All about rooftop gardens
Years ago, having a green roof usually meant there was moss growing on the north side – and a problem with worn-out shingles and moisture for the homeowner to tackle. Today, we are actually “planting” green roofs, with sustainable ecological benefits.
Lori Davey is Administration & Design Assoc. at Sedum Master Inc., a Princeton, Ontario supplier of green roof plant material. In this HOSS Q & A, we discuss “growth opportunities” for eager DIYers. What you learn may surprise you!
Green roofs are attracting a lot of interest, but is this really a DIY project?
For a small green roof project, all it takes is the right products and a bit of sweat, muscle and dirt (as we say growing medium) to create your own beautiful “living” rooftop. More DIY customers are using our special sedum mats every year. (Sedums are a hardy, succulent plant that come in hundreds of varieties.) These pre-cultivated mats can be easily cut into different shapes and angles with a sharp knife, and people love the wide variety of plants that comes in one product. For larger green roof projects, though, we recommend hiring an experienced green roof installer.
Can I put a green roof on my dog house?
Absolutely! Be creative. Our customers have done everything from garages, saunas, pool houses, birdhouses, dog houses, sheds/garages, outhouses, treehouses, gazebos, to using the green roof mats for lawn replacement, septic beds, flower beds, wedding décor… you name it.
Cost-wise, what are we looking at?
Our regular Sedum Mat ranges between $3.50-$4.00/sq. ft. and weighs approx. 8 lbs. per sq. ft., fully saturated. We also have a lightweight FeatherMat, which costs from $4.00-$4.75/sq. ft.; approx. weight 3 lbs. per sq. ft., fully saturated. This mat is ideal for rooftops that have a weight restriction. Both mats come in one square metre and two square metre sizes.
We also have 10 in. x 20 in. and 15 in. x 20 in. Sedum MiniMat options that are perfect for small DIY projects.
Is maintenance an issue?
The bigger the green roof project, the more intense the maintenance. Customers need to realize that these are plants and, just like you maintain your flower beds, you should maintain your green roof, as well. For larger green roofs, an irrigation system needs to be put in place, and we highly suggest a maintenance plan for care and weeding.
For smaller roofs, or DIY arts & crafts projects, water the sedums a few times a week until roots take hold. Once established, water as needed. Make sure to weed and clean debris. And if you like talking to your plants, go for it!
How long will a green roof last?
Depends on how you maintain your plants; if you don’t care for them, things can happen. For the most part, sedums are very tough and aggressive. They store water in their fleshy leaves to sustain during drought seasons, while grass and other plant life seems to wither away. There are hundreds of sedum varieties; some flower in early spring, others in summer or fall. The blooms are striking, en masse, in shades of white, golden yellow, pink and red. The zone you live in is key to choosing which types will work best.
Are harsh winters and heavy snow load a concern?
I’ll put it this way, our green roof products are laying in the fields all through a Canadian winter and they perk up lush and colourful every spring! Some sedums actually take on a brighter, more intense shade of burgundy through the winter months. Just be cautious of shoveling snow off of them, as you may dig them out and damage the plant.
Thinking of greening up the garden shed this weekend? Easy breezy!
- Make sure roof is structurally sound to withstand the weight
- Clean roof of debris
- Lay down a waterproofing membrane (ex. 45ml plastic or a pond liner)
- Lay down Sedum Master’s empty panels (1m2 drainage board with water retention mat)
- Interlock all panels together
- Rake out a suggested 3-4” of growing medium overtop empty panels
- Roll out the pre-planted sedum blanket
- Give it a drink of water
Retro-fitting a house or building with a green roof has many benefits. Not only does the vegetation act as a natural filter for air particulates and rainwater, it adds insulation to the existing roof – reducing heating and cooling costs. Always consult a structural engineer and/or architect when considering a large project green roof.