A transplantable plant container assembly is provided for containing a growing medium for a plant that significantly promotes air root pruning. The container assembly includes a container device that includes a sidewall support and a bottom support collectively defining an interior cavity. The sidewall support is comprised of a lattice framework defining a plurality of spaced apertures that extend from an interior wall to an exterior wall thereof. A relatively thin, moisture absorbent liner material is disposed adjacent to the lattice framework. The liner material is sufficiently penetrable to enable root penetration therethrough, by the plant, at the apertures. However, the liner material must also have sufficient structural integrity, when moist, to bound the growing medium and moisture across the spaced apertures of the lattice framework when contained in the interior cavity.