by A.Redere
Considerations before planting regarding use of plastic
3:24 pm in Completed Window Farms, Education, environmental impact, Getting Started, Help the project by testing this, How-Tos, International, made from scratch (without a kit), Materials and Resources, Nutrients, Nutrition, Other Cool Urban Ag. Stuff, Plants, questions, R&D-I-Y, Seeking Advice, Starting Seeds, Uncategorized, Version 3.0 Modular Airlift Columns, Water flow by A.Redere
Hello, I discovered this website through TED, where I watched a talk by Britta Riley about window farming. As soon as I heard that window farmers have been able to grow strawberries that fruited for 9 months under low-light conditions, I was hooked. I am eager to get started on creating my own window farm.
I looked at the instructions for window farms 3.0, here, briefly. My first questions regard the use of plastic water bottles.
I did a quick search on the internet and found that plastic water bottles are typically made of Polyethylene terephthalate, commonly referred to as PETE or PET. Then, remembering hearing that plastic water bottles should not be reused, I did another quick search on what compounds are released when water is stored in plastic bottles for “too long” and what accelerates the rate of release of such compounds. The main thing I found was that dioxins are released by plastic water bottles, and doixins have been found to cause breast cancer in women, but I’m sure dioxins do not just affect women. I did another quick search on plant up-take of dioxins, and found that there is substantial literature regarding this issue as a health concern for humans. Not knowing the chemical structure of dioxins or their properties, I do not know what kinds of chemicals can be used to either chemically alter the dioxins into a safe form or to “sop up” the dioxins so plant up-take is reduced or eliminated.
My questions, then, are:
Is it safe to have plants growing in PETE bottles, with water constantly running through the bottles, extracting dioxins?
Does the design account for dioxin release? If so, how, and by what chemical/physical mechanism?
Is there a safer plastic to use than PETE, or another composition overall, for example glass?
Please do not hesitate to answer any of these questions (especially the last one) with something technically challenging (for example, using glass bottles would be difficult because cutting the glass would present a challenge). I will consider technical limitations at a later time.
Thank you!
These are all very good questions, and this is one of the main reasons why I did my windowfarm from pots that are meant to be used for gardening (www.elho.com), so I consider them safe.
A few people have used glass bottles in their farms for this reason.
I’m also wondering about the painting of these PET-bottles.
What kind of paint should you use? Not knowing anything about paint, I just have a feeling that the paint could possibly be “bad” for the PET-bottle.
I don’t think that dioxins are likely something which you should be concerned about – there may be an issue for phthalates (a chemical used in the manufacturing process of certain plastic items).
Take a look at http://www.snopes.com/medical/toxins/plasticbottles.asp if you want a bit more discussion.
As for whether plant pots or glass is better – remember that glass can leach substances as well (lead crystal leaching lead for example) and I don’t know if people even test plastic plant pots for the potential of leaching harmful substances..
Dioxin is produced when plastic is burnt.
Dario, that’s an interesting twist. I’m definitely considering.
Markus, I am unsure of that. What I would do is avoid the painting all together, and purchase ‘containers’ that are dark ‘by nature.’ For example, a ceramic pot, as mentioned previously.
Martin, thank you for your input. I will be reading your link shortly.
Thank you to everyone for sharing!
This is a very good topic. Maybe it has come up before, and I just haven’t gotten to it yet
So I was thinking glass with some basket system, instead of trying to cut holes into plastic. Here is a link for how to cut the glass (which I haven’t tried yet), and maybe a cork with a tube coming out of the bottle neck can guide water down to the correct place in the plant below.
http://dogsandcrafts.wordpress.com/2012/02/20/how-to-cut-glass-bottles-safely/
I shall keep looking and reading. As Hardware Junkie has pointed out, the glass has been done before. I wonder if it gets to be too heavy…
Changing your grow medium regularly should help eliminate a large percentage of these toxins.
I agree with boonie that dioxin is produced only when plastic is heated or burned otherwise it is safe to use. I forgot the link where I saw that article
From my research, I take it that HDPE (high density polyethlene) is better. holds up better under UV, which i take is the primary concern here. Not so much the amount of time water is in the plastic but that all plastic breaks down and leeches toxins under UV and we are in a high UV environment considering we are growing plants in the plastic. I use HDPE or covered PEX (stuff used in potable water piping) or covered PP for my aroponics, so water is not sitting in the PP.
I would not be concerned at all as long as you isolate the bootle from light (ex: old cloth) and heat (ex: recycled stirfoam between cloth and bottle). IT is an excellent opportunity for old plastic bottle recycling, as most of its chemical gases been released when it was first used. good luck
If using plastic concerns you, then just go with glass. I made a 2-column window farm and also got concerned after a while about the use of plastic. I’ve taken it down and am going to experiment with wine bottles. If I get it done anytime soon I’ll send you a pic. I just tried to google an image of what I’ve envisioning but found nothing. Also, some other concerns to consider….
1) my first window garden used the bicycle pump valves. After a few months I unhooked everything to clean it and discovered the valves had rusted. I’m not really into eating food that has been growing in rusty water. I switched to the air up-lift system.
2) Having switched to the up-lift system I decided to make a second column. At the hardware shop the man informed me that I had previously bought tubing that is not for ice makers (it said this in tiny letters on the tubing). He explained that it has a chemical in it that leaks out – thus not good for consumption. Ack! So I switched everything to landscaping tubing. It’s black and MUCH MORE rigid.
I just signed up this weekend and have the same concerns. I don’t like the idea of a plastic bottle against a hot window, heating up and leaching the water and growing materials leaching into the food I’m going so I can control what I grow. Has anyone come up with a better material or other solutions? I also want to build a movable garden table with wheels (big wheels to support the weight). I saw one at a master gardener show a few years ago and it was lined with galvanized metal which would help maintain a hydroponic environment. I am very new to this and will admit up front that I don’t even know what I don’t know at this time.
Another question, are the seeds purchased from WindowFarms Monsanto free?