It sounds like you want to grow vegetables and flowers but are unable to pull weeds. The weed and feed product you may be thinking of is made for lawns as it kills all broad leaf "weeds" and that would include lettuce and most vegetables and flowering plants. I do not know of any product you can sprinkle on the soil to kill weeds but still grow edibles and plant seeds of flowers. My best advice is to lay down sheets of newspaper and put the mulch on top at least 3 inches deep. Then make a slit into the paper and mulch to add your seeds and young plants. This way the paper and mulch will block the weeds but seeds can still sprout in the openings in the paper. A long handled hoe is another tool you can use to uproot weeds without bending or getting down on your knees. Hope this helps you to keep on gardening and Keep Growing, Marianne Binetti