Choose a level site with good sunlight and drainage
Check local building codes and permit requirements
Decide the greenhouse size and purpose
Select a frame material such as wood, aluminum, or galvanized steel
Select glazing material such as glass, polycarbonate, or polyethylene film
Mark the greenhouse footprint on the ground
Clear and level the site
Build a foundation or anchor system
Assemble the base frame
Install corner posts and structural supports
Add roof rafters and wall framing
Install bracing for stability
Attach the glazing or covering material
Seal joints and gaps
Install doors and vents
Add windows, fans, or automatic vent openers
Set up shelving, benches, or plant beds
Install irrigation or watering systems
Add heating, shading, and temperature controls if needed
Test the structure for leaks, stability, and airflow
Place plants and monitor conditions regularly