With the exemption of a herbicide applicator's license you can use this homeowner product.
Preen!--Treats up to 800 sq.ft. if my memory serves me.
Comes in a yellow 5 lb. tub with a shake applicator built in to the container. Wear butyl rubber gloves and good mask before and while applying this stuff. The dust that comes off the stuff will make you cough.
Pre weed the beds and start with a clean bed and apply this material according to label directions, water it in with 0.5 inches of slow water or rainfall.
If you don't water it in within 3 days, you could have erratic results and weeds come back. The product tells you it will last up to 3 months but consider the temperatures and expect to reapply on 6-8 week intervals.
Lastly-----Read the entire label---their is an extensive list of plants you can spread it around.
One other thing---As I have learned in the knife selling business check with your parents before you go and purchase this stuff.