So far only one good rainstorm has graced our garden this year, followed by six weeks of sunshine.  The weeds have taken off and been mowed down a few times.  We were happy to have the weeds germinate, to form a good holding root system to prevent erosion, but that's about their only desirable trait for now.  The mulching committee, headed up by Nancy H., have started incorporating different types of mulching and weed control for demonstration purposes.  Our biggest project have been to suppress the weeds around the inner perimeter of the garden. 
Sheet Mulching is a great way to convert a weedy area into a garden or to convert a lawn into a mulched landscape.  The first layer that we used was 2-3 inches of beautiful compost from Cold Canyon Landfill that is made from all plant material.  The second layer was a layer of green compost, composed of shredded phone books and composted horse manure, watered once, followed by a single layer of cardboard and lastly covered with about 3 inches of wood chip mulch.
Sheet mulching works to suppress weed seed germination, by blocking the light.  The cardboard usually decomposes in one year, leaving a rich, healthy soil, that will hold more water and nutrients and will be ready for planting.  You can also put plants in before hand and do sheet mulching around them, just be careful not to get to much  mulch around the crown of your plants!  We have tried different variations, depending on availability of supplies, some of our areas were missing the green  compost and some areas replaced cardboard with thick layers of newspaper.
We started a trial of different weed controls on the South end of the garden, for a side by side comparison.
Yikes!  We have grass growing up through the decomposed granite pathways!  We used a propane torch to kill the grass.  It doesn't have to burn all of the way, just enough so that the grass get's a dark green color and leave the impression of a finger print when squeezed.  It starts looking like the color of cooked asparagus!  Always follow with a hose, just to make sure that there's no burning embers.  Make sure to use a water breaker to soften the flow, because a heavy stream will leave unsightly damage to the  top layer of the decomposed granite.  The picture above is from November 24th, healthy weeds.

Here is the same grass the next day after burning (November 25th)

Here's what it looks like on November 30.  Still some weeds persist.. but much better.

Bindweed!  You may have spotted it growing in the freshly plowed vegetable fields on the central coast, with it's beautiful morning glory flowers.  But don't be fooled!  This weed is so persistent and aggressive, that there's little control over it!  We have a couple spots flagged throughout the garden.  Even though the patches are small (approximately 2 feet wide) we are attempting to control them before they take over.  We have 2 different herbicides, 57% Pelargonic acid, used at the 3% rate, and Glyphosate.  We are documenting the affect of them.  The Pelargonic acid is fast acting, because the acid burns the foliage and there is a noticeable change within days.  Glyphosate may take up to two weeks to show damage.

Before herbicide applications.

(Image Above)Pelargonic acid damage on grass and bindweed.  5 days after application.

(Image Above)  Glyphosate 5 days after application.  If you look hard, you can see that the bindweed still looks healthy!

As you may be able to tell, we have a thick layer of grass growing into the edges of the DG Pathways.  We did one application of (3% Rate)  of Pelargonic acid.  In 5 days, we had dramatic results! (see below)  We did use the weakest rate on the label, which is recommended for soft, new growth.  Since this grass is several weeks old, we may need to increase the rate.  Remember to ALWAYS read the label for rates! 
There is also a benefit to having the grass germinate close to the edge of the paths.  The roots actually act as a stabilizer on the edge of the pathway!  Even though the foliage is now dying, the roots will stay intact and keep supporting the edge of the path!

There's not an easy answer and a lot of work when it comes to weeds!  Hopefully, your garden is already covered with a good layer of mulch and just a quick check with a hoe before they get large will be all that you need!

For More Information on Sheet Mulching by Washington State University Cooperative Extension, please see the attachment below. (click on the underlined title)