Can You Use Styrofoam Coolers for Planters?

Cool Advantages From Using Coolers

• Polystyrene is tough, which means your planters will stand up to the cycles of sun, rain, wind and cold for years. They are also lightweight, allowing you to move them around easily even after you've planted in them, and you can pile them up for a vertical garden where space is limited. Adding a post or pole to tall stacks will help keep them upright during windstorms.

  Another benefit of using the coolers is they are insulated, which can protect tender roots from temperature extremes and can help hold moisture in the soil, especially if they are stacked. Finally, using foam coolers as planters keeps them from filling up the local landfill.

Preparing Your New Planter

• Foam coolers don't generally look attractive, but you can cover decals or stark whiteness with a little spray paint. Another option is to add a few plants that will tumble over the sides to hide the less attractive features. Before adding soil to your planter, be sure to add some 1/4-inch drainage holes in the bottom, spacing them about 2 1/2 inches apart.

Adding Your New Plants

• Like other containers, a foam cooler needs soil that drains well and is lightweight. Soil from the yard is generally too heavy for container plants, but commercial potting blends work well. You can also mix your own from equal parts of peat moss, garden loam and builder's sand. To give your plants the best start, add a slow-release general-purpose fertilizer to the soil before filling the cooler up to about 1/2 inch from the top. If you break the lid of the cooler into chunks and add them to the bottom of the planter, your planter will be even lighter for moving, and you'll need less soil. Wet the soil thoroughly before adding your plants. For best results, calculate the area of the container by multiplying its length by its width. Divide the answer by 36 to determine the maximum number of plants that will thrive in the cooler.

Keeping Your Plants Happy

• Polystyrene coolers won't hold a large volume of soil, which means the soil may dry out quickly. When the top 1/2 inch of soil is dry, give your plants a drink, adding water until it drains from the holes in the planter's bottom. Feed your plants with a few handfuls of compost about every three weeks to keep the plants healthy and happy.