Benefits of Having a Greenhouse
A greenhouse extends the growing season so you can start growing plants earlier and for longer. A greenhouse from recycled windows is a great space to start seedlings, take shelter from the rain, provides options water capture and doubles up as a place for storage.
Our Garden Match Game Cards available from our homepage include a Greenhouse as beneficial infrastructure as well as garden vegetables, herbs, animals and insects.
Comparison Cost of Commercial Greenhouses
The greenhouse we built shown below is approx 4m x 3m (13ft x 10ft) and most of the materials we were able to source for free. We found a similar sized wooden greenhouse available at a popular UK garden supplier for £5000, while aluminium or composite greenhouses are available for less at around £1000.
How to Build a Greenhouse from Recycled Windows
1. Collect Old Windows
Window installers generally throw out old windows that they are replacing. Call local window suppliers and ask them if they can make old windows available. We were lucky and collected around 40 wood frame windows for free, though it took some time (a good number of weeks) and was quite a lot of work transporting them on a car roof rack.
2. Making a Greenhouse Plan
Make a plan based on the windows you have to calculate greenhouse size and window placement. Once you have a good number of windows, measure each and arrange to make up the 4 walls of the greenhouse. You could do this by creating scaled cut outs and rearranging them on a table, or in graphics software, or ask ai to make the plan.
3. Orientation and Placement
Depending on space available and your garden layout, the greenhouse should be situated in a place where it receives the most sunlight, in the UK this usually means aligning the longest side east to west for consistent light during the day. Also avoid windy spots, flood prone areas, make it accessible, use a flat area (though greenhouses can also be designed on slopes).
4. Prepare the Plot
Clear the area where you wish to build your greenhouse.
5. Foundation and Ring Beam
Commonly used to tie the walls together, prevent settlement, and resist lateral forces, the ring beam serves as a base for wall construction. We made ours from concrete blocks and 4×4 wood beams. The space between the concrete blocks we filled with clay and allowed to harden.
6. Add Windows & Timber Studs
Place window on the ring beam, add a timber stud (approx 2×3) to each side. Fix with screws. The stud should go up to the height of the ceiling, e.g. 2 metres. Maybe useful to screw from outside, so that if a window should need replacing afterwards, it can be removed easily. Keep adding windows around until the first storey is done. Depending on the type of windows used, more timber beams should be placed before adding the next storey.
7. Top Ring Beam & Ridge Beams
The final layer on top of the windows is another ring beam to bind the four walls together, we used 2×3’s, lighter than that used as the foundation. The roof should be pitched for rainwater collection, therefore one side needs to be slightly higher than the other.
8. Add Roof Covering
We used polycarbonate corrugated sheets with a slight pitch so that we could collect rainwater, but you may have other material available. During the first year we simply used transparent plastic sheeting.
9. Guttering & Water Capture
A greenhouse roof provides options for water capture, add guttering, a drainpipe and direct flow into a water butt, pond or other water storage which you can then use for watering plants.
The end result, a greenhouse from recycled windows, shown in our gallery maybe a little raw, so will still need to touch up before doing a final photo shoot, but remember the plants don’t mind so long as they have warmth when needed, plus we were able to get good quality old wooden windows for free.
Greenhouse from Recycled Windows Gallery
A Greenhouse from Recycled Windows:
Photo Gallery of Alternative Designs
There are a good number of articles similar to ours showing alternative designs, here are a few we think worth looking at.
Did you build a greenhouse and write about it? We would love to include a photo of your design and link to your website, please do get in touch.
Links to these greenhouses are available by clicking on the captions and listed here: a small square Greenhouse by Paul Vivier, Boutique Greenhouse at Instructables, a diy greenhouse by Sustainable Holly and a very well documented greenhouse by Harvesting Health & Happiness.