my leech systems are fairly deep where my garden is as it runs back and forth down a slope.
UP at the top where my garden is It is over a foor down to the gravel. My is built where it has the leech drains,.. then about 6 or so inches of gravel on top of thay.. then a foot or so of dirt on top of that.
Since most garden plans root fairly shallow... I am guessing I shouldn't have a problem with roots getting into the lines.. but just to be safe... sounds like I should check the "average" depth for various plant roots, and anything that goes pretty deep.. just avoid planting them on top of the lines.??