Our molded plastic planters are made from high-grade polyethylene, double wall design * Sub-irrigation water system, encourages root growth * Inside dimensions are 13.75"l x 13.75"w x 13.5"d, approximately 8 gallon soil capacity (30 litres) * 15-year limited warranty. For more information please call us toll free at 866-363-8834. * Water reservoir capacity is approximately 6.5 gallons (24.6 liters)