Although we usually see smooth vistas of green grass growing in yards and parks, vegetated roofs provide an interesting location for growing grass. Vegetated roofs, also referred to as green roofs, provide an unusual, yet useful, site for planting and maintaining lawn grasses. This concept is nothing new. In fact, vegetated roofs graced many of the sod homes inhabited by America's early pioneers, as well as the original homes of the Native Americans and the Vikings. Grow grass on a vegetated roof to lower your heating and cooling costs with this insulating, living layer of green.
Construct your new roof, or remodel your old one, to meet the minimum load requirements for your vegetated roof. Check with your local building department to determine your municipality's requirements, codes and restrictions. Purchase any necessary permits before starting the construction phase of this project. To sustain grass on your vegetated roof, provide a pitch between 5 and 20 degrees to allow for proper water drainage.
Measure the square footage of your vegetated roof. Use a tape measure to determine the exact measurement of the green roof materials your structure requires. Purchase the necessary underlayment system from a green roof supplier. Most systems include layers of insulation, moisture barrier, waterproofing, drainage protection and filter fabric. Install your underlayment system in accordance with the manufacturer's instructions.
Lay your growing medium on top of your installed underlayment system. This layer of soil substitute comes in large squares for easy installation. Lightly water the growing medium with a fine spray, until slightly moist. Broadcast your grass seed across the top of the damp medium with a seed broadcaster. Make two or three light passes, instead of one heavy pass, to ensure even seed coverage.
Sprinkle your newly planted seeds with a fine spray of water. Keep the seeds slightly moist during germination and early establishment. Avoid overwatering the grass on your vegetated roof to minimize runoff from excess moisture.