Question: I have low spots in my yard and I’d like to raise its grade. How will that impact my lawn and shade trees?

Answer: Be really careful. You can actually take several inches of soil off the top of a tree’s root system and do less damage than if you added the same amount. The majority of any tree’s roots will be in the top foot of the soil, so adding soil risks oxygen depletion in the root zone. If you have to do significant grade changing, build a retaining wall and a well at the original grade. An arborist can consult with you to determine the size of the well for the specific tree and location. As a practical measure, however, you could add soil to one portion of the tree’s root zone, so long as you don’t cover more than 20 to 25 percent of the roots. As for the lawn, fill shallow low spots with washed brick sand. Use dry sand so it can filter down through the runners, and try not to use more than 1 inch of sand. If the low spots are deeper, dig the sod and put new topsoil in place before you replant the grass. April and May are ideal times to accomplish these changes.