This is not to say that with the above four steps — drip irrigation, mulching, keeping traffic off planted areas, and not tilling — weeds never appear. They do. But weed problems do not.
What few large weeds do appear get yanked out of the soil, roots and all, coaxed out, if necessary, with a garden knife or trowel at their roots.
Colonies of small weeds are quickly done in with a "winged weeder," colinear hoe or some other hoe with a sharp blade that can be slid along parallel to and just a fraction of an inch below the soil surface.
Also important in keeping a garden weed-free is to search regularly for them. With the above four steps, this activity is pared down to nothing more than a few pleasant minutes per week.
Lee Reich is the author of "Weedless Gardening" (Workman, 2001)