Several things should be considered in identifying the appropriate size and type of container for a gardening situation. From an aesthetic point of view, the container should fit nicely in the intended space, complement the surrounding architecture and landscape, and be attractive unto itself. Containers can be made from many materials, including clay, plastic, metal, concrete, or wood. They can be purchased or homemade. They can be created from objects designed for other purposes, such as wash tubs, troughs, or whiskey barrels.
Container selection should also entail consideration of plant growth requirements. It should be large enough to support healthy root and foliage development. It must have drainage holes in the bottom and/or sides to prevent soil saturation and water logging. The container must also be free of any residues that may be toxic to plants.
Adequate soil must be present in a container to supply all water and nutrient demands of plants. For that reason, minimum acceptable container size depends on the size and species of plant. Generally, containers should be at least one-gallon size. Anything smaller restricts plant growth and requires considerable labor to maintain adequate moisture and fertility.
The following rule of thumb, based on plant size and type, can be used to determine minimal acceptable container size:
- Small annual plants (3-8 inches tall) 1 gallon pot
- Medium annual plants (9-18 inches tall) 2 gallon pot
- Large annual plants (>19 inches tall) 5 gallon pot
- Small perennial plants (3-10 inches tall) 2 gallon pot
- Large perennial plants (>11 inches tall) 5+ gallon pot
- Woody plants (any size) 5+ gallon pot