Thank you for your voice and input, this is great communication and team work. Because of your interest, I went to work over the weekend to test and try additional solutions for doing away with weeds. Two important factors for any solution must be: no chemicals and without backache.
My goal: To collect enough data to conclude what works best on weeds and grass between bricks, along edges, or throughout a patio.
"Two important factors for any solution must be: no chemicals and without backache."
Mix 80 percent organic vinegar, 15 percent sea salt, 5 percent dishwashing liquid. You can try using a spray bottle to apply, but keep spray away from all other flowers and plants. (We poured our mixture onto the weeds and grass.)
The dishwashing liquid cut through the weed's protective coating, thus allowing the salty vinegar to be absorbed better.
Nature provided a scientific answer: Evaporation, Condensation, and wipe it dry so you don't have Precipitation back onto the weed. You can accomplish this by putting a clear plastic bowl upside down over the weed or building your own Weed Cooker like the one I made in the photo.
However, you need a hot cloudless day to kill tough weeds and crabgrass. They take four times longer to dry out than grass. By the end of the day you can do a whole patio with several bowls if the sun cooks them all afternoon long. The best part about a Weed Cooker, they have no smell and are reusable!
Bill Lauto, GTG