Many winter annual weeds have already come up: cheatgrass, alyssum, field pennycress, and more. The key to controlling winter annual (and summer annual weeds a little bit later) is to control them before they go to seed. The trick is to get all of the seeds that germinate, and to not let any go to seed. New crops may come up from the seeds that are in the soil; get them while they're little, too. A few years of persistence, and you will find dramatically fewer weeds. But persistence is the key!
In a perfect world, you'd just hoe them all under when they look like this:
|Field pennycress (Thlaspi arvense) just germinating -- so easy to hoe at this stage|
|Cheatgrass (Bromus tectorum) before flowering. Just hoe - no need to bag.|
This is the ideal stage to control these annuals, because there are no flowers and thus no seeds, so no need to pull and bag seed heads -- a tiresome and land-fill intensive process. Also, the root system is small and fragile. It is very satisfying to go out and destroy thousands of weeds with a few whacks of the hoe. Sort of like the fairy tale of "the Valiant Little Tailor" who kills seven with one blow. This is also a good time to use an herbicide, if that's what you prefer.
Depending on where you live and the weed, it may or may not have gone to seed already (sorry I didn't get this posted sooner!).
|Cheatgrass gone to seed|