Choosing a greenhouse
Polycarbonate vs glass vs greenhouse film
Choose the covering as part of the structure, climate, maintenance plan, and budget—not as a finish picked at the end.
Short answer
Glass can offer clarity and long life but is heavy, costly, and impact-sensitive. Rigid polycarbonate is lighter and impact-tolerant, with performance depending on panel construction. Film is lightweight and economical but needs correct greenhouse-grade material and more frequent replacement.
The tradeoffs that matter
NC State Extension identifies glass, rigid double-wall plastics, and film plastics as common coverings with different lifespans and structural implications. WSU highlights film’s low cost and easy installation alongside tear and replacement risk, while rigid polycarbonate is strong and lightweight but more expensive and translucent.
Match material to the job
| If you value… | Investigate… |
|---|---|
| Clarity and permanence | Glass, with stronger framing and impact considerations |
| Balanced durability and insulation | Rigid polycarbonate construction and warranty |
| Low initial cost or seasonal flexibility | Greenhouse-grade film and replacement plan |
The climate connection
Covering affects heat loss, overheating, light, and storm behavior. In winter, glazing cannot substitute for heating and site planning. In hot climates, the best covering still needs ventilation and shade management.
Common mistakes
- Treating “poly” as one material.
- Using hardware-store plastic instead of greenhouse-grade film.
- Choosing glass without pricing the stronger frame.
- Assuming thicker panels solve all structural concerns.
A judgment call
For a short seasonal project, film may be honest value. For a permanent backyard structure, compare panel construction, warranties, and frame evidence together.