That's an excellent question! To fill one of our extra-large urban planter boxes, you'll need to calculate its volume. Our standard extra-large box measures 48 inches in length, 24 inches in width, and 18 inches in height.
Here's the simple math: Multiply the length, width, and height (in feet) to find the volume in cubic feet. For this box: (4 ft x 2 ft x 1.5 ft) = 12 cubic feet.
Therefore, you will need approximately 12 cubic feet of soil to fill it to the brim. We recommend using a high-quality potting mix designed for containers, as it provides proper drainage and aeration. Remember, you don't always need to fill it completely—leaving a couple of inches at the top makes watering easier. For best results, consider a blend of potting soil and compost. Always purchase a little extra soil, as it will settle after the first few waterings.