Originally Posted by microfarmer

Make sure it is trash free! There is a difference between mulch and compost. Both can be used as a topdressing.

Mulch is not usually composted and is usually derived from tree trimmings, shredded bark, shredded trees, and other logging and lumber waste. Make sure you check for garbage mixed in, or that it is only tree trimmings if you are looking for 'mulch'.

Compost uses all types of yard waste and other industrial plant wastes (animal poop, grain hulls, spent mash from brewing, spent mushroom media, etc.) and 'could' also contain dried sewage sludge, mixed in, and then composted so it all breaks down. Compost needs to be fully broken down and heated to about 140-150 degrees (hot composting) before it is weed and pathogen free.

The problem with landfill greenwaste is that the curbside pickup cans get some trash from people who just don't care what can they throw garbage away in. It is near impossible to get landfill greenwaste without garbage mixed in. I work at a landfill as an equipment operator, and even though I 'could' prolly get some, I won't touch the stuff for that very reason.

Hope some of this helps.