THE GUIDE / choosing
Polytunnel vs greenhouse: compare the job, not the label (UK)
Compare a tunnel and a greenhouse against one growing plan, including access, upkeep and the information to request before buying.
Choose the structure that can accommodate the growing plan and the work you are prepared to do. A tunnel-versus-greenhouse argument is not much help until the two actual models are measured against the same job. Neither label answers every question about usable space, access or replacement parts.
This is a decision method, not a claim that one category is always warmer, cheaper or more durable. Those comparisons need the specifications and instructions for the products being considered.
Write a short job description
“More growing space” is a start, but it leaves too much undecided. Write down what the structure must let you do. For example: grow in beds, keep a particular collection of pots, use staging, or move equipment through a door without lifting it.
Separate essentials from preferences. A door that will not admit your equipment is a failed requirement. A colour you dislike is a different sort of objection. Keeping those apart makes the comparison less vulnerable to a good photograph or an attractive headline figure.
Draw the intended beds and paths once, then use that same drawing for both options. The size calculator can help with the rectangular layout, although it is not a product-fitting check.
Compare two named models on the same sheet
Ask each supplier for the dimensions and instructions for the exact model, size and options in the quote. Do not compare a tunnel’s external outline with a greenhouse’s clear growing area, or one standard package with the other’s optional extras included.
A useful comparison sheet has five rows:
| Question | Evidence to request for each option |
|---|---|
| Will the layout fit? | Dimensioned drawing, including usable width and height where equipment will sit |
| Can I get in and work? | Clear door opening, opening direction and access to the planned beds |
| How is it installed? | Model-specific instructions, required site preparation and the specified fixing method |
| What will I maintain? | Care instructions, replaceable components and how to identify the right spare |
| What is included? | Written list of supplied components, chosen options and exclusions |
Leave a blank where an answer is missing. A blank is a question for the supplier, not an invitation to fill the gap with a category-wide assumption.
Materials are a specification, not a promise
Record the actual covering or glazing material in the product description. Then read the care and replacement instructions for that material and model. Avoid turning a single feature into an overall verdict: a material name alone does not tell you how the complete structure will fit your routine.
Ask how damage is dealt with, how a replacement is identified and whether fitting instructions are available before purchase. If the answer depends on an accessory, put that accessory on the comparison sheet too.
No material lifespan or performance figures are asserted here. Published figures need a dated official source and a clear explanation of what they cover before they belong in a buying recommendation.
Think through an ordinary week
Imagine arriving with the things you normally carry. Where do they go while the door is being opened? Can you reach the growing area you have drawn? Where will watering equipment run, and will it obstruct the route?
Then consider the day when you cannot attend. Write down which tasks you expect someone else to do and check the instructions for any proposed equipment. This is not a substitute for crop or ventilation guidance; it is a way to discover whether the plan depends on a routine you cannot maintain.
The decision is partly about the space and partly about the job you are taking on. A larger growing area is not automatically useful if you do not want to manage it.
Compare the complete proposal
Ask for each quotation to identify the structure, chosen options, required preparation and exclusions. We do not quote prices; check current price with the supplier. Keep delivery, assembly and replacement-part questions in the same record so that they do not disappear behind the headline offer.
If one proposal remains poorly documented, pause that comparison. It is reasonable to ask for an answer in writing before committing, rather than treating an unanswered question as a benefit.
Research status
Official guidance and product-specific comparisons are still awaiting access and verification. This page therefore makes no ranked recommendation, thermal-performance comparison, lifespan claim or general statement about planning exemptions.
For the next step, take one measured growing plan and the comparison sheet to each supplier. Check the proposal with your council or allotment site where applicable before you buy.