There are a few different options to consider when ridding your lawn or garden of an old tree stump, each with its own set of pros and cons:
The cost isn’t typically prohibitive, and if you agree to clean up the grindings and replace the soil yourself, you may be able to save a little on the price. The cost is approximately $5.50 an inch diameter and is charged by the widest points on the stump. A smaller stump might be around $50 whereas a 12” diameter stump can cost around $75. The grinding hole will be larger than the actual stump in order to remove the buttressing roots and is usually ground to a depth of 12 to 14 inches.
Some important things to remember:
This usually involves digging around the stump and using various methods (ax, chainsaw, chain and vehicle) to remove the bulk of the stump out of the ground. This method can have several drawbacks: soil around the cutting surface can ruin a chainsaw blade, the chain and vehicle method can be hard on engines, all of the above can lead to back injuries. Unless you are planning on utilizing the exact site for another planting, there is no reason the stump cannot be left in the ground after grinding off the top or letting rot naturally.
There are a few products available to help decay tree stumps, however their use must be exercised with extreme caution or avoided altogether. It is now understood that tree roots spread much wider than previously thought and that they often graft with roots of other trees, particularly if they are in the same family. Therefore, chemicals applied to a live tree stump have the potential to spread to other nearby trees and cause injury. Trenching around an undesired tree stump, to a depth of 18 to 24 inches, will assure that any chemicals applied to the stump will not effect other nearby trees. However, depending on the proximity of the other trees, the trenching itself may cause damage. When other desirable trees are nearby, stump grinding or allowing the stump to rot naturally really are the best options.
For some additional information, this website gives a few good tips: http://www.ext.colostate.edu/ptlk/1740.html
Finally, note that there will be some settling over the next few years and you may need to add soil again to level the site.