Experts and BHG readers answer.
I hate crabgrass
The way to treat for crabgrass is preventively. Now that it is growing up in your beds, do the best you can pulling it, but accept that it will be with you until frost, which kills crabgrass. Next spring, in March, put down a product called corn gluten. It's an organic control that prevents crabgrass from growing. NOte that corn gluten will prevent other seeds from germinating as well, so don't apply it and then plant flower seeds. YOu'll want to repeat the treatment one or two times more (read the product label for retreatment intervals). Also, a good, thick mulch will do wonders.