How to Reuse a Cast Iron Tub in a Garden

Select an area for the tub that receives six to eight hours of direct sunlight daily. Tucked under trees that provide light shade in the late afternoon but receive bright morning light and direct sunlight during the day is ideal.

Place large boulders in the bottom of the tub. Although three or four are sufficient to provide drainage and hold roots above any water that may pool at the bottom of the tub, adding more reduces the amount of soil required to fill the tub. Consider placing plastic bins (like milk crates) upside down in the bottom of the tub if boulders are not readily available.

Fill the tub to within 3 to 4 inches of the rim with prepared soil. A mixture of equal parts all-purpose potting soil (or topsoil), perlite and peat moss makes a good soil for containers.

Select several tall plants for the center of the tub to create height. If the tub will be viewed from only one angle, place the plants toward the back of the tub; otherwise, center the plants. Brightly colored phlox or subtle pink astilbe make excellent choices. Phlox provide a heady, sweet fragrance in midsummer and astilbe creates a magical quality resembling soap bubbles floating above the tub.

Choose mounded plants to fill in around the center. Keep in mind the color scheme and choose blooms that complement the overall theme. Trumpet-shaped blooms in shades of red, orange or purple attract hummingbirds. Add brilliant cosmos, asters or marigolds for easy access for butterflies.

Plant trailing or vining flowers around the rim and allow to flow naturally over the side. Wave petunias, morning glories or trumpet vines provide a profusion of blooms that explode with color. Add ivies to add texture and variety to the bed.