Instructions for a Walk-In Greenhouse

Metal greenhouse in summer with open door image by Scott Latham from

A walk-in greenhouse is a structure that allows you to create a controlled setting for your plants to grow. Before moving forward on the project, take time to do the proper planning and preparation. Decide on a greenhouse design that meets your needs and fits into the space you have allotted.

There are a variety of portable or temporary models or full-size permanent structures that can be built from greenhouse kits. If you have the technical acumen, you can elect to build your own walk-in greenhouse.


Regardless of the model or size of your walk-in greenhouse, position the structure in a location where it can get the maximum amount of concentrated sunlight. The southeast side of your residence or a spot where there are shade trees is typically the best site. Another option is the eastern side, which permits for a longer growing season. Try to locate the structure away from trees that retain their foliage year round, which blocks the winter sun. Take into consideration water runoffs and drainage patterns. There must be adequate drainage of rainwater from the site.

Greenhouse Kits

Walk-in greenhouses come in many shapes and sizes. One of the most common structures is a rectangular-shaped building with a gable-style roof. Both equal-size sections of the roof slope downward on top of the side walls. The kits are comprised of extruded aluminium framing components that must be assembled. Usually, a galvanised steel base is available as an option. The wall and roof panels are made of UV-protected polycarbonate panels. The units can be ventilated through a window in the roof structure and/or windows in the wall sections.

The hoop model is also a popular choice for greenhouses. Typically, PVC or pipe is used for the framing. The skeleton of the structure is then enclosed with polyethylene.The fastening methods vary from product to product. The plastic sheeting does require periodic replacement.

Build Your Own

Build a walk-in greenhouse from scratch using 4 inch by 4 inch timbers as the base. Frame the wall sections out of 2 inch by 4 inch lumbers. The lumber must be redwood cedar or some other pressure-treated wood. Build the rough openings for the windows and door. Although you can build the roof structure from separate components, the most common technique is to install roof trusses.

Cover the roof and the walls with UV-resistant polythene secured with 1 1/2-inch wood strips, which are called battens. You can also choose to mount polycarbonate panel for the walls and roof. Install the door and windows.

Other Features

Decide on grow lights, humidification and cooling systems for the walk-in greenhouse. Decide the placement of benches, baskets and shelving for the various types of trousers. Plan the water and electricity for the greenhouse. Some people use a system of gutters and downspout for an environmentally-friendly greenhouse irrigation system. A heat source may be required if you plan to work year round.