DIY Greenhouse: How To Build A Simple Greenhouse

A DIY greenhouse takes a bit of planning, but building a greenhouse at home can be rewarding and productive.

A greenhouse lit up at night
(Image credit: terra24 / Getty Images)

Our collective interest in gardening has exploded over the past few years. For many people, food supply anxiety led to a desire to grow their own produce and many continue to do so. To extend the growing season, some of us ended up building a DIY greenhouse.

DIY greenhouse ideas may be simple and cost-effective, or more complex and costly. Before building a DIY greenhouse yourself, it’s a good idea to research various DIY greenhouse designs to get an idea of what you’re looking for and to establish a budget. Read on to learn how to build a greenhouse at home.

Considerations Before Building a DIY Greenhouse

A simple hobby greenhouse made with a polyethylene-covered framework can be put together in an afternoon. It might cost $100 or so. There are also elaborate structures that can be built that include all the bells and whistles of a grand greenhouse which might cost upwards of $6,000.

Simple structures don’t require permits but more complex greenhouses very well may. You may even have to have the local power company come out. So before you dive into a DIY greenhouse project, think carefully about what you need, what you want which may be different than need, and how much you are willing to spend.

Map out the area you wish to place your greenhouse and have all necessary paperwork in order if needed. Don’t forget to consider how you will heat the unit, get water to it, account for ventilation and humidity, and of course light the greenhouse.

Research various materials. Glass for instance, as wonderful as it is, is also very heavy so the structure to support a glass greenhouse will have to be extremely sturdy and another cost consideration. Also with some tweaking, you may be able to regulate the greenhouse environment without the use of automatic controls which can be a real savings.

Types of Greenhouses

Generally, the two types of greenhouses are attached and freestanding. Attached greenhouses may be a lean-to, window-mounted, or even-span. Usually, they are even-span (symmetrical roof).

  • An attached lean-to is built against a building so it is close to electricity, heat and water. It may however have limited space, light, ventilation and temperature control.
  • Attached even-span, the usual type for attached greenhouses, is similar to a freestanding structure except it is attached to the house at one end. While it is more expensive than a lean-to, it has more room and flexibility.
  • An attached window-mounted greenhouse is a small unit hung from a window wherein a few plants can be grown.
  • Freestanding greenhouses are the most expensive since they do not share the utilities of the main home. They are similar to the even-span except they’re set apart from the house to take advantage of a more sun-filled area of the landscape. It can be as large or small as desired.

Easy DIY Greenhouse Ideas

Greenhouse ideas come in all shapes and sizes from a small seed starting shelf insulated with plastic sheeting to a freestanding timber and glass structure complete with heat and automatic ventilation.

One of the easiest and cheapest DIY greenhouse structures is made from PVC piping and clear plastic sheeting. Repurposed windows and free pallets also work together to make a quick and easy DIY greenhouse.

A hoop house set atop an existing raised bed. Make the hoop house with cinder blocks and wood, and the hoop portion from heavy-duty UV plastic attached to curved PVC piping.

If you’d prefer not to build a structure, consider a cold frame, which is essentially a small, low greenhouse. Repurposed glass windows set atop a wood frame and insulated with straw bales, will give you a jump start on and extend your veggie season. No windows? Large plastic soda bottles that can be threaded on bamboo skewers can replace the salvaged windows but work in the same manner.

How to Build a Greenhouse at Home

Whether you go budget with the ideas above or all in with expensive plans drawn up by an architect, your greenhouse will essentially work the same way albeit on a more modest or grand scale.

  • Keep in mind that you will want to locate the area of your landscape with the most sun and then level that area for any greenhouse structures you build. If the greenhouse is used more for summer plant propagation rather than for early seed starting or extended crops, choose an area of partial shade. If you do not have a partially shaded site, a shade cloth or white plastic covering can reduce the solar load on the greenhouse.
  • Also, pay attention to airflow around the structure. Avoid low areas. Easy access to power and running water is imperative.
  • Determine what size greenhouse will best fit your needs. Decide on a frame and covering; glass, PVC, vinyl, polyethylene, acrylic. Decide how you will heat, cool, and ventilate the structure.
  • Consider that you can physically do yourself. Will you need additional help? Will that be in the form of hired labor or friends and family?
  • Invest in the time you need to make decisions regarding your greenhouse, a money and time saver down the road.

Frequently Asked Questions

What Is the Cheapest Way to Build a Greenhouse?

Greenhouses, even DIY greenhouses, can be expensive. The most cost-effective way to construct your own is to source or repurpose used windows, wood, pallets, and other materials. Also, make sure your structure is in full sun to take advantage of the light and heat.

Can You Use Plexiglass for a Greenhouse?

Yes, plexiglass (acrylic) can be used in the construction of a greenhouse. The standard weight used is 3mm.

Amy Grant

Amy Grant has been gardening for 30 years and writing for 15. A professional chef and caterer, Amy's area of expertise is culinary gardening.