I am part of a fortunate minority with a backyard in Brooklyn yet I still wanted to explore options that would help me to further utilize unused space in my yard. I got an email from Instructables.com with a simple way to convert a shoe caddy into a hanging wall garden. I thought it was brilliant and also inexpensive so I had no hesitation over giving it a go. You should too! This is a great solution for those with minimal space. If you simply have a wall outside that gets 8 hours of sunlight, this will work for you.
I basically ordered some canvas shoe caddies from Amazon.com for $7.00 a piece. When they arrived, we mounted them with screws and washers to the wall, filling them with a potting soil and compost mixture. We decided that we would fill them with herbs, lettuce mix and some more compact varieties of cucumber so that our evil squirrel neighbors would have a harder time getting to them.
We also chose to give one of those hanging canvas shelves a try, planting determinate (compact) varieties of tomatoes with basil planted between them.
These turn out to be working quite well.
The only drawback to this set up is that, since the caddies are not lined, the canvas is beginning to rot and split. You can purchase shoe caddies that are lined, but I was recently sent a Woolly Pocket and am excited to give it a try. The construction is quite sturdy, and the one I got is lined to it helps retain moisture. If your wall garden gets wet when it rains, I recommend getting one without lining so that the soil can dry out if it becomes over-saturated. I have to water my wall planters by hand so soggy soil should not be a problem. I would recommend to fill each pouch to about a half inch from the top in either pouch set up. The soil tends to tamp down and the extra fabric can block the plants from getting more sun.
All in all, I think this is one of the easiest, most fiscally and spatially economic ways to garden. You won't get a huge harvest, but its a great way to incorporate more herbs, greens, vining plants and even flowers into your space.