Getting stuck choosing the best greenhouse? There are many factors to consider, and a variety of options available when it comes to greenhouse setup and design. In this post, I’ll break down and explain some key elements to keep in mind when browsing for your first greenhouse.

One of the first considerations is size. Before taking the plunge on a particular model, you’ll want to have your greenhouse site in mind. Pick an open spot with full access to sun. Generally speaking, a greenhouse with a retractable roof is ideal, which will allow more flexibility and expansion in the future. Even if you simply want a spot for starting your seedlings, you’ll still find that having an extra 10 or 20 square feet will give you more breathing room and workspace, and it might encourage you to expand to a new gardening territory.

Greenhouse glazing material

The glazing material is another important consideration. The glazing type will affect a range of properties, most notably the R-Value, lifespan, cost, and weight.

Polycarbonate

Polycarbonate is very hard and strong. It generally has a lifespan of 10-15 years, after which time it may start to yellow. In the double or triple wall varieties, it has very good insulation and light diffusion.

Glass

Glass has a wide range of properties, but generally speaking, it is the heaviest of greenhouse glazing. Glass can potentially last forever with proper maintenance, and it is recyclable. It may be harder to install than other materials and doesn’t have the same light diffusing properties of the plastic based coverings, but it is scratch resistant, fire resistant, doesn’t expand and contract, and it has a classic aesthetic.

Acrylic

Acrylic is fairly similar to polycarbonate, but with a few slight differences. It gets slightly more brittle when it ages– either due to fluctuations in the temperature or from being struck, but acrylic is clearer than polycarbonate and has better light diffusion, and it also won’t yellow over time. Acrylic has a lifespan of 10-20 years.

Polyethylene

Polyethylene comes in two varieties: film and rigid panels. Poly film is good for simple or temporary structures, or for those working within a tight budget, and tends to last 1-5 years. Ridged polyethylene is softer than acrylic and polycarbonate, and can be rolled up when transported. It’s cloudier than the other plastics, and has a white appearance rather than clear–which can lead to a slightly cooler greenhouse. Polyethylene still maintains good R-Value and longevity, lasting 10-20+ years.

Environmental control

Environmental control is another factor to take into account before deciding on your greenhouse setup. Airflow and ventilation are important for greenhouses of any size, as temperatures can get hot in an enclosed space– it’s a good idea to have a glass and glazing shop drawing expert design the ventilation system of your greenhouse and pick something that will be easy for you to maintain. Fans may be needed for circulation and to help plants develop strong stems, and a shade cloth might be necessary for certain partial-sun plants.

We hope this guide steers you in the right direction! Check back every month for articles helpful to both future, current and seasoned greenhouse owners.

Next month: basic greenhouse management and tips for new greenhouse owners.