Jackson County Office:
http://extension.missouri.edu/...
Master Gardeners of Greater Kansas City:
http://extension.missouri.edu/...
If you're not afraid of biosolids (digested sewage sludge, tested for microbes and heavy metals), try Googling local sewage treatment plants, or city departments related to solid waste treatment. Often you can take away as many biosolids for free as you can shovel into your truck.
Or they give away all the biosolids to a company that has the municipal composting contract, that takes wood chippings and yard waste and sawdust paper and biosolids and compost them. Some cities give that garden-ready compost away.
Some (like Cedar Grove) get their raw materials for free, and then sell the product in bags or by the cubic yard. I look for "dirt yards" and always remember to ask what the delivery fees are. You might look up the distance from the dirt yard to your yard, so when they tell you the delivery fee, you can faint and THEN say "but it's only XYZ miles!"
