A portable greenhouse offers a flexible solution for gardeners with limited space, those needing seasonal protection, or individuals who want to maximize sun exposure by moving the structure. This design extends the growing season by creating a microclimate that shields plants from harsh weather. Unlike permanent structures, a portable model can be easily disassembled for storage or relocated, making it practical for urban settings or rental properties. The core concept involves selecting lightweight materials and engineering a frame that balances structural integrity with mobility.
Essential Design Choices and Materials
The design of a portable greenhouse requires three interconnected decisions: the frame, the covering, and the connection methods, which dictate the structure’s portability and durability. Frame options typically use polyvinyl chloride (PVC) pipe or thin-walled galvanized metal conduit, both lightweight and readily available. PVC is simple to cut and join, making it popular for temporary or smaller structures, though metal options offer greater strength and longevity.
Metal conduit, while slightly heavier and requiring specialized fittings, offers superior strength against wind and snow loads, making it suitable for extended seasonal use. The structure’s final size is a primary constraint; a small footprint, such as a 4×8-foot base, significantly improves ease of movement compared to a larger walk-in model. Covering material choice affects weight and performance. UV-resistant polyethylene plastic sheeting (typically 6-mil thickness) is the lightest and least expensive option, ideal for high-mobility designs.
Polycarbonate panels, especially twin-wall sheets, provide better insulation by trapping air between layers, which is beneficial for colder climates. However, they add substantial weight and rigidity to the frame. Connection methods must prioritize ease of breakdown: specialized PVC fittings allow for slip-fit joints rather than permanent solvent cement, and quick-release clamps are used for metal frames. Using zip ties or plastic clips to secure the covering allows for quick removal and reattachment.
Step-by-Step Assembly Instructions
Construction begins by accurately measuring and cutting the frame material to establish the base and arch supports. For a PVC hoop house, the base frame pieces are cut to the desired length and width, while arch pieces are cut longer to be bent into a semi-circular shape. Using four-way or three-way corner connectors, the base is assembled first, ensuring it forms a true rectangle to prevent structural twisting.
The arches are then secured to the base, often by inserting the pipe ends into ground sleeves or larger diameter PVC sections attached to the base frame. Secure these joints with screws or non-permanent pins to maintain the ability to disassemble the frame later. Longitudinal supports, such as a ridge pole running along the top, are then added. This prevents the arches from collapsing inward and provides a surface for attaching the covering.
With the skeleton complete, the covering material is stretched over the frame, starting from one end and pulling taut to minimize wrinkles that could collect water or catch wind. Specialized plastic clips, spring clamps, or wood lath strips secured with screws hold the plastic firmly to the frame members. Access points are created by cutting the plastic in a large “U” or “I” shape on an end wall. The edges are then secured with battens or grommets, allowing the plastic to be rolled up and tied for ventilation. Ensure the plastic is sealed tightly at the base to trap warmth and humidity.
Ensuring Stability and Mobility
Once the portable greenhouse is built, maintaining its structure against wind is a primary concern, addressed through temporary anchoring methods. For structures placed on soil or grass, ground stakes or corkscrew-style earth anchors are driven near the base of the frame and connected using rope or strapping. If the base rests on a patio or deck, stability is achieved by placing heavy objects directly onto the bottom frame rails. These objects include:
- Sandbags
- Cinder blocks
- Large gravel bags
For smaller or lighter designs, stability can be enhanced by securing the structure to a wood or plywood base that is then weighed down. Mobility is achieved by incorporating features that facilitate relocation without disassembly. A common approach is to bolt heavy-duty, lockable swivel casters to the corners of a permanent lumber base frame, allowing the entire structure to be rolled.
For models without a permanent base, handles can be attached to the frame ends, allowing two people to lift and carry the greenhouse. Lockable casters are important because the brakes prevent unintended movement caused by wind. This ensures the greenhouse remains precisely where it is placed until it needs to be moved to follow the sun or avoid severe weather.