Thursday, 23 January 2014

Is it safe to grow veggies in styrofoam boxes?....update.

In a recent post titled 'Is it safe to grow veggies in styrofoam boxes?' I asked if anyone had more information about using the boxes. Ree, from Roots and Seeds,  did leave a comment but it must have been too much for the comment box so it was lost in cyberspace. I asked Ree if she could let me know what information she had when she had time and today she has written a post on her blog titled 'Poly boxes for food growing'. So, if you have an interest in the subject then head over to Ree's blog.

Update:  Unfortunately Ree isn't blogging at the moment and her blog is not accessible so that link doesn't work any more.


There has been enormous interest in this recent post as you can tell by the list of popular posts in the sidebar.

Recently a Down to Earth forum member posted about a great book she had come across by Kirsten McCulloch from Sustainable Surburbia which could be downloaded for free as a PDF.

I had a look at Kirsten's website and the book looked very interesting so I downloaded it onto my very new iPad and, not knowing how to use the new little bit of technology, promptly lost the book and wondered where on earth it had gone to. I now know how to save a PDF if any of my former work colleagues are reading this as the iPad was a retirement gift and they were helping me to get my brain around how to actually use it.

When you download the PDF Kirsten follows up with regular emails and offers of some very helpful tips and printables which are always much appreciated. So I emailed her and asked if she had any information about how safe it is to grow vegetables in styrofoam boxes and she very kindly did some research and has given me permission to share her reply email and here is the relevant part:

Proceed with caution.

Most people now know that Styrofoam hot food and drink containers can leach styrene which is classified as a "reasonably anticipated to be a human carcinogen".  There is also some evidence that styrene can leach into cold water, as indicated in these two papers, though, it certainly appears to be far less of an issue in cold water than in heated or fatty substances (source).
Polystyrene does also off-gas, however this is an issue mostly for the people working with it in factories, not for those with a few boxes on their balcony.

So overall, I think they are probably safe to grow your seedlings in, though I would personally avoid growing direct use vegetables (like salad greens) that will spend their whole lives there.  Also, keep in mind that:

  • Styrofoam is not good for the environment, takes a very long time to breakdown, and can be attractive to birds and animals to eat, so I would only ever use it as a "reuse" option - better reused than dumped in landfill, but I wouldn't buy it new.
  • And, UV light will eventually cause the box to break down into those little styrofoam beads, and once that happens, you do want it out of your garden, and away from wildlife. However, I know of people who have been using the same boxes for a few years.

Styrofoam can be recycled, but it is often not economically viable to do so, so not all recycling centres accept it, however some do, so check with yours. It's recycling code is 6.

I hope that was helpful.

Many thanks to both Ree and Kirsten for sharing that information. I am sure it will be read with great interest by a lot of readers. Now, of course, it is up to each individual to make up their own mind about whether or not to use the boxes. 


  1. Good information again, and I will go check out her blog.
    Thank you!

  2. Thanks Nanna Chel, I found Kirsten's E-book some time ago and have found it very interesting although I have not read it all. It's making me think twice about the styrofoam though :)

    1. We have decided not to use them Tanya. We have plenty of other options fortunately.

  3. I am just about to plant some transitional vegies into these boxes until the weather cools down enough to plant up the vegie garden. Food for thought (no pun intended) so I'd better review both the book and the website. Thanks Chel, for raising this one again.

  4. Thank you so much for getting that extra information I wont be using them after reading all the risks. I have ordered another water savers garden & have some big pots I got for free that I will put herbs etc in.

  5. Thanks for researching this Nanna Chel. I've got herbs growing in styrofoam boxes out back (no garden in this rental property) so we're off next weekend to purchase proper planters for future harvests.

  6. It is debatable whether they are okay to use or not as you would have read, Jenny. However, my hubby would prefer to err on the side of caution.

  7. I have been using styrofoam boxes to plant veggies for many years and only recently I heard about it is not good for health. I am puzzled coz if they are not safe why are they being used to contain veggies moving from places to places.


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