A 5-gallon container is a standard sight in gardening, used for everything from nursery stock to large vegetable plants. The volumetric measurement offers little practical information for gardeners planning space or purchasing materials. Understanding the true size requires translating the labeled capacity into physical dimensions like height and diameter, which allows for accurate planning of garden layouts and calculating necessary soil amounts.
Standard Physical Dimensions
The physical size of a 5-gallon nursery pot follows a standard range of dimensions. A typical round 5-gallon container has a top diameter of approximately 11 to 12 inches (28 to 30.5 centimeters) and a height between 10.5 to 11.75 inches (26.7 to 30 centimeters). These measurements define the pot’s footprint and vertical profile, which is important for fitting them onto shelving, in garden beds, or on patios.
The bottom diameter is slightly smaller than the top, creating a tapered shape. This taper is designed for efficient nesting during storage and easier removal of the root ball when transplanting. Knowing these dimensions helps visualize the space occupied; for instance, a row of five pots requires a minimum length of about five feet (152 centimeters).
Why a 5-Gallon Pot Isn’t Exactly 5 Gallons
The label “5-gallon pot” uses the “Trade Gallon” standard common in the horticulture industry, which is distinct from a true U.S. liquid gallon. This commercial classification system means a container labeled as a #5 often holds less than five actual liquid gallons of soil.
The actual volume of a labeled 5-gallon nursery pot ranges from 3.5 to 4.5 US liquid gallons, or approximately 13.2 to 17 liters. This discrepancy reflects historical practices and ensures compatibility across different growers and suppliers. The #5 designation is essentially a size category indicating the relative maturity of the plant inside.
Calculating Soil Volume and Container Weight
Converting the container’s volume into a usable measure for purchasing potting mix is necessary for gardeners. A true 5-gallon volume converts to approximately 0.67 cubic feet. Since the actual capacity of a trade 5-gallon pot is less, the required soil volume is closer to 0.54 to 0.66 cubic feet (about 15 to 19 liters) of dry potting mix per container. This calculation is necessary when buying bulk soil, which is typically sold by the cubic foot or liter.
The resulting weight of a filled container is an important consideration for mobility and structural support. A 5-gallon pot filled with a standard potting mix and fully watered can weigh between 30 and 45 pounds. This weight is dependent on the soil composition and moisture level. For instance, soil mixes heavy in peat moss or coco coir are lighter than those with a high content of dense topsoil or clay, which can approach the higher end of the weight range when saturated.
What Plant Size Can a 5-Gallon Pot Support?
The 5-gallon pot size offers a balance between sufficient root space and manageable container size. This volume is appropriate for growing a single, full-sized vegetable plant, such as a determinate tomato or a mature pepper plant. It retains the necessary water and nutrients to support the root system for a full growing season.
The container is also used for the intermediate growth stage of larger plants, including young shrubs, small fruit trees, or roses, before transplanting. The limited volume restricts the overall root mass, which limits the plant’s ultimate canopy size and yield compared to growing in the ground. For perennial or woody plants, the 5-gallon size allows them to reach a height of 12 to 54 inches before they become root-bound and require transplanting.