Concrete is no friend to grass, and growing grass on top of concrete has led to something of a debate among gardeners. If removing concrete is not an option, growing grass on concrete is feasible as long as there is proper drainage and enough topsoil. Successfully growing grass over concrete will lead to the concrete breaking down over time. It may take years, but it will happen. Simply make sure you have enough soil, fertiliser and seed---and upkeep of the area is an absolute must.
Inspect the area you wish to grow grass on for any loose concrete. Make sure there is a way for water to properly drain from the area. Rake loose concrete and dispose of it before putting down topsoil.
Apply topsoil to concrete area. Place at least 4 inches of topsoil over the concrete. Measure topsoil with a ruler or measuring stick to make sure you have the right amount.
Sprinkle fertiliser over the topsoil. Use either fertiliser from your local garden supply centre or compost from your own compost pile. Mix well with topsoil. Follow with an application of grass seed. Grass seed known as "creeping red fescue" is considered one of the best grasses to grow on concrete as it can grow just about anywhere. You may also want to mix it with other types of grass seeds.
Maintain this area for a beautiful lawn.
There are numerous grass seeds that claim to be the hardiest and will grow on any surface and plenty of online resources on such matters. Simply do the research and find out which grass seed will work best for you.
Attempting to grow grass on concrete in an area without proper drainage can kill the grass you are trying to grow. If drainage is an issue, you may want to consider breaking up the concrete before putting down any topsoil.