Two years ago this month I took a big black plastic tree pot, pulled used grocery bags through every drainage hole from the inside out to restrict drainage yet allow air flow to enable roots to absorb oxygen at night as they need to. Then I added compost, a chunk of broken concrete block near the bottom as a calcium source and possible nematode deterence, added more layers of soil and organic matter, then planted the rose "Fairmount Red" I discovered in 1989 in Denver's Fairmount Cemetery, that I loved in my Denver yard but that had died in my Tampa yard twice, and quickly. But in this restricted drainage pot it took off, and in defiance of logic and our mild winters here, despite it being a once-bloomer comprised almost entirely of new growth vs. older wood, it bloomed last March at one year of age!!!
A few years ago I started experimenting here to try to deal personally with the south Tampa rain shadow, and also to try to understand so many of my readers had e-mailed over the years with their poor results with their Earth Boxes. The end result was the Water Wise Container Garden I now rely on almost completely for my beloved roses, and also very greatly for food gardening. I am writing an article about this life changing approach to gardening I wish I'd thought of twenty years ago, for 'Florida Gardening', and I teach classes about them here at home.
A large commercial black plastic tree pot, similar to the one in the photos, and filled with homemade soil, is letting me grow carrots, a thirsty crop that gets bitter when underwatered, easily and watered exclusively by rain water I catch off my roof eaves with 5 gallon buckets. Whenever I position one of these Restricted Drainage Pots in my yard, I mulch around it with a few inches of leaves or chipped tree mulch, to hide the unsightly bags protruding from the drainage holes.
I love this concept because it works well for me, (and I fully expect it will for other gardeners) costs little or nothing, is based almost wholly on recycling, and can be used on any flower pot or container that has its drainage holes at the bottom. Plug those holes up with plastic grocery bags, add good soil, plant your plant, and expect great growth and greatly reduced watering.
I'd love to hear from folks about their having tried this out, plus their own variations on the theme.
Water is growing only scarcer all over this teensy planet.....seeing how much one can cut back on water use can be a fun obsession that saves money and contributes to global healing.