Measure the installation space in three dimensions
Begin with the clear width and length of the proposed site, then measure any height restrictions under branches, fences or eaves. A roof vent or opening door may need more clearance than the structure itself. Do not rely on a single footprint printed in a feed, especially if the units look inconsistent.
Allow room to walk and maintain the structure
A greenhouse is easier to use when you can access the door comfortably and clean or maintain the exterior. Consider where you will keep watering equipment and where a door swings. Nearby walls can make ventilation and glass replacement difficult.
Understand the foundation requirement
Rigid aluminium frames need a suitable level base and manufacturer-approved anchoring. Some packages include a foundation frame; others sell the base separately. A foundation component is not the same thing as a completed, safe ground installation. Check drainage, ground conditions and the exact installation instructions.
Ventilation matters from day one
Small growing structures can overheat quickly in direct sun. Compare roof and side vents, door access and how covers are opened. A temporary PE-covered greenhouse behaves differently from rigid glazed structures, and you should check whether the product is intended for seasonal use only.
Review weather exposure and local rules
Wind, snow and falling branches can damage inadequately secured greenhouses. Use the manufacturer wind and load instructions and consider exposure on your site. Where relevant, check tenancy, lease, allotment or local planning rules rather than assuming every garden structure is unrestricted.
Check the source units before ordering
Retailer data feeds sometimes contain distorted unit labels. If a greenhouse is presented as several feet tall but the listed dimensions do not make sense together, consult the current product page, product diagram or manufacturer manual. Our greenhouse comparison intentionally avoids treating ambiguous feed dimensions as verified facts.