When I wrote my book Modern Pioneering, it was to encourage and inspire the use of our hands no matter what kind of space you live in, because most of us don’t live with a lot of land around us. Sometimes all we have is a windowsill, or a back alley, or a fire escape, or a vacant lot! I recently did a makeover of a small outdoor space that really made the most of container gardening in all of its forms. So I wanted to share 8 Tips for Outdoor Container or Roof Gardening so that you have a smashing success when you do it yourself and don’t feel at all intimidated. There are tremendous advantages to container gardening which I’ve written to you about here before, so I hope you’ll try at least something small this season to get your toes wet. I promise once you start you won’t be able to stop.
8 Tips for Outdoor Container or Roof Gardening:
Use Specific Container Soil
Use soil that is specifically intended for container gardening. It will be lighter and have better drainage to help prevent the soil from drying out quickly from wind and sun. A good container soil will have a balance of organic compost, something to aerate the soil like sawdust, sand, or humus and a fertilizer.
Container Depth Matters
For growing vegetables use boxes that are at least 8 inches deep. Herbs and flowers can be in shallower containers.
Treat Wooden Containers
Boxes should be as wide as the space will allow in addition to 8 inches deep, and should have ½-inch drainage holes at the bottom every 5 to 6 inches. Cypress and redwood are good durable woods; you can also use oak. Just make sure none of the wood you use is treated with chemical preservatives, which will leach into the soil. The insides of wooden boxes do best when you paint them with a wood preserving material like asphaltum, which is a natural tar-like substance that creates a waterproof coating and can be purchased at home-improvement stores. You can also purchase paraffin, spray it on the wood, and burn it off with a blowtorch. This locks it in the cell walls of the wood to prevent leaching. The outsides can be painted as desired.
Use a Lighter Material for Windowsills
If you need a lighter load for your windowsill, use a lightweight container like resin, fiberglass, or plastic as well as a light soil designed for container gardening.
Think About Your Bottom and Top Layers
If you would like, you can add a layer of straw, leaves, and other light matter to improve drainage at the bottom of the pot. Rocks and shells aren’t necessary. The top layer should have good-quality manure, loam, and mulch to finish.
Buy One Size Larger Than You Need
Container gardening soaks up a lot of water, and the smaller the containers are, the more often they will need water. If you buy a pot size bigger than you need, this will give you a bit more breathing room in how often you have to water. Also, the plant will only grow as large as the container it is in. So give it room to grow by buying a pot larger than it initially requires.
Skip the Saucers Under Pots
Always use a container with a drainage hole, and avoid the saucers that go under pots since they will capture the water and rot the roots if not emptied. If you are worried about stains without the saucer, buy planters with legs, or a rolling platform, then set a small saucer underneath the dolly legs to catch the water.
Use This Solution to Clean Containers Before Reusing Them
When reusing growing containers year after year, make sure you clean them well before planting for a new season. Diseases and pests can linger in pots from previous years, which will prohibit a healthy crop, especially when you are starting from seed. Soak the containers overnight in 9 parts water to 1 part bleach, then let them sit out to dry before planting.