>> raised beds on legs
Another way to keep veggie roots out of leach fields is to lay down heavy plastic or other long-lasting root barriers before you collect soil and compost to lay on top.
Just plan for drainage if you lay plastic under your raised beds! It sounds as if you have some slope or grade to work with, so arrange the hard soil under your raised bed to slope down towards some slope or grade that will carry your bed's drainage to a part of the yard that won't puddle or flood.
Of course, a "plastic floor" under your raised bed prevents the root zone from growing deeper as the unimproved soil absorbs organics from the bed itself. But I have heard people online panic about roots (even vegetable roots) getting into drain lines. I don't believe everything I read online, but I also don't know enough to dismiss their concerns.
In the yard where I grew up, the ONLY place that the grass was green was right over the drain line. Green and lush there, brown all summer elsewhere. I always thought that would be a great place to put a garden! Deeply irrigated PLUS deep-fed with organic fertilizer.
If you don't have a dry season dry enough to show clearly where your leach field is, all I can think of is to ask the contractor who worked on it to give you a quote for finding out. When I was looking at real estate in NJ, proof of an adequate septic system was a very big deal, and anyone hoping to sell a house knew they had to have proof of meeting local codes and recent inspections.
Maybe a local realtor can tell you where to look for the original septic system plans that I assume must have been filed somewhere. The realtor who SOLD you the lot might not be the best one to ask, if they are like NJ realtors.
Once we asked two NJ realtors whether something they suggested was ethical. Their answer was "yes, it's legal". We couldn't make clear the concept of 'ethical" clear to them, but apparently they looked it up and discussed it after we left. The next day, they used the word "ethical" several times, boastfully, proud of having learned a new word even if it wasn't relevant to their usual daily business.
>> buy a couple hundred-foot hoses and string them together,
It might be cheaper or longer-lasting to buy a roll of 1/2" or 3/4" black polyethylene irrigation "mainline". You can leave that pressurized 24/7 if you want. I found a better price for 3/4" tubing at a local store (Steuber's Distributing) but you can buy irrigation tubing and connectors from places like Dripworks or even Home Depot.
1/2" - $14 / 100 feet 240 GPH = 4 GPM
3/4" - $31 / 100 feet 480 GPH = 8 GPM
I think it lasts forever if you don't puncture it, let it freeze solid, or expose it to harsh UV (that is, bury it or cover it with mulch). Once you lay the mainli8ne out into your backyard, you can add as many spigots as you want for just $3-5 each. Plus stick sprayers, spinners or dripline into the mainline and water from timers.
http://garden.org/ideas/view/R...
