01
9.1 /10
Backyard Discovery Bellerose XL 13' x 11' …
Best for permanent, premium garden installs
- 13 × 11 ft (143 sq ft) Listing
- cedar wood Document
- polycarbonate Listing
Independent · Evidence-labeled · US marketplace
Vol. 01 — 2026
Find your space to grow.
Precision tools, honest comparisons and Evidence you can inspect. We show what's documented — and say so plainly when it isn't.
Listing sourced
Document verified
Hands-on tested
Not published
The toolkit.
Eleven instruments, each built around a single question buyers actually search — and each ending with gear that fits.
Sizing · 30 sec
Greenhouse Size Calculator
Size the footprint from what you actually want to grow.
Climate · 45 sec
Heater BTU Calculator
Find the exact heat output to hold your target temperature.
Climate · 30 sec
Ventilation Calculator
Right-size an extractor fan so summer heat never builds up.
Climate · 30 sec
Shade Cloth Calculator
The right shade density and how much fabric to buy.
Climate · 45 sec
Heating Cost Estimator
Estimate what a season of heating will actually cost you.
Growing · 30 sec
Raised Bed Soil Calculator
How much soil (and how many bags) your beds need.
Growing · 1 min
Seasonal Grow Calendar
Month-by-month sowing tasks tuned to your USDA zone.
Choosing · 1 min
Find My Greenhouse
Answer three questions, get a matched recommendation.
Choosing · 2 min
Comparison Builder
Put up to three greenhouses head-to-head, spec by spec.
Choosing · 1 min
Polycarbonate vs Glass
See the glazing trade-offs side by side, with evidence.
Choosing · 1 min
Roofline Selector
Pick the roof shape that fits your snow, wind and light.
Measure twice, buy once.
Our sizing instrument, live. Drag the sliders — the section drawing and the recommendation move with you.
Tell us what you want to grow. We size the footprint from documented bed, shelving and walkway allowances — never a round-number guess.
Raised beds · 4 × 8 ft
08
Potted / shelf plants
0120
Potting bench
Walkway comfort
ƒ
footprint = (beds × 20 + pots × 0.9 + bench 24) × aisle factor
Authority is earned in the details.
Every specification on this site carries an evidence label. We show what a manufacturer states, what an independent source confirms — and what simply isn't known.
Listing sourced
Captured from a live product listing on a stated date. It reflects what the seller says — not independent testing.
304
Document verified
Traced to a manufacturer document — a manual or specification sheet — and linked at the source.
29
Hands-on tested
Reserved for documented trials with published methods. We only use it once a real trial has taken place.
0
Not published
The manufacturer doesn't state it. It stays unknown — never a guess, a zero, or a hidden 'verified' badge.
7
0
340
4
Editor's picks.
Ranked by documented fit for your space, climate and budget — never by commission. Every value carries its evidence label.
01
Permanent, premium garden installs
Listing sourced
02
Large families and long-season growing
Listing sourced
03
Serious hobbyists with a mid-size yard
Listing sourced
06
Balconies and first-season growers
Listing sourced
01
9.1 /10
02
8.4 /10
Outsunny 20' x 8' Polycarbonate Greenhouse
Best for large families and long-season growing
- 20 × 8 ft (160 sq ft) Listing
- aluminum Document
- polycarbonate Listing
03
8.2 /10
Garvee 8 x 12 ft Outdoor Polycarbonate Gre…
Best for serious hobbyists with a mid-size yard
- 8 × 12 ft (96 sq ft) Listing
- aluminum Listing
- polycarbonate Listing
04
7.9 /10
6x10 FT
Best for a first permanent greenhouse
- 6 × 10 ft (60 sq ft) Listing
- aluminum Listing
- polycarbonate Listing
05
7.2 /10
VEVOR
Best for season extension on a tight budget
- 9.6 × 6.4 ft (61 sq ft) Listing
- galvanized steel Document
- PE Listing
06
6.8 /10
OLIXIS 56"x56"x77" Outdoor
Best for balconies and first-season growers
- 4.7 × 4.7 ft (22 sq ft) Listing
- Not published Not
- Not published Not
Side by side.
Pick up to three. What the manufacturer never published stays visibly unpublished.
Three questions. One match.
Space, budget, permanence. Sixty seconds to a documented recommendation.
Match found
Your best fit, on the evidence.
Scored on space, budget and permanence — never commission. Not convinced? .
A reason to return.
Your greenhouse rhythm, month by month — tuned to when frost actually leaves your zone.
The journal.
Evidence-first guides and instruments that earn their rankings and route readers to the right gear.
Best Greenhouses of 2026
Six documented picks across budgets, with what each manufacturer won't tell you.
How to Size a Greenhouse Heater
The BTU math, worked examples, and the vents that quietly waste your heat.
Polycarbonate vs Glass Glazing
Light transmission, insulation and cost — the evidence side by side.
Questions, answered.
Size to what you grow plus walkways: allow ~20 sq ft per raised bed, ~0.9 sq ft per potted plant on shelving, and multiply by 1.2–1.6 for aisles. The size calculator does this instantly and draws the section for you.
Twin-wall polycarbonate insulates far better and won't shatter, at some cost to clarity. Glass gives the best light transmission and longevity but is heavier and pricier. The glazing chooser lays the evidence side by side.
Multiply the total surface area by your inside–outside temperature difference and a U-factor for the glazing. The BTU calculator runs the full formula across every surface.
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