Choose Safe Containers for Growing Food
While not wanting to dampen your enthusiasm for gardening in repurposed planters, I encourage you to do your due diligence when choosing that perfect container.
Recognise this? It was once a computer terminal relegated to the scrap heap when some fancy, flat-screen newcomer came on the scene. Now, it’s been transformed by an innovative gardener into a funky planter.
The majority of pre-loved or second-hand goods will be safe to use, but before you reuse a container for planting in, here are some considerations other than whether it can hold some dirt and leafy greens!
My philosophy is “to err on the side of caution – it’s better to be safe than sorry!”
- Check the Skin it’s In! What is the container is made of? If you can, find out what material the container or item is made from (especially on the surface). Is it safe? Is the surface porous? Some materials such as terracotta are extremely porous and can absorb and leach water soluble chemicals through the surface.
- Avoid Materials contaminated with Lead or Asbestos:Lead is a naturally occurring metal but it is also a very toxic poison to all forms of life. Soil can become contaminated with lead if it comes in contact with lead based paint. Try to avoid choosing items to repurpose into a planter that may contain lead and asbestos such as old containers coated with lead based paint or building materials that may contain asbestos. Prior to 1970 paints contained high lead concentrations and prior to 1950, some paints had as much as 50% lead in them. However today the maximum recommended amount allowed in domestic paints is 0.1%. The danger with leaded paints is when the paint deteriorates (by peeling, chalking or turning into a fine dust).
The most common areas lead based paint was used in homes is on interior and exterior walls, cupboards, skirting boards, window frames and doors, gutters, fascias, metal surfaces and areas with enamel paint. If you want to reuse an item such as an old window frame, it’s important to check the age of the house it came from to make sure you avoid paint contaminated with lead.
If you are renovating or sourcing materials from a salvage shop, recycling centre or second-hand building supplier, it is wise to find out the age of the materials first. Be cautious about reusing painted materials for a garden planter if you can’t determine they’re safe – reuse them in a potting bench instead!
- Past life: Do you know the history of the item? If you are salvaging it from a farm or garage sale, has it had contact with agricultural chemicals like herbicides, fungicides and pesticides? Or has it held other toxic chemicals or dangerous substances (e.g. from medical or industrial sources, drugs or poisons)? If so, it would likely not be safe to plant into and especially not for food. Many people reuse plastic buckets as containers to grow food gardens – if they’ve come from the food industry (and are food grade plastic) this is fine but if they have come from a factory manufacturing polymers or other chemicals, perhaps it would be wise to find another planter. Pay particular attention to the recycle numbers on the plastic container – avoid plastics numbered 3, 6 and 7.
You can check whether a plastic container is safe for use in your garden by looking for the recycling symbol. It's usually on the base.
- Still not sure? You can find out more about specific materials such as terracotta, concrete and plastic in Choosing A Container – the Pros and Cons or leave a comment and I’ll try and check it out for you.
Containers suitable for use as planters are made from all sorts of materials - each with pros and cons!
No matter how appealing the container looks, please consider carefully whether it could leach residues into the soil before planting directly into it.
If you have found the perfect planter and still have concerns, here’s an easy solution:
With a little creative thinking, you may be able to still use it as a cachepot (or outer decorative container) and put your plants into another safe smaller pot inside. Nestle the plant pot down inside the cachepot or outer container and if you want to, cover the top of both containers with mulch so you can’t see the inner pot. No one will ever know!
Nestle another pot inside your perfect container if you just love the look of it but want to make sure what you grow is safe to eat!
Interested in this topic? There’ll be more specific information about the dangers lurking in our gardens in a future post so if you don’t want to miss it, subscribe to my newsletter (and grab your free eBook) or click on the RSS feed below or to the right. Want to learn more? Check out Container Gardening and Growing Your Own Food.
Copyright The Micro Gardener 2011 – http://www.themicrogardener.com
Hello!
This is such wonderful information. I am starting a container vegetable garden for the first time, I am a beginner gardener. I found some old drawers on the side of the road. They are mostly fiberboard, not real wood. Would these be safe to grow veggies in? I see lots of blogs, articles, and photos of people who’ve grown vegetables in old drawers, but my concern is that the fiberboard is treated with chemicals and/or that it could rot.
Thanks
Sarah
Hi Sarah
Thanks for your feedback on this article and glad the information is useful to help people question rather than assume, that a container is safe. Unfortunately we have to take responsibility for our own health, and even more so, when we are choosing to grow our own food organically.
Regarding your drawers, whilst I am not a trained expert in this area, I read academic and government papers regularly and try to do quality research to give me a better understanding of what some of the issues can be around certain types of materials, and at least know whether to be cautious or seriously concerned. Fibreboard (which is also known as MDF or medium-density fibreboard) would most likely fall into the ‘unsafe’ category as far as I’m concerned. From some initial research here are a few points to be aware of:
“Formaldehyde resins are commonly used to bind MDF together, and testing has consistently revealed that MDF products emit urea-formaldehyde and other volatile organic compounds that pose health risks at sufficient concentrations, for at least several months after manufacture.[4][5][6] Urea-formaldehyde is always being slowly released from the surface of MDF. When painting, it is good idea to coat the whole of the product in order to seal in the urea-formaldehyde. Wax and oil finishes may be used as finishes but they are less effective at sealing in the urea-formaldehyde.[2] – Ref: http://en.wikipedia.org/wiki/Medium-density_fibreboard
With regard to health risks:
“In all fibreboards, formaldehyde resins are used to bond together the constituent parts. This is usually urea formaldehyde, but some fibreboard including exterior or marine quality board will use stronger glues such as phenol formaldehyde. Even at a low level, exposure to formaldehyde though inhalation can cause irritation to the eyes, nose, throat and mucous membrane. Formaldehyde can also affect the skin, leading to dermatitis, and the respiratory system causing asthma and rhinitis. The International Agency for Research on Cancer (IARC), part of the World Health Organisation, quoted evidence that even short term exposure to formaldehyde, at far below the legal limit allowable in Britain, could cause irritation to the eyes, nose and throat. The IARC’s findings also stated that wood dust is a carcinogen’ (cancer causing) and that ‘formaldehyde is probably carcinogenic to humans’. IARC was also concerned about the reproductive hazards of formaldehyde’. Formaldehyde is classified in the UK and throughout Europe as a Category 3 Carcinogen. This means it is a substance which “causes concern for humans owing to possible carcinogenic effects but, in respect of which, available information is not adequate for making a satisfactory assessment.” This puts formaldehyde on the GPMU list of potential carcinogens, meaning it should be replaced where possible, and if not, subject to rigorous controls that reduce exposure to the lowest possible level.” – Ref: http://www.childrensfurniture.co.uk/mdf.html
So, without going on further, I guess you have to find out IF the drawers are made from this material, and then decide what state they are in and whether you want to keep them or use a safer alternative. It may be possible to paint them – but perhaps consider using an eco-friendly low-toxic paint! You can also refer to some of the articles on this site about repurposing containers. If you are able to satisfy yourself the drawers are not going to continue emitting toxic VOCs which could be harmful to your health, and you are really in love with this piece of furniture and still want to use it to grow food, I would still err on the side of caution and perhaps use a safe cache-pot container to grow your food and sit this inside the drawers.
I hope this helps in doing your due diligence. Feel free to ask more questions if you need to! Otherwise Sarah, I hope you enjoy learning how to grow food at home and can pick up some tips here – feel free to email any time if you need help. If you subscribe to my newsletter, you’ll get all new articles plus lots of tips and a free eBook I wrote which is designed to help beginner gardeners.
Look forward to staying in touch and would love to know how you go with your drawers!
Happy gardening, Anne
Wow! So grateful for your thorough response. So much helpful information. Very much appreciated! Excited to continue learning.
All best to you.
My pleasure Sarah. I’m working on some more posts on safe gardening so watch this space!
Cheers,
Anne
[...] Effel (that’s Steve’s spelling. Ethel is his girl and so he can spell her name however he sees fit!) Doocark has now been given 7 eggs to sit on. She has steadfastly refused to allow the fact that she has no eggs to stop her from returning to her nest each and every morning as soon as we let her out of the coop and she has to be picked up by Steve each evening and returned, protesting, to the coop at the end of the day. We have decided that the other chook who has no name and who has hidden herself away somewhere is going to most probably have some babies one day, so it’s only fair if Effel has a go as well. We have given her 7 fresh eggs to sit on. We have learned a lot about eggs. The only real thing is that they need to be somewhat fresh, and they need to be all put under the chook at the same time as that is what starts the embryo forming. We are hoping that she doesn’t get scoffed in the night because we have a soft spot for Effel. She is the only one of our chooks that is somewhat tame and who will take food from our hands. She may have been hand raised in the past. Who knows? All we know is that Effel is getting her chance to be a mum. We have 3 broodies, 4 mums, 5 regular non-broody hens and Big Yin who is fussing about them all. We have gone from complete and utter novices with anything to do with poultry to being thrown in at the deep end and forced to learn, researching sometimes late at night to find out how to sort problems out, work out what to do with broody chooks etc. It’s a real learning curve but I love researching and finding things out. I am “dead chuffed” by the way. Welcome to Annie from a most amazing blog “The Micro Gardener”. I used one of Annie’s lovely pictures in a previous post (the lovely boots full of plants) and I urge all of you to head over to Annie’s blog and have a gander. You will be stuck there for hours it’s that interesting and informative. If you are clever (I am ) you will sign up to follow her blog and you will get an amazing free e-book that is cram packed full of fantastic information. Annie, like me, loves to research things and find things out. I consider you a kindred spirit Annie and am so pleased that you have decided to follow my humble little blog. http://themicrogardener.com/choose-safe-containers-for-growing-food/ [...]
Err hopefully you put that there Annie…I have no idea how it got there if you didn’t because I most certainly didnt! Feel free to delete it if its not something that you put there
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Thanks Fran for the lovely feedback … will be watching your journey with interest! You’ve got a lot going on there. We can all learn from each other. It’s amazing how many life lessons come from our backyards!
Great information. Lucky me I came across your website by chance (stumbleupon).
I have book-marked it for later!
Hi, I’m trying to get a container herb garden going, as a sort of trial to see if I could do it then I’d add some veggies too. However, as I’m a prep cook and our restaurant goes through large cans of veggies on a regular basis, I was thinking about salvaging some of them to use for my herbs and maybe later some veggies. However, I can’t seem to find any info on if they’d be safe for food gardening! Any thoughts? Some logic would say that if they’re safe enough to can food in, they’re safe enough to grow it too, but I don’t trust it enough to buy into it fully yet! Again, any thoughts would be appreciated!
Hi Chris
Great to hear from you and a thought provoking question. My philosophy with growing food in repurposed containers is to err on the side of caution and do your due diligence. This is a HUGE topic and one I’ve had an interest in for several years. I have accumulated a lot of information on it but haven’t had the time to put together a book yet. The short answer is don’t assume canned food is safe to eat!
Here’s some recent research from an incredibly reliable source EWG who do an amazing job on behalf of consumers to find the truth and expose it on all sorts of food and personal products. Their website is a wonderful source of information and is worth a good walk around to familiarise yourself with some of the dangers associated with everyday purchases. Here’s a very brief summary of their findings:
“Independent laboratory tests found a toxic food-can lining ingredient associated with birth defects of the male and female reproductive systems in over half of 97 cans of name-brand fruit, vegetables, soda, and other commonly eaten canned goods. The study was spearheaded by the Environmental Working Group (EWG) and targeted the chemical bisphenol A (BPA), a plastic and resin ingredient used to line metal food and drink cans. There are no government safety standards limiting the amount of BPA in canned food.” There is a wealth of information on BPA out there for further reading.
Obviously metal cans rust quite quickly when they come in contact with moisture but lining them with plastic to lengthen the life of the can as a planter then brings into question how safe is the plastic? There are alternatives such as coir peat (a sustainable resource) that would act as a natural barrier but I haven’t read any findings on leaching of chemicals through a lined can. I use metal cans as planters for non-edible flowers that bring pollinators to my garden so I AM reusing them, but not for food. When their usefulness is up, then I know I’ve done my best to repurpose the material and not just add to landfill.
More research on this topic is definitely needed. If you find any answers or reports that help shed light please feel free to share them here to inform others. I will also update this website as I find out anything new. Hope this helps somewhat!
I purchased containers in the US but were made in Canada. The bottom of the planters say D81614. Wondering if these are safe for gardening vegetables. Thank you.
Hi Beverly
I can’t say for sure as I’m not familiar with that numbering system. Perhaps you could start with the retail outlet and ask if they can provide you with the supplier or manufacturer’s name. Once you have that, you can ask for specifics. If I have any concerns about a material or have not been able to ascertain the history/source, I add zeolite to the potting mix or garden bed. Zeolite is a natural mineral that helps bind toxins and contaminants in the soil. Hope this helps!
Hi Anne,
I’m looking at repurposing an old Weber BBQ as a mobile herb pot. It was only after i painted the weber that I now worry whether it will be unsafe to use for veggies or herbs – because of the paint. Would you know whether spray paint would be toxic to grow things in? Thank you
Hi Kate
Thanks for your inquiry and great to hear you are repurposing a Weber BBQ! A mobile herb pot is a fantastic idea. I can’t really comment on your particular situation in terms of the kind of paint you’ve used. If you are worried it is chemical based, then perhaps you could contact the manufacturer and explain the application you are wanting to use it for and ask if they can provide you with a MSDS (Material Safety Data Sheet) on their product. If you think it could potentially leach chemicals into the soil, then I’d suggest a) either giving it a coat of non-toxic paint over the top of what you’ve already done b) adding zeolite (a natural mineral you can buy in small quantities from produce stores) to the soil. It helps bind toxic substances and make them inert so this could be an ‘insurance policy’ of sorts! Hope this helps. Please feel free to share your pic on The Micro Gardener Facebook Page or email me if you’re happy to, when you’re done. I’m sure your project would inspire others. Hope this helps.
Thanks so much for the great advice, Anne! Will send a pic through when it’s done.
Hi Anne, I found 24″ Fiskers plastic, clay colored pots in a big box store. The only numberon the bottom is 24, assume that it refers to the diameter. How do I know if these are safe for growing edibles? I’ve checked the Fiskers website and cannot find any info. Thanks for giving me peace of mind.
Lynn
Lynn I’d suggest contacting Fiskers direct and checking with them about the product you have. They may be able to supply an MSDS (Material Data Safety Sheet) or at least advise which plastic recycle number it is. I recommend avoiding 3, 6 and 7. Perhaps ask the question via https://www.facebook.com/fiskars? Hope this helps.
[...] particularly if you’re trying to grow organic produce! So how do you know if it’s safe? The Micro Gardener (who has done quite a bit of research on this topic) recommends you steer clear of plastics 3, 6, [...]
[...] one. A mini in-situ worm farm I use is the Little Rotter – it’s compact, made from a safe plastic and adds humus where you need it (directly in your [...]
Hi Anne, and thank you for the great page! I am thinking of using an old trunk that’s bottom is a bit worn down from getting wet. There is fabric on the inner walls I may pull out. Could I line this with anything to make sure it is safe to grow herbs in? thanks so much for your wisdom!
Happy growing!
-Katie
Hi Katie
Thanks for stopping by. Firstly I’d suggest adding drainage holes in the base so your plants don’t become waterlogged. You don’t mention what the trunk is made of – metal? synthetic? If you know, you could do some research on the type of material to find out if it’s likely to leach any chemicals and whether it’s an issue or not. You may also want to block the moisture from rotting the trunk if water will degrade it. If so, line with something like weed mat you can cut to size which will add a less permeable layer inside but still have drainage on the bottom. Or if you want to preserve the trunk for much longer, why not source another smaller container you DO know is safe to plant into and sit this inside? Then use the trunk as a decorative outer cachepot. I also add zeolite (a natural rock mineral) to the potting soil mix to absorb any toxins that may leach into the growing medium. Zeolite binds the toxic chemicals and renders them inert. It’s kind of a natural insurance policy. Hope this gives you some options to consider.
Hi, I bought some old popcorn tins at a garage sale and I am planning on lining them w tree bark paper before I put my vegetable plants in them. I know they will probably rust, but I figure they are a one season use anyway. Wondering what popcorn tins are made out of and what chemicals might leach into my plants if I use them? I did a google search and found that tins are either aluminum or steel w aluminum paint… Are these safe to plant in? Thanks for your time
Whoops! I meant steel covered w tin paint, not aluminum
Hi Tina
I’m not familiar with popcorn tins but found a company that makes them @ http://www.ballsteeltinusa.com/our-products/popcorn-tins/ – perhaps if this is the style of tin you have purchased, you could contact the company directly to learn more or ask for a MSDS (Material Data Safety Sheet).
If the metal is stainless steel, it’s worth knowing that it can leach some heavy metals according to research I’ve done. You can read more in the article ‘Stainless Steel Leaching into Food & Beverages‘. Whilst this information doesn’t specifically relate to growing food in stainless steel, one can reasonably conclude that if it leaches heavy metals like nickel, chromium and iron into food, this could also occur in soil. So I guess it’s a matter of applying the ‘precautionary principle’ and erring on the side of safety rather than risk. If I’m unsure about whether there could potentially be toxic substances in my soil or a container, I add zeolite, a natural mineral that helps absorb heavy metals and prevents them from leaching into the environment – a kind of ‘insurance policy’.
You may also find a comprehensive Review of Stainless Steel Toxicity of interest. It’s my opinion to balance repurposing materials as planters with avoiding unnecessary health risks. You can always use the tins for flowers or other ornamentals rather than food and consider some other materials that are low cost to repurpose. There are plenty of ideas on this site. Hope this helps!