In short
Every pick is research-based. We compare published specifications, check prices at several retailers, and read owner reports from forums, Reddit and retailer reviews. We have not assembled these greenhouses ourselves, and we never say we have.
What we compare
| Criterion | Why it matters | Where the data comes from |
|---|---|---|
| Cover material and thickness | Twin-wall polycarbonate insulates far better than single-wall panels or film, which changes heating costs and frost protection. | Manufacturer spec sheets |
| Frame | Aluminum and powder-coated steel resist rot and rust; the profile decides how rigid the structure is in wind. | Spec sheets, assembly manuals |
| Snow and wind ratings | The most common failures are panels blowing out and roofs buckling under snow. | Published ratings (we say so when a maker doesn't publish one) |
| Ventilation | Overheating kills more plants than cold. We count roof vents, louvers and door options. | Specs, product photos, manuals |
| Base and anchoring | A kit is only as strong as what it's bolted to. | Manufacturer installation guides |
| Assembly reality | Instructions, missing parts and build time drive most negative reviews. | Owner reports on Reddit, gardening forums and retailer reviews |
| Price and availability | Prices swing a lot between retailers and seasons. | Major retailers, checked on the date shown on each page |
How we pick
- Define the job Each page answers one buying question (a size, a type, a budget). We only compare greenhouses that fit that job.
- Collect the specs From the manufacturer first, then retailer listings. Conflicting numbers are checked against the manual.
- Read the owners We look for patterns, not one-off complaints: panels popping out, leaks, rust, missing parts, how long assembly took.
- Weigh value A cheap kit that lasts one season isn't a bargain. We point out when spending more is worth it, and when it isn't.
- Re-check Prices and models change. Each page shows when it was last updated.
What we never do
- Claim we tested or assembled a product when we didn't.
- Accept payment for a pick or a position on a list.
- Invent specifications, ratings or prices. If a number isn't published, we say so.
Prices on this site are typical ranges, not live prices. Always check the retailer before you buy. Questions about a pick? Tell us.