At our planter box factory, the tallest planter we can produce without requiring a custom mold is 1.2 meters (approximately 4 feet). This limit is determined by the standard mold dimensions of our high-pressure injection and extrusion lines, which are engineered to maintain uniform wall thickness, structural integrity, and surface finish at this height. Going beyond 1.2 meters would typically necessitate a bespoke mold to ensure proper material flow and cooling, especially for polymer-based planters that are prone to warping. However, for taller applications, we offer a modular stacking system where multiple 1.2-meter sections are mechanically joined with internal braces and drainage-compatible connectors. This approach achieves heights up to 3.6 meters without any custom tooling, while preserving the clean look of a monolithic planter. Our factory’s standard 1.2-meter planter is made from UV-stabilized polypropylene or fiberglass-reinforced composite, both of which provide excellent load-bearing capacity for deep-rooted plants. The tooling geometry also includes a slight taper from top to bottom, which aids in demolding and allows the units to nest efficiently for shipping. In short, if you need a tall planter straight from an existing mold, 1.2 meters is your answer; for greater heights, our proven modular solution extends that limit without sacrificing durability or aesthetics.