Buy an outer planter that suits the nursery pot
An outer planter should leave room for the nursery pot and a way to manage drainage. Measure both the rim and the base before buying.
Take the plant out of its current decorative container and look at the nursery pot underneath. Its rim may flare wider than the body, and its base may sit on raised feet. Measure the widest point and the height, including any attached saucer. Those are the dimensions the outer planter needs to accommodate, not the spread of the leaves.
An outer planter, or cachepot, can hold the nursery pot without becoming the planting container itself. That arrangement makes it possible to lift the plant out for watering when appropriate. If you want to plant directly into a pot instead, check drainage and the plant's requirements separately; a decorative vessel without drainage is not interchangeable with a nursery pot.
Leave room to lift the plant
Compare the planter's internal opening and depth with your measurements. Thick walls and a narrow neck can make the interior smaller than the outside suggests. A pot that slips in tightly may be difficult to remove later, especially with a heavy plant or spreading foliage. Leave usable clearance rather than selecting the closest possible numerical match.
Look at where the nursery pot will sit. If it disappears too far below the rim, foliage may press against the edge. Do not fill the bottom with an improvised layer and assume that solves drainage. Use an arrangement suitable for the plant and container, and prevent the nursery pot from sitting in accumulated water when that would be inappropriate for the plant.
Consider the surface underneath
Check whether the decorative pot is watertight and intended for indoor use. Some materials can transfer moisture or mark furniture even when no obvious puddle appears. Use appropriate protection and inspect beneath it regularly. A saucer that fits inside the outer pot still needs to be emptied or managed according to the plant's watering needs.
For a high shelf, account for the combined weight of plant, soil, container and water. For a floor position, make sure the planter does not narrow a route or tip easily when brushed. Once the functional size is settled, choose the color and texture. A well-fitting outer pot should make care easier to carry out, not make the plant harder to remove whenever it needs attention.
