What Size Greenhouse Do You Need? A Size Guide From Hobby to Commercial

TMG Industrial Australia's greenhouse range runs from small hobby tunnels through to 25-metre commercial structures, and picking the wrong size is the easiest way to either outgrow a greenhouse in a season or overspend on space you'll never use. Here's how to size it correctly.

Match the Greenhouse to Your Growing Goal, Not Just Your Yard

Hobby or backyard growing — a smaller tunnel greenhouse gives season extension and protection for a home vegetable patch without a large footprint.
Market garden or small commercial — a mid-size tunnel greenhouse supports serious production volume while staying manageable for one or two people to run.
Commercial-scale operations — the largest tunnel greenhouses in TMG's range are built for continuous production runs and multiple growing beds.

Comparing the Size Range

Size tier	Footprint	Example model	Best for
Entry hobby	3 × 6 m	TMG-GH1020R	Backyard vegetable growing, season extension
Small hobby / market garden	3.7 × 9 m	TMG-GH1230	Growing for a household or small market stall
Mid-size	7.6 × 12 m	TMG-GH2540-V2	Small commercial or serious market garden production
Commercial	9 × 12 m	TMG-GH3040-V2	Continuous commercial production
Walk-in kit style	2.4 × 6.1 m	TMG-GH821	Solid polycarbonate roof/walls instead of a poly tunnel cover — a different structure type for smaller spaces

For a deeper comparison of the two largest commercial models (including poly cover thickness and material), see our existing guide: How Clear Poly Covers Enhance Growth in Commercial Tunnel Greenhouses.

Tunnel Cover vs. Polycarbonate Kit

Most of TMG's range uses a clear poly/EVA film tunnel cover over a steel frame — lighter, more affordable, and easy to replace when it wears out. The TMG-GH821 is different: a walk-in kit-style greenhouse with a rigid polycarbonate roof and clear walls, closer to a traditional garden greenhouse structure. It suits smaller spaces where a permanent-feeling structure matters more than tunnel-style flexibility.

Sizing Mistakes to Avoid

Undersizing for growth — market gardens especially tend to expand production faster than expected; a size up front avoids a second purchase within a year or two.
Ignoring site access — larger tunnel structures need clear, level ground and enough clearance to erect the frame; check your site before ordering.
Skipping ventilation planning — roll-up sides are standard across this range, but larger structures need more attention to airflow to avoid overheating in an Australian summer.

Frequently Asked Questions

What's a good starter greenhouse size for a home vegetable garden? A 3 × 6 m tunnel (like the TMG-GH1020R) is enough for most home growing without becoming difficult to manage or maintain.

How much bigger should I size up if I'm planning to sell produce? There's no fixed rule, but market gardens commonly move to the 7.6 m-wide tier for the extra bed space and headroom needed for consistent production volume.

Is a polycarbonate greenhouse better than a poly tunnel cover? Neither is universally better — polycarbonate (like the TMG-GH821) feels more permanent and is more impact-resistant, while poly tunnel covers are lighter, cheaper to replace, and suit larger footprints more economically.

Final Word

Size a greenhouse to where your growing plans will be in a year or two, not just where they are today, and match the structure type (tunnel cover vs. polycarbonate) to how permanent you need it to feel. Browse the full range in the Greenhouses collection, or get in touch with the TMG Industrial Australia team to talk through your growing space.

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