By Nicole Galipeau
Strawberries are great plants for small gardens, and are one of the few berry varieties that consistently grow well in containers. In fact, just about anything you have lying around can be made into a strawberry pot. Galvanized metal tubs are popular options for container planters, but in the case of edible foods, precautions must be taken to ensure that the rusty metal does not leach harmful substances into your soil that can be absorbed into the plants.
Rinse any dirt, debris and loose rust particles with a hose on a high-pressure setting. If you don’t have a hose sprayer with a pressure setting, the old thumb over the opening trick works just fine.
Punch several holes into the bottom of the container with a hammer and wide nail. A grid pattern of small holes every 3 to 4 inches in each direction works best for thorough drainage.
Scrub the inside of the container with a mild solution of lukewarm water and dish soap—about two drops per gallon—and a steel wool scrubbing pad. Knock as much of the loose rust free as possible.
Rinse the metal container completely clean. Let it dry overnight.
Purchase a clear polyurethane or automotive sealer from the local hardware store. Automotive-rated spray products generally work to inhibit further rusting, and work well where items (such as your container) will be exposed to water. Polyurethane clear coats also work well, but are more widely available and often less expensive. Both act to inhibit the formation of new rust and protect your strawberries from chemicals while allowing the rust finish to show through.
Spray on the sealer in several quick, light coats, and allow the product to dry thoroughly between each layer, according to instructions. The protection on the outside will prevent the containers from degrading entirely over time, and can be applied more lightly. The inside coat, however, should be thick enough to thoroughly coat the interior of the metal. Let the protection dry for 24 hours.
Fill the container with a 2-inch layer of gravel for drainage. Add a high-quality potting mix that has been heavily amended with compost or a vegetable-grade fertilizer. Plant strawberries 8 to 14 inches apart for short-day varieties, or as close as 6 to 8 inches for ever-bearing and dwarf varieties.
If the container is exceptionally rusted or corroded and you are still concerned about chemicals hurting your strawberries, then add an extra layer of protection by placing a sheet of heavy-duty plastic into the container after you add your gravel, but before you place the soil. Make sure that you punch plenty of drainage holes into the plastic.