What non chemical product can I put on a stump to make it decompose?

I believe you can use baking soda. Bore out some of the top and dump it in. Takes a while.

Drill in lots of quarter-sized holes about 8” down, and fill with epsom salt. Add a bit of water. Repeat the salt as necessary.

It will take time, so please be patient

We decided to build a flower garden on top of ours. We wet down th stump, put dirt on top, covered it with landscape cloth (this will allow water to keep getting into the stump) and covered with mulch and straw...set out flowers in pots.

They wanted $400 to grind stumps!!

Here is a link on getting rid of a stump naturally.

http://www.treeremoval.com/stump-removal/how-to-burn-and-rot-tree-stumps/#.W0ikI9VKgnQ