There is a nifty product on the garden department shelves to help you get off your knees and enjoy your summer a little more, its call Preen.
Preen is a pre-emergent weed seed killer; which means poison enters the weed seed and snuffs it out just after its little shell cracks and the seedling starts to grow. It will not kill anything in your garden that is already growing; you’re back on your knees pulling those, or, the up side, standing there admiring what you’ve planted. You can also buy this with a fertilizer add to it.
Its lasting ability will give your flowers more than enough time to bush up and choke out the sunlight to any would-be spoiler seeds that may have blown in after its effectiveness has worn off. Your weeding then has been reduced to just flower perimeter weeds.
I would not use this or any chemical pesticide in the vegetable garden, keep that area as chemical free as possible; let just the veggies enter your mouth. A bug that has used your broccoli head as a McDonalds, and possibly a highway rest stop, will never mess up your DNA chain or cause your gene pool to stagnate.