Choosing a greenhouse
6×8 vs 8×10 vs 8×12 greenhouses
The extra two feet are not just more square footage: they can create a workable aisle, a real bench, or room to work.
Short answer
Choose the smallest footprint that still supports how you will work, not just the number of trays you hope to fit. Deduct benches, aisles, doors, heater clearance, and working space from the exterior rectangle.
Exterior is not usable interior
Manufacturers usually describe the outside footprint. Walls, framing, doors, vents, benches, and clearance reduce usable space. Draw the things that cannot move: door swing, aisle, tall crops, work surface, and equipment.
What changes between sizes
- 6×8: focused seasonal work, with little layout slack.
- 8×10: a more forgiving hobby footprint.
- 8×12: more breathing room, but more base, cost, and exposure obligations.
The honest test
Mark the exterior dimensions in the real yard with string. Add delivery and door approach. Imagine the busiest week, not the empty-house photo. If everything fits only by removing the aisle, the size does not fit the job.
Common mistakes
- Using square footage without circulation.
- Forgetting door, wall, roof, and foundation clearance.
- Choosing the largest size without pricing the larger base and freight.
- Assuming plants will stay small.
A judgment call
Between 6×8 and 8×10 for seedlings plus mature plants, I would favor 8×10 if the site and budget can carry it. A deliberate 6×8 is better than an overcrowded 8×10.