Properly selected shade grass can grow well under oak trees with a little patience and extra lawn maintenance. The fine-leaved fescue grasses are recommended by the University of Rhode Island for planting under trees. There is no need to give up the notion of having grass under your oak trees. The key is to learn a few growing tips to successfully get grass in this area of the yard.
Prune away any branches that are lower than 8 to 10 feet from the soil line. Removing these branches increases light to the grass, advises the University of Rhode Island.
Examine the oak tree and prune away smaller branches, particularly ones inside the tree canopy. Thinning the tree does not change its general appearance and reduces shading from the canopy.
Place an appropriate number of tree fertilizer stakes into the ground at regular intervals. Additional nutrients for the tree reduces soil nutrient competition with the grass.
Adjust lawn mower blades to their highest setting. Shade grasses should remain between 2.5 to 3.5 inches, recommends the University of Rhode Island.
Fertilize the shade grass with a low-nitrogen lawn fertilizer, instead of the traditional lawn fertilizers used on non-shady grass.
Reduce watering the grass to once a week or bi-weekly. Too much moisture increases the chances of powdery mildew and other diseases, warns the University of Rhode Island.
Dig a 2-inch deep narrow trench just beyond the oak tree's drip line to provide irrigation to the tree while preventing a rise in moisture levels in the grassy area under the tree.