Sandy took out two beautiful 60-foot maple trees in our back yard. With one of them we had the stump ground, so its now a heap of mulch. I would like to plant a new tree in the same location. What do I need to do to prepare the spot where the stump has been ground. Should I incorporate the grindings, or remove them and replace with top soil?
My county/parish agent told me to set the shavings aside for one year before using. I put them in old plastic garbage cans. They take too much of the nitrogen out of the soil and should not be used immediately after cutting.
Remove most of the sawdust from the grinding. No need to be fanatical about it, though.
If you have extra soil anywhere in your yard it is better to use the same soil rather than bringing in something different.
If you have to import soil then try to find something that is as similar as possible to the soil that is there, and blend it with the surrounding soil. There should be a gradual transition from existing to imported soil.
Make sure you add some fertilizer that contains nitrogen (first number on the label) to make up for the nitrogen the remaining sawdust will need as it decomposes.
If you end up with a mix that includes up to 25% sawdust it should be OK.
Make a bit of a mound. As the sawdust decomposes it will sink, and the fluffing that happens when you import and blend the new soil will settle, too. You do not want the new tree to end up in a low spot.
Monitor the new tree and stay on top of its fertilizer needs, since some of the fertilizer is going to support the decomposer organisms that are so thoughtfully working on the sawdust for you.
To compost the sawdust the fastest add nitrogen and keep the sawdust in a pile. You can contain the pile with some material that breathes, plastic garbage cans are not very good. Turn the pile occasionally so oxygen gets into it and it stays about as damp as a well wrung out sponge. Good nitrogen sources include lawn clippings or fertilizer.