Although spruce trees enhance the landscape and provide an opportunity for birds to nest, they prohibit lawn grass from growing underneath, creating patches of bare soil. Not only does a spruce tree drop thick mats of acidic needles that impede grass from growing, but the dense foliage prevents sunlight from filtering through and reaching the ground below. With proper grass selection and care, you can grow a thick carpet of grass right under your spruce trees.
Wear gloves and rake the area under the spruce tree to remove fallen needles, rocks, stones and debris, exposing the soil. Collect in a wheelbarrow and dispose.
Snip off low-lying branches to a height of up to 2 feet. Use sharp pruning shears and make straight cuts instead of jagged ones. This allows sunlight and air to filter through to the bare ground below.
Loosen the soil with a hand shovel and remove up to 2 inches. Work carefully and slowly so you do not damage any roots. This layer of soil contains acid from fallen mats of needles that prevent the growth of grass.
Add fistfuls of fresh topsoil over the area and rake deep so it mixes with the existing soil. Water the area with a garden hose until evenly moist.
Spread seeds by hand, or use a seed spreader for an even distribution. Select shade-tolerant grass seed that withstands acidic soils such as Creeping red fescue or Kentucky bluegrass if you live in the north, or St. Augustine for the south.
Rake the seeds to ensure they go ¼ inch into the soil. Spread a thin layer of lawn lime over the seeds to increase the pH level and make the environment conducive for germination.
Spread a ½-inch-thick layer of mulch, peat moss or compost over the seeds to prevent birds from picking them. Mulching also retains moisture and adds essential nutrients to the soil.