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      Frequently asked questions

      What is a tunnel greenhouse?

      A tunnel greenhouse is a covered growing structure with a curved frame and a protective polyethylene cover. It helps create a warmer, more sheltered environment for growing vegetables, seedlings, herbs, and flowers.

      Is a poly tunnel the same as a tunnel greenhouse?

      Yes, in most cases they refer to the same type of structure. “Poly tunnel” highlights the polyethylene cover, while “tunnel greenhouse” describes the overall greenhouse shape and use.

      What can I grow in a grow tunnel?

      You can use a grow tunnel for vegetables, herbs, seedlings, leafy greens, strawberries, and many seasonal crops. It is especially useful for plants that benefit from extra warmth and protection from wind and rain.

      Are tunnel greenhouses good for New Zealand weather?

      Tunnel greenhouses can work well in New Zealand because they help protect plants from changing weather conditions. Choosing the right size, position, and anchoring method is important for better long-term performance.

      Why choose a tunnel greenhouse instead of a rigid-frame greenhouse?

      Tunnel greenhouses are often chosen for their value, simple structure, and large usable growing area. They are a practical option for gardeners who want more covered space without stepping up to a more premium greenhouse style.

      Do tunnel greenhouses need ventilation?

      Yes. Good ventilation helps reduce excess heat, humidity, and condensation inside the greenhouse. Side openings, windows, and roll-up door access all help improve airflow.

      What size tunnel greenhouse should I choose?

      That depends on how much space you have and what you want to grow. Smaller models can suit seed starting and compact backyards, while larger tunnel greenhouses are better for vegetables, taller plants, and more productive growing setups.

      Can I use a tunnel greenhouse all year round?

      Yes, many gardeners use tunnel greenhouses across multiple seasons. They are useful for extending the growing season, protecting crops in cooler months, and giving seedlings a better start earlier in the year.

      Tunnel Houses for Productive Backyard Growing

      A tunnel greenhouse, also known as a tunnel house or polytunnel, gives you a dedicated space for growing vegetables, herbs and seedlings. Its covered design helps shelter plants from rain and everyday exposure while allowing sunlight through. For home gardeners, it offers a practical way to start seedlings and extend the growing season, depending on local conditions and the crops you choose.

      Choose the Right Size for Your Garden

      Steelmates tunnel greenhouses include 3 × 2m, 4.5 × 3m, 6 × 3m and 10 × 3m options. A compact model suits smaller growing projects, while a longer tunnel provides room to organise planting beds and access paths.

      Before choosing, measure your available ground area and allow space around the structure for securing the cover and carrying out maintenance. Plan your layout so you can reach plants comfortably for watering, pruning and harvesting.

      Galvanised Frames and Replaceable PE Covers

      Our main tunnel greenhouse range combines galvanised steel frames with polyethylene covers. Selected models feature reinforced UV-resistant covers, roll-up entrances and screened ventilation windows. Compare each product’s specifications to find the access and ventilation arrangement that suits your setup.

      Matching replacement covers are also listed for several sizes, allowing you to renew a worn cover while retaining a serviceable frame. Check the model, dimensions and door configuration carefully, particularly when choosing between standard and side-opening versions.

      Ventilation and Site Preparation Matter

      Choose a sunny, sheltered position with suitable drainage. Open doors and ventilation panels as needed to help release excess heat and moisture, and check watering regularly during warm weather.

      Secure the frame and cover according to the product instructions. These lightweight structures require careful anchoring and are not intended for extreme weather or permanent building use.

      Compare Your Greenhouse Options

      Looking for a rigid-panel structure? Explore our polycarbonate greenhouses, or browse glasshouses for another growing-space option. For smaller spaces, see our mini greenhouses.