18-Inch Poly-Pro Plastic Flower Box Planter, Black. Constructed from a superior plastic blend, the Poly-Pro Flower Box and Liner boasts distinctive ridged panels to ensure ruggedness and sustainability. These versatile planters can be displayed as-is or used inside other planters as a protective liner. Built-in feet provide proper airflow and reduce the chance of water pooling under the planter. Suitable for indoor or outdoor use. When using outdoors, holes on the bottom of the planter should be punched or drilled out for proper water drainage. Poly-Pro Flower Boxes are lightweight, UV-protected, recyclable, and proudly made in the USA. Dims. (L"xW"xH") Soil Capacity* 17.75"x8"x5" 5 quarts 23.75"x8"x5" 6.7 quarts 29.75"x8"x5" 9.2 quarts 35.75"x8"x5" 11 quarts *Soil capacity measured in dry quarts, one inch from top of planter For best results and to promote healthy plants in a Poly-Pro Flower Box Planter: ? When using outdoors, be sure to punch out or drill the holes on the bottom of the planter to allow for proper water drainage. For additional soil aeration, add a soil amendment such a perlite, small stones, or clay pieces to the bottom?and up to 1/3?of the container ? When deciding what to grow in the flower box, check the planting instructions for the specific plant species. Follow the directions and, if planting multiple seeds or seedlings, place each plant the recommended distance between each plant to allow enough space between them to grow ? Position the flower box in an area that will receive the recommended amount of sunlight per the plant?s instructions ? Add potting mix to fill the container up to 1" from the top ? Water accordingly and often, especially in mid-to-late summer, high-temperature months. Ridged sides provide sturdiness and durability Constructed from lightweight, fade-resistant, and recyclable plastic Use as a standalone flower box or as a liner inside planters Made in the USA 17.75" L x 8" W x 5" H