I'm a gardener, biology major, chemistry minor, and a certified Frog Watch USA volunteer, DO NOT USE CHEMICALS ON YOUR GARDEN!!! I know it's a pain in the neck, but please just pull them out by hand. Not only do you risk getting your pets and yourself sick from eating food that might have grown with some herbicide on them, but you saturate the soil with it which will spread into the ecosystem and hurt everything from beneficial bacteria to endangered but critical plants and animals like bees, birds, and amphibians. Besides, you'll likely have the soil continually killing off your good plants if you plant them in the dirt with the herbicides.
If you don't want to pull them out by hand because it's boring, what I usually do is I just listen to The Office or some other TV show on my phone and get pulling. You'll have significantly healthier dirt and plants if you keep your garden organic and free of any weeds. You'd be surprised how easy it is to remove weeds if you use some handheld tools. Also just weeding once or twice a week will cut down significantly on the amount of work you'll have to do out there. Just please promise me you'll never ever use herbicides again, those are so horrible for our ecosystem.