Baking soda neutralizes the ph in the soil and nothing will grow there. use baking soda around all of the edges of flower beds to keep the grass and weeds from growing into beds. Just sprinkle it onto the soil so that it covers it lightly. Do this twice a year - spring and fall.
Natural Weed Killer - Martha Stewart Eco-friendly choices ... Warm weather can coax weeds to pop up from the tiniest cracks in the sidewalk. But don't go for the weed killer. Douse them with vinegar, lemon juice, or boiling water instead. The weeds will likely shrivel in a day or so; resilient ones rarely withstand a second treatment.