October is a perfect time to take care of those pests since we are out there doing seasonal maintenance. Actually, anytime is a good time to avoid the over-population of the pesky weeds.
The secret is to not let the weeds set seed. Pull them out or kill them before they have a chance to seed.
Anytime I am walking around the garden, I make sure to go out with a plastic grocery bag and pull weeds here and there as I encounter them. It is so much easier to keep them under control if you routinely pull them out as you are just wandering around.
Want to identify the weeds that grow on your property? What Weed Is It is an excellent article for starters. It includes links to other articles and publications.
Weed Management Guide for Florida Lawns is another resource for Florida gardeners as well as gardeners in all zones since it includes some great information about weeds in general.