Estimating the cost to fill your urban planter boxes depends on several key factors. First, calculate the total volume of soil needed. Measure the length, width, and depth of each box in feet and multiply these numbers (L x W x D) to find the cubic feet per box. Add the volumes for all boxes to get your total.
The primary cost driver is the type of growing medium. Basic topsoil is the most affordable, often ranging from $2 to $5 per cubic foot. A premium potting mix, which is lighter and offers better drainage and nutrients for containers, typically costs between $5 and $15 per cubic foot. Specialized mixes for vegetables or succulents may be higher.
Purchasing in bulk is usually far more economical than buying bagged soil. While a 0.75-cubic-foot bag of potting mix might cost $5-$10, a full cubic yard (27 cubic feet) of bulk garden soil can cost $30-$60, plus a delivery fee if you don't have a truck. Delivery fees can add $50-$150 to your total.
For example, filling a single 4'x2'x1' planter box (8 cubic feet) with mid-range potting mix could cost $40-$80 if using bags, or potentially $20-$40 if sourced from a bulk order. For a set of multiple boxes, bulk purchasing significantly reduces the per-cubic-foot cost.
To save money, consider a "hugelkultur" base of logs and branches to reduce soil volume, or mix your own blend using bulk topsoil, compost, and perlite. Always call local landscape supply companies for accurate bulk pricing and delivery quotes tailored to your specific project size and soil requirements.