Answer: Key limes can eventually reach 10 feet or more in ideal situations. However, in containers they tend to only reach the 4 to 6 feet range. Depending on the size of tree you start with, you may be able to get by with a 5-gallon pot for a season or two. Then move the tree up into larger pot sizes as it grows.
In a few years it could even be placed in a container the size of a half whiskey barrel, although a slightly smaller size pot would also work satisfactorily. Whatever container you choose, it needs to be movable so that it could be brought indoors for winter protection.
Keep you key lime adequately moist but not soggy-wet. Fertilize with either a slow release product like Osmocote (early spring and early to mid summer) or a liquid fertilizer like Miracle grow (spring through late summer at the weekly label rate).
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