Irrigating square foot garden 4x8 12" deep

How can I irrigate the garden most efficiently while using cover crops like cardboard and newspaper. I have (3) 4x8 raised beds 12" deep. I spent hours looking but I'll I found is 1/4" with dripline emitters every 6" running the length of the bed with rows spaced 6" apart. One person said that the 1/4" tubes were hard to keep in place and suggested running (3) 1/2" distribution line with flag emitters every 6". She then went on to say it wasn't working to well. Has anyone had experience with this? Thanks for comments..Love this site!!!!

I use landscape pins to keep my 1/4" dripline in place.

I bought staked emitters from dripworks. I ran a 1/2" line along the long axis of each bed, with a 1/4" line going along the short axis every 12". On these short lines, I have a 2 gal/hr emitter every 12", for a total of 3 emitters. From everything that I've read, a drip emitter will provide water to a 12" diameter area(6" radius), so I'd assume that would also mean 6" down too. To get the full 12" depth, you'd have to run longer or water more frequently(but not necessarily double). Add an extra 50% of time running per watering and then check to see how it does.

unmutual, I have a similar set currently with 3 1/4" emitters the length of the box spaced a foot apart; however it is preset at 1/2 gph. Is this enough, or do I need more drip lines? thanks

The Short Answer: No, you just need to figure out how long you have to run the irrigation system.

The Long Answer: From what I understand, a plant needs 1" of rain per week, which is the equivalent of 0.56 gallons. If you ran your irrigation system for an hour per week(best time is 4am) that would give your plants almost enough water under normal circumstances. However, when it starts getting hotter, you need to water more(for my area it can be very frequently, like every other day if there's no rain). Since you live in Oregon, I'd suggest investing in a rain gauge, since you have plenty of rain to begin with, so you can find out if you even need to run the irrigation that week. There is nothing better than rain water for plants.

To test the moisture level, stick your finger into the MM. The closer the moisture is to the top, the less you need to water, and water always travels down(having a dry spot at the bottom would be strange, but maybe if you have TT SFGs, it might be a problem, I don't know). During periods of high temps(80+), you might never be able to keep the top inch or so moist for any length of time(I'm already having problems keeping the top inch moist).

You can buy all the fancy meters you want, schedule your irrigation system in convoluted rhythms, but nothing beats sticking your finger into the MM to check. People use mulch on their SFGs also, as this retains moisture by reducing evaporation(one thing I vow to do sooner or later...).