How to Plant a Roof Garden

Consult with a building contractor before you begin building your garden. Ensure the roof is strong enough to hold the extra weight of soil, water and plants and that the roof material is in good shape and won't leak. Make any necessary amendments that the contractor recommends.

Set up containers for the plants along the edges of the roof. The edges have the strongest support because they are over reinforced beams. Place smaller container plants like herbs in a more central location. Choose containers that are large enough for the plants and have good drainage holes in the bottom. Light-weight containers like those made from plastic are easier to get onto the roof.

Choose roof plants carefully. Plants that tolerate plenty of sun and warmth are necessary. They also need to grow well in containers. Tomatoes, peppers, onions and carrots work well. Plants that need a lot of space can also work if they are grown in the right containers. Potatoes grow in barrels and small, bush squash varieties work in large containers.

Set up a system to collect rain water. Several barrels or small troughs around the roof work to catch water for you and will lighten the water load. It's easier to have water on the roof already than to haul it up.

Plant the garden according to the needs of each individual plant. Water seeds thoroughly and keep them moist during germination. It is important to keep roof plants moist because the roof gets so hot.