Keeping a garden mulched can cost a lot in terms of time and materials.
Organic mulches--bark, woodchips, shredded leaves, etc.--all decompose into their basic constituents, which are carbon dioxide and water.
That decomposition is good for the soil microbes--and the soil microbes are good for the plants--but for the gardener it means an unending chore of replacing mulch before you're left with bare soil exposed to the baking sun and opportunistic weed seeds. And for some, it means frequent dunning of the bank account if you buy mulch.
For our organic vegetable garden and our community garden in Burch Ave. neighborhood we scavenge old burlap sacks that once held coffee beans and use them to mulch the paths between beds.
It only takes a few minutes to spread several dozen bags to cover an area. I put them down with about 4" of overlap. After two or three months (depending on the season) a few of the toughest weeds (think nutsedge or bermuda grass) poke their heads through the weave of the bags. And a few annual weed seeds might germinate on top--like crabgrass in summer or chickweed in winter.
But here's the fun part. Before the weeds can get very big or numerous (I like to do this before there's more than a couple of weeds on each bag), I go back through the garden and flip every bag over.
Again, this only takes a few minutes and one of two bad things happen to the weeds:
1) The weed clings to the bag and its roots are ripped out of the ground. When I flip the bag the roots are exposed to the sun and the weed dies. This is usually the case with annual weeds that germinated on top and sent their roots down through the fabric of the bag.
2) If the weed slips through the bag and remains rooted in the ground, it still loses. When I lay the bag back down, it covers the weed and deprives it of light. A plant without light for 6-8 weeks will starve to death, since sunlight is food for plants.
(Ideally, any tough perennial weeds like bermuda grass have been eliminated before you start gardening, but their seeds can float in on the wind too.)
Counter Culture Coffee gives these bags away once they've dumped the beans into their roasters. You don't want to get coffee bags from any roaster--make sure they only use organic beans. One acquaintance picked up bags from her local coffee roaster and got home to find out the bags smelled like petroleum products. They probably had been sprayed with some nasty pesticide before being shipped to this country. She ended up tossing the whole lot.
As for the ink to make the lovely logos on some bags, I think they must be water-based. An artist who uses coffee bags for her work says the ink rarely survives a run through the washer. So I don't think they'll hurt soil life or contaminate any food plants.
Finally, because the burlap is also organic matter, after another 2 or 3 months the bags are deteriorating badly and need to be covered with another layer. But since they're free and take little time to spread, it's a small thing to put down a new layer twice a year.
And I can occasionally time my visits to the coffee roaster so I'm there for a free coffee tasting--or what they call a "coffee cupping" at 10 am on Fridays.
Now that's liberating.