How to choose the best greenhouse?

A greenhouse is an essential investment for any enthusiastic gardener. It’s perfect for sowing seeds, taking cuttings, growing delicate plants and crops, and protecting tender varieties through the winter months.

There’s a wide variety of greenhouses available on the market, with prices ranging from a few hundred to several thousand dollars. The model you choose will largely depend on two factors: the space you have available and your budget.

Before doing anything else, it’s important to decide on the location, as this will determine the size and style of greenhouse you can install. You’ll also need to consider whether you’re comfortable building it yourself — including laying the foundation — or if you’ll need professional installation.

Below, you’ll find a buyer’s guide explaining how to choose a greenhouse and what to look for when purchasing one.

How to Choose a Greenhouse

Size

Greenhouses come in a range of widths and lengths, usually in 2 ft (60 cm) increments. For comfortable movement inside, aim for a greenhouse that’s at least 6 ft (1.8 m) wide. A width of 8 ft (2.4 m) allows for shelving (known as staging) on both sides.

The eaves — the part where the roof meets the walls — should be at least 5 ft (1.5 m) tall to allow plenty of natural light. Most gardeners later wish they had gone bigger, so choose the largest size your budget and space allow.

Shape

There are three main greenhouse shapes: traditional, lean-to, and round (with newer options like domes becoming popular).

• Traditional greenhouses are freestanding structures with full glazing.

• Lean-to greenhouses are built against a wall — ideally a south-facing one — such as a house or garage wall. The wall retains heat from the sun, especially overnight, creating an ideal environment for plant growth.

• Round or dome greenhouses are great for awkward or limited spaces and can offer superior airflow.

Material: Timber or Metal?

Aluminium greenhouses are affordable, lightweight, and low-maintenance. They can also be powder-coated in a variety of colors.

Timber greenhouses, usually made from cedar, are more attractive and better at maintaining a stable temperature but require more upkeep and cost more.

Some wooden models can be fully glazed to the ground, while others have half walls made of brick or timber, which help retain heat but reduce planting space at ground level.

Glazing Options

The type of glazing you choose affects light levels, safety, and insulation:

• Horticultural glass: Offers maximum light transmission, is durable, and easy to replace.

• Toughened glass: Safer and stronger — ideal for family gardens or high-traffic areas — as it shatters into small, less dangerous pieces.

• Polycarbonate panels: Lightweight, inexpensive, and excellent for insulation, though they allow slightly less light through and can sometimes pop out in strong winds.

• Fiberglass panels for greenhouse: As offered by Stabilit America, these are a premium alternative, providing excellent insulation, impact resistance, and long-term clarity without yellowing.

Ventilation

Proper ventilation is essential, especially in summer. A standard 6 ft x 8 ft (1.8 m x 2.4 m) greenhouse should have at least two roof vents and a side vent for adequate airflow.

It’s worth investing in automatic vent openers, which adjust the vents based on temperature — saving you the trouble of manual control.

Flooring

A solid, level floor ensures safety and good drainage. Common options include:

• Paving slabs or gravel over a compacted base of hardcore and sand — easy to clean and maintain.

• Soil borders, which are excellent for planting greenhouse crops directly into the ground.

During the summer, the floor can be damped down with a hose or watering can to increase humidity levels and keep the air moist — ideal for healthy plant growth.

Once you’ve chosen your greenhouse, you’ll want to equip it properly. Explore essential tools and accessories — such as thermometers, shelving, and automatic watering systems — to make the most of your space. And if you’re seeking extra storage instead of growing room, a garden shed might be the better choice.