In short, our planter box factory can custom-build balcony planters for privacy screens, but the safe maximum height depends on whether you mean the planter body alone or the total screen height. As a standard guideline, a freestanding custom planter body should usually stay at or below about 1.2 m (4 ft). For a privacy screen, the total planter-plus-trellis or planter-plus-screen height can typically be designed up to around 1.8–2.0 m (6–6.5 ft). With reinforced aluminum or steel framing, concealed floor or wall anchoring, and an engineered wind-load calculation, a custom unit may occasionally reach about 2.4 m (8 ft), but this should not be treated as a stock, freestanding, or universally safe solution. The true maximum height is project-specific and must be confirmed by local building codes, balcony slab and railing capacity, wind exposure, waterproofing, drainage, planter weight when filled with wet soil, and safety requirements. For balcony privacy screens, we generally recommend keeping the total height within 2.0 m unless a structural engineer approves a taller design. Taller screens should use open or slatted sections to reduce wind pressure, and they must be anchored to the building structure rather than relying on the railing. The planter should also include proper drainage, a root barrier, lightweight planting media, and access for maintenance. If you want a privacy screen higher than 2.0 m, our factory can review drawings, balcony measurements, wind zone, and anchoring details before confirming a custom maximum height and safe specification.