I laid down my cardboard and mulched over it. Got most of my cardboard from county public recycling bin at local firehouse .Got most of my mulch free. Then started buying the "broken bags" HALF price from big box store....
Seems like stuff did better than have the landscape fabric with mulch....
Just my chiming in....
jean

I lay it down and load on compost or wood chips ... Once it gets wet the worms start feeding on it.

I use it UNDER new beds, to smother, then I use it again to mulch but put straw over it. One thing I did learn was to use a single layer (so if you have extra thick cardboard, wet it and seperate it: I had extra heavy shipping boxes that were super thick) and to tear it into smaller pieces. The only time I ever use large sheets of the stuff is when I finish preparing a planting area that won't be planted for quite some time.

Depends on how fussy you are. I used to shovel dirt over it almost completely and/or add mulch on top. Now I'm dealing with health problems and don't have that energy. So I simply flatten it, lay it down between rows or plants and weigh it down with bricks or stones. After a good rain, it sort of just molds itself to the earth. No it doesn't get moldy, it just blends in. Water seeps right through it. If you want, you can give it a good soaking right after you lay it down or else just wait for rain. I have very few weeds in the garden. I overlap the peices by an inch or so and very few weeds are able to come up, and they are only around the edges where the cardboard ends.

We use cardboard boxes, flattened out, up at our community garden just to cover for the walkways as a weed suppressant. It ain't pretty but it works and it's natural.