Controlling Crabgrass starts with understanding something about how it grows. One simple means of control is to mow your grass at the highest setting your mower will allow since that longer grass will shade the soil where the Crabgrass seeds are laying, waiting to germinate. If the soil temperature is kept cool those seeds will not germinate.

Here is a link that might be useful: About Crabgrass

Thank you for responding to my post. I did not specifically intend to just prevent Crabgrass. Want I was thinking of is using crabgrass preventer to prevent all other weeds from germinating. I believe that is what I think the crabgrass preventer does is keep the seeds from germinating. So I thought maybe that could be used instead of a product such as Preen in my flower and vegetable gardens. This would be a lot cheaper if this would work.

Crabgrass is a grass. Most of the other weeds are what are called broad leaf plants. Generally but not always a grass killer will kill grass but not broad leaf plants.

Look at the package to see what it does kill. Do not use in your vegetable garden. Use your hands to pull plants or mulch heavily. Anything you eat can pick up the chemicals you apply.