Easy Way to Grow a Flower Roof or Wall Garden

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Ideas for Green Roofs

This is a simple way to add a living roof to any small structure in your garden that has a sloped roof. Unlike a permanent green roof, this style is lighter-weight, perfect for annuals, and can be removed at any time.

Backstory

I built my mini greenhouse a few years ago after finding a bunch of free, old house windows at the side of the road. I initially used windows for the roof but, after a few years of wear and tear, I found that they were not holding up to the weather despite many protective layers of exterior paint and sealant because there were too many nooks and crannies catching rain water and debris from the trees. I then decided to try and find some old tin tiles to use as roofing but, after searching for a few years, I haven’t been able to find any for a song. Sure, money can buy anything, but I want a total bargain. So, I moved on to the idea of creating a green roof.

Green Roof Options
The two obstacles when building a green roof on a steep slope are: the weight of the roof and plants, and drainage—or too much of it. To combat both, I installed corrugated plastic sheets over the existing roof windows, and then explored ideas for creating level planting areas.

Rooftop Staircase
My first idea was to build a staircase-like structure that would sit over the roof and several levels of window boxes along the sides of the roof. I really like the idea of the planter boxes being removable like this. The drawback was trying to find window boxes of the right length or custom building some, which wasn’t out of the question, but then—Squirrel!

Vertical Garden Pocket Planters
Because green roofs and living walls (indoors and outdoors) are so popular right now, there are a lot of neat (and often expensive) related products available. I looked at a lot of pocket planters (you can see an example here), either made from recycled wool or plastics, but I couldn’t find anything the right size or price here in Canada. Again, the fun quickly wanes when the cost is too high. If you are in the United States, there are more reasonably-priced options.

Next, I looked at shoe bags, also known as shoe organizers. After all, the proper, commercial pocket planters are simply glorified shoe bags, really.

Over-Door Shoe Bags
I settled on some shoe bags from Amazon (the style intended for hanging on a closet door) that could be combined to match the dimensions of my shed roof. I knew they may not hold up for years on end, but it seemed worth the experiment. There weren’t a lot of options for materials and colours but the ones I chose are black with white mesh pouches and grommets for hanging.

See it at Amazon

The womp-womp occurred when the shipment arrived and I discovered the dimensions on the listing did not match the actual size. The actual shoe bags were longer and narrower than advertised, but I decided to adapt them. I ended up with some leftover sections which were near-enough perfect for my giant birdhouse, so it was all good in the end.

I’ll walk you through what I did and provide some tips along the way.

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Quick Overview

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Make a Simple Green Roof

Mini Greenhouse Green Roof

Here’s the mini greenhouse I built it a few years ago. The trick to making it really sturdy was to build a frame that the windows are attached to, instead of relying on the windows themselves to support the structure, since they are quite old and showing signs of age. You can see the entire building process here. I also added a tall stand so it would sit up and out of the snow.

Shoe Bags for Planters

I ordered four over-door shoe bags from Amazon (you can see the ones I got here). As mentioned, they weren’t the size listed but it all worked out in the end because I had spare sections to use on my old martin birdhouse.

See it at Amazon

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Prep Work

To get the greenhouse ready, I covered the roof windows in sheets of corrugated plastic. You can buy it at any home building store. I then installed screws near the peak of the roof on each side where the grommets from the shoe bags would go.

The shoe bags were measured on the roof and the excess bottom two rows of pockets were cut off and used later for my birdhouse (below).

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Cheap and Cheerful

The other cost-saving measure was to use flats of the lowest price annuals from a local nursey. My ideal would be to use cascading petunias and a few other trailing plants but it’s a bit early in the season to find them at a discount, so I went with regular petunias, begonias, and impatiens that were on sale.

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Why not perennials?

I intentionally used annuals instead of perennials because this style of green roof is temporary. I am experimenting to see how the shoe bags hold up, and, if I did add perennials, I would have to figure out how to winterize the whole thing, which sounds somewhat impossible or arduous to this Empress.

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Add Container Mix

I decided it would be easier to add the container mix and plants first, and then move the whole thing to the roof, instead of working up on a ladder.

In my potting area, I hung each shoe bag on a board and filled the pockets with container potting mix. This stuff is fluffy so you’ll need to press it down to avoid air pockets. This step is fairly time consuming—scooping soil into each pouch without making a complete mess.

Next, I added one or two annuals to each pouch (and forgot to take a photo as I was in the Happy Work Zone).

There were four shoe bags total to fill.

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Easy Installation

Because the screws were already in place, it was easy to climb a small step ladder and place the planted shoe bags in place. I then gave everything a nice, deep drink of water to get it settled in.

Grow On

Here it is on planting day. The hope, of course, is that the flowers are going to really fill out and give a lovely burst of colour up there during the summer months.

I’ll be watching to see if the rain and some hand-watering will keep things moist enough. I could add pieces of landscape cloth in each pocket to further retain moisture if needed.

Next, I used the leftover sections of shoe bag for the birdhouse roof (below).

Here it is a month later:

Birdhouse Green Roof

This is my old martin house which I bought for $10 a few years ago and totally love. It sits on a barstool as garden art. The critters love it too which is why all but one door is blocked off with wire. The chipmunks and the wrens were fighting for occupancy. After adding the wire, the occupancy battle settled down. Now, the wrens use it in spring, and the chipmunks move back in in autumn.

The leftover shoe bag sections were slightly narrower than the roof but I think they work just fine.

I used pinky-purple petunias and some cuttings from some garden ivy.

Again, I’m hoping the shoe bags keep enough moisture in that I won’t have to baby these guys, but only time will tell. For now, they already look pretty though the real show will come when the plants are much bigger.

If you try making your own shoe bag green roof, do let me know how it goes.

 

~Melissa the Empress of Dirt ♛