Hi, I totally agree with Timothy Norton. Very thick mulch is, for me, the way to go.
I'm busy converting the corner of a paddock into a garden, and nothing comes up through 30cm wood chip mulch. This is the second time I've used this method, the great thing is that after year or so you can scrape it back and plant through it. I scrape back a small bucket size fill it with soil/compost mix, plant my brocolli or whatever and put the mulch back, close up to the plant.
Check out Paul Gautschi, Back to Eden gardening.
Good luck! By the way I'm 70, 5'0" and mulching/ no dig makes my 1/4 acre garden very manageable.