I thought that disturbing the soil in any way, including pulling weeds from it, increased the chances of more dormant weed seeds being brought up to the surface.
That's the philosophy behind the chemical control, no-till methods our county extensions recommend. Compost, poison, then mulch.
I had an area that didn't get mulched and the plants in that area seemed to do fine in the heat this summer. I wonder if the lack of mulch caused the plants to send roots deeper? The ones I keep on the dry side on the summer do better in winter stress.
