Softdrink Bottle Hothouse

Intro: Softdrink Bottle Hothouse

Live in a cold area ? Sick of flimsy hot houses that blow over or are damaged in high winds ? Don't want to pay out for an expensive glass hot house? Or just want to do something to help the environment? Then this great little project is for you ! Easy to do on a small scale at home or a bigger scale at a school as well as great for educating the students.

Everybody has at home or access to soft drink bottles so why not reuse some of them and put them to good use. A very easy project to complete with little construction skills and materials needed to make it on a small scale. Essentially all you need is some bottles, something to feed them onto and some timber for a frame.

The materials I used to create our hothouse which is approximately 1600mm wide x 1900mm long x 1800mm wall height and 2100mm overall height are as follows-

1000 x 1.25L soft drink bottles - Any are fine but I found long straight ones like Pepsi are best.

80 x 1.8m x 20mm lengths of electrical conduit - I had access to lots of old dirty pieces so was lucky. You could use old off cuts joined together (which i did for some) or any other material you have on hand like cane stakes or long straight sticks.

30 (approx) x 1.8m x 90mm x 35mm length of treated pine - I used treated pine but you can use whatever timber is available in your area.

Screws or Nails to construct frame and attach conduit - I used batten screws for the frame and roof crews for the conduit.

Tools you'll need are -

- Drill

- Driver

- Saw

- Angle grinder or sharp knife

- Tape measure

- Basic hand tools

I decided to make my hothouse in panel sections which had the benefit of being able making it as I sourced materials, I could make it inside and then assemble on site and as I was doing it by myself it was much easier to handle. The downside was it needed extra materials which was some extra cost.

STEP 1: Preparing the Bottles

Step 1

The major thing you'll need to do with the bottles is cut the bottoms off ! I used an angle grinder but you can easily use a sharp knife or scissors if you're not comfortable using a grinder. I kept all the bottoms to reuse as paint containers when working with student but they could go into the recycling bin. I found the best thing was to not cut the bottom off the bottle that will be the lowest on the row when fed onto the conduit. Instead I drilled a whole in the bottom with a 22mm spade bit so it was a firm fit on the conduit. Much like the opening of the bottle.

Step 2

Remove the lid and label. I found the best thing was to use a knife and cut the label then peel it off. I wouldn't waste any time on bottles that have the label completely glued on, it's to time consuming removing all the paper and glue.

Step 3

Wash the bottles out !. It's best to wash them with soapy water and rinse with clean water to remove any old sugar deposits or foreign materials.

STEP 2: Frame

Make the frame to suit your own needs and design. The limit is really your imagination. I went with a basic shape made up of 6 individual panes and a door. I assembled the whole thing then broke it back down again to fit the bottles to the individual panels.

STEP 3: Attaching the Bottles

Next step is to feed all the bottles onto the conduit.

Firstly cut the conduit to length to suit the panel you are constructing. Drill a hole in both ends of the conduit and place a screw in the bottom hole. I started with the full bottle with the 22mm hole in the bottom and then fed as many bottles as needed onto the conduit. A lot of the time you will need to alter the last bottle placed on to get the correct gap for the top screw. Do this by cutting more off the bottom of the bottle of to suit.

Once the correct number of bottles and the correct gap is attained, lay the conduit (with bottles) onto the frame and attach the two screws to the frame.

You can see in the photo's the correct orientation of the bottles to allow water to run away.

STEP 4: Construction of the Panels

Once all the panels are done you can move them to the site of your hothouse and reassemble the frame. It's probably best if you have someone that can help you with this step as it's a bit tricky by yourself !

STEP 5: Growing

Lastly it's time to plant up !

As my hothouse was replacing an old green house I cut down and altered the steel stand so I could reuse it in the new hothouse. I also fitted a spray self watering system to the roof so everything is watered once a day in spring/summer.

STEP 6: Final Word

This project was a great way of incorporating recycling into a school garden program. We were able to reuse soft drink bottles, old electrical conduit that was unable to be used and an old greenhouse stand. The students were amazed that things which were useless by themselves could be re purposed into something very functional, which we now grow all our seedling in.

While not as efficient as a glass or a fully enclosed hothouse the bottle hothouse is on average 4 degrees hotter than the outside temperature. All our seedlings have survived and thrived when they have been planted out. I believe the plants are hardier than plants grown in enclosed hothouses as they have some exposure to the outside conditions without being effected by wind, frost of glaring sunlight.

I'm trying to grow banana's in it now !

Have a go at one yourself and let me know what you think of it ! I'd love to know what other people think and I'm happy to answer any questions people may have.

Cheers

Comments

[raphaelle]

Merci infiniment pour le partage de vos projets et de votre site très riche en informations et savoir faire

[GilbertD6]

Realistically I don’t see his family keeping this project maybe 12 years let alone 450 years. This dirt ball has been here 4.6 billion years and we as a species about 300,000? We’re just a flash in the pan. Enjoy life.

[Rainbow Cherry]

Um btw, plastic needs to biodegrade for 450 years as seen below, but greenhouse gas is worst, so aren't you generating more gas by doing this? When sunlight passes though plastic it will generate Co2 and that is one of the most severe greenhouse gas. Well just giving an opinion, maybe you could change it a bit, not with glass bottles, no, but since you are noticed that we need to help the environment, why cant you change it a bit?

[Stephen24au]

I’m in Southern Australia where our temperatures range from -3C (27F) and frosts in spring to 42C (108F) and bushfires in summer ! The gaps in the bottles allow for a nice bit of airflow in the summer months. Thanks to everyone that has added comments so far !

[shalnachywyt]

I hope you're not being affected by the recent batch of brush fires.

[Stephen24au]

Not directly apart from smoke haze but I have friends who are being evacuated today ahead of a 40 degree day and strong winds tomorrow. The whole country is burning at the moment you just never know where the next fire will start !

[shelbeeray]

These fires are terrifying. We went through fires in 2017 (I live in British Colimbia). Stay safe! I'm actually thinking of trying this, a bit modified, for around my compost pile. I live in an area that's a bit over 3,000 feet above sea level. Stay safe!

[shalnachywyt]

Apparently it takes about 450 years before the plastic bottles will degrade. Instead of poking a hole through the bottles to stack them, I think somehow being able to stack the bottles on the north and possibly west side of the greenhouse on top of each other and fill them with a dark liquid would assist in keeping the greenhouse warm in areas where there are very cold winters. You've given me an idea and I'll try to come up with a plan. (Like I need more projects! ::smile::)

Also, make sure that the wood touching the ground is treated wood, although even treated wood will rot after a while. Personally I use composite lumber for the pieces that touch the ground since that doesn't rot at all. Little more expensive but cheaper than having to replace rotted wood every ten years or so.

[Dannlh]

You'd be surprised how quickly the UV from the sun will degrade the bottles, and most plastics for that matter.

[Stephen24au]

Ours is 2 years old and shows no sign of degradation. Even if it does it will be a great learning experience for the students at the school.
I think mild and mildew collecting in the bottles might be my biggest problem 🤔

[shalnachywyt]

Yeah, that's what I was thinking as well, but when I searched for "how long before plastic degrades" I got "450 years" or so, which surprised me. That's why I'm hesitant to build something like this. Frankly I have a lot of old swimming pool liners lining the walkways between my raised garden beds and they've lasted almost 10 years, much to my surprise.

[SeanB10]

The low integration also make the end product easy to recycle.

[LDW01]

We, Local primary school and parents, built one of these in 2010 April. It is still in use and very popular with everyone

[Stephen24au]

That’s awesome ! Ours is 2 years old and shows no signs of degradation

[Davilyn2]

You just gave me a great idea. My brother drinks a lot of bottled water. I currently take the bottles to the recycler. If I painted the bottles dark blue (not a fan of black) and filled them with water, I can make a really great Trombe Greenhouse. Thanks for being the inspiration.

[shalnachywyt]

I've tried doing that with other pieces of plastic and the paint just peels off in the sun. I'd fill the bottles with water dyed with acrylic paint, which seems to work better.

[Davilyn2]

Are you using Krylon "made for plastic" spray paint? I use that all the time to paint clear storage bins for my hydroponic systems and it has been just fine. The Krylon made for plastic paint also has primer in it along with the paint.

The paint inside the bottle would probably work fine most places but I live in the desert and it would probably turn clear inside by the end of the summer. I will do a test this summer and see what works best. Maybe used cooking oil might be better than water. Would hold heat longer.

[shalnachywyt]

No, I was not using Krylon made for plastic paint. Maybe that was the problem. On the other hand, the idea of using "used" cooking oil instead of water is a great idea! Thanks.!

[charlessenf-gm]

"on average 4 degrees hotter"
Hmmm, I was thinking about our Winters where temps drop below freezing.
Also thought that the PVC could pass through the 2 by material - thus centering the bottles within the walls allowing, thus, for covering the exterior walls with plastic sheeting (and even the interior side) to create more insulation and heat gain. Leaving the eaves (Triangular portion) just the bottles for air flow.
Note that, if the PVC were left intact (no holes drilled into them) they could (be painted black and) contain anti-freeze protected water solution which would help heat retention over night.

[Davilyn2]

I think the fact that he cut the bottles lowered his heat gain to almost nothing. I live in the desert and have 12mil greenhouse plastic up and on a 40 degree sunny day in the winter, the inside is 80 and that is just plastic. But I am looking for something that would help it at night. Currently I have Christmas LED lights in there, looped on the plants and that has worked pretty well.

Someone else said she puts acrylic paint and water inside the bottles. But I think I will experiment with used cooking oil - that would hold heat longer than water. But yes, greenhouse plastic (not the stuff from Home Depot or Walmart), then the bottle uncut and filled with water or oil inside would give you a pretty good Trombe wall.