A roof is a very different environment from a garden at ground level. You’ll probably want to get professional help before getting started on a project like this.

Benefits of building a rooftop garden:

Container plants need much more frequent watering than plants in the ground. By midsummer, if not earlier, you would need to hand-water at least once a day and in very hot weather, twice a day.

That schedule is nearly impossible to maintain every day all season, which is why a drip system is crucial.

Consider the climate on a roof, which is more severe than on the ground. If nearby buildings are tall, the garden can be in shade all day, which is too dark for many plants, or quickly switch from deep shade to intense sun.

Reduce stormwater runoff
Reduce your air-conditioning costs
Reduce your heating costs
Create habitat for bees, birds and butterflies
Provide outdoor space for you to enjoy
Beautify the built environment
Improve air quality
Allow you to grow food
Earn LEED credits
What makes designing roof gardens different?

Once you get approval, consider hiring a qualified garden designer who specializes in roof gardens, especially if you have limited gardening experience.

Container plants need much more frequent watering than plants in the ground. By midsummer, if not earlier, you would need to hand-water at least once a day and in very hot weather, twice a day.

It is essential that you get approval from your landlord or building co-op board and the local planning commission.

They will probably require that your roof be examined and certified by an engineer or architect, who will stipulate required changes to the surface of the weight and the roof limits for your plants, containers and structures.

Consider the climate on a roof, which is more severe than on the ground. It’s often quite windy in summer and hot and very sunny. If nearby buildings are tall, the garden can be in shade all day, which is too dark for many plants, or quickly switch from deep shade to intense sun.

Plan on building some wooden or lattice screens on the windward side of your plants to keep them from developing a permanent lean. Lattice can also provide some shade, especially for a western or southern exposure.

Never use regular garden soil for a roof garden; it’s much too heavy and doesn’t hold water well or offers poor drainage. Use a lightweight artificial soil often called a “soilless mix” in your containers.