Overview of greenhouses
A greenhouse is essentially an enclosed space warmed and lit by the sun: short-wave solar radiation passes through glass or another transparent covering and heats the soil and plants inside. The short answer on choosing one: a freestanding greenhouse suits those who want a permanent structure and have the budget, a hoop (tunnel) greenhouse is the economical pick, a wall-attached greenhouse saves space and lets you use the house's utilities, and a cold frame is the cheapest way to start. Choose based on available space, budget, maintenance time, and access to water and electricity.
Which greenhouse type fits which garden?
| Type | Cost | Permanence | Best for |
|---|---|---|---|
| Freestanding | €€€ | Permanent | Larger plots, full climate control |
| Hoop (tunnel) | €€ | Semi-permanent | Budget-friendly seasonal growing |
| Wall-attached | €€ | Permanent | Small gardens, shared utilities |
| Cold frame | € | Portable | First projects, season extension |
1. Freestanding greenhouse
A freestanding greenhouse can be placed anywhere on the plot.
The model most people imagine: a wood or metal frame covered with glass or translucent polycarbonate. Kits range from small hobby sizes (about 2×4 m) to industrial-scale structures with heating and ventilation. Suitable if you want a permanent greenhouse and the budget covers construction — especially if you plan a foundation plus ventilation, lighting, water and electricity.
Pros: even light distribution, few shadow problems, any size. Cons: labour-intensive to build and less energy-efficient than wall-attached models — more exposed wall area radiates heat away.
2. Hoop (tunnel) greenhouse
A hoop greenhouse built from arches.
A less permanent, more affordable option covered with plastic sheeting. Easier to build, simple to adapt to the dimensions you need, and available as kits. Tunnel greenhouses usually rely on passive heating, cooling and humidity regulation, and plants are often grown directly in the existing soil rather than raised beds.
Pros: the best price-to-area ratio, quick to erect. Cons: limited climate control and a shorter covering lifespan than glass or polycarbonate.
3. Wall-attached greenhouse
A wall-attached greenhouse facing south.
Designed so at least one side connects to an existing building — ideally a south-facing wall. Size is set by the wall it leans on, so these are usually smaller than freestanding models and can be shaded by the adjacent building.
Pros: ideal for limited space, and the building's electricity and water can serve the greenhouse — the most economical utilities setup. Cons: less room for crops and possible shading.
4. Cold frame
A wooden cold frame with an opening lid.
Not a standard greenhouse, but an excellent first project: a glass or plastic cover that protects seeds, seedlings and plants from cold, wind, snow and rain, extending the growing season. Cold frames can be semi-permanent or portable, moved around the garden as needed.
Pros: the simplest and cheapest way to explore greenhouse growing. Cons: very limited space and no standing-height access.
How do you choose the right one?
Think through location, size and structure type against your space, budget and growing needs. A freestanding greenhouse is the versatile choice for a large, permanent setup; a tunnel greenhouse is the economical option; a wall-attached model suits small spaces and shared utilities; and a cold frame is a great starter to extend the season. Whichever you choose, plan watering early — consistent soil moisture matters more to yields than the covering material, and an automatic system like the GRAAS iRigator works in any of these greenhouse types, including off-grid tunnels fed from a water tank.
Frequently Asked Questions
Which greenhouse type is the cheapest to start with?
A cold frame — it protects seedlings from cold, wind and rain for a fraction of the cost of a full structure, and can be moved around the garden.
Does the greenhouse type change how I should water?
Yes. Tunnel greenhouses growing in native soil dry out differently than raised beds, and wall-attached models often have drier zones near the warm wall — sensor-based watering adapts to each case automatically.
Can I grow year-round in any of these?
Only a freestanding or wall-attached greenhouse with heating and lighting realistically supports year-round growing; tunnels and cold frames are season extenders.