.