A Growing Concern
May 2, 2011 8:00 AM   Subscribe

Container garden: Plastic storage bins... is the plastic safe for food?

I'm planning a container vegetable garden on the side of our house. I would like to use large plastic storage bins - rectangular type you might buy at Target - as the containers. I know there are types of plastics that are not fit for storing food (and growing food?) ... but I don't know much about plastic or the designations... etc.

Anyone know if I can safely use these bins?
posted by ecorrocio to Home & Garden (8 answers total) 3 users marked this as a favorite
I can't speak to the food safety aspect but I've used the same kind of storage boxes to grow non-edible bog plants. They really don't hold up to continued exposure to sunlight and heat: the clear hard kind get brittle and crack into shards within the year when left outside, the opaque 'soft' kind get saggy and split along the sides.
posted by jamaro at 8:28 AM on May 2, 2011

Can't speak to food safety either. I do grow herbs in a plastic window box, and I'm sure that most of the produce I eat is produced in some way that is gradually giving me cancer, whether in a plastic box or in heavy-metal-laced dirt or sitting in plastic bags in the grocery store...

In any case, some alternatives...

First, I would avoid metal containers (no matter how cute a red-flyer wagon might be) because they rust and you don't want to eat that.

Lifehacker recently featured a wooden pallet garden.

You could easily make wooden boxes.

i often see attractive wooden and cement barrels and cylinders in gardens. I imagine they come from your local garden center.

You might get better answers if you explain why you want to use containers - because you don't have earth to dig in? because you want to be mobile? because it's an experiment?
posted by jander03 at 8:45 AM on May 2, 2011

Response by poster: I'd like to use the containers because:

a. not a lot of digging space, and I like the idea of raised containers - will have two rows, with the back row elevated
b. storage containers seem like are, cheap, quick and easy for this purpose
posted by ecorrocio at 9:02 AM on May 2, 2011

The commercially-available plastic growboxes appear to be made from PP #5, a food-safe plastic. I believe the "problem plastics" are #3, 6, 7.
posted by chazlarson at 9:16 AM on May 2, 2011

Food safe plastics have more to do with mold release agents and other stuff that gets added to the mix than actual chemical type of plastics. There are lots of food safe plastics. Plastic storage bins from target are most definately NOT food safe. However your chances of significant contimation getting taken up by plants are pretty slim. If you are determined to do container gardening like this get 5 gal buckets from restaurants or the like that were made for food use. They are usually free for the asking and quite durable. However your garden will always have the trashy feel to it regardless of the type of container you use.

I am not a fan of container gardening in general and especially not when the container will also have a closed bottom. To be really healthy the soil needs to be part of a large ecosystem and if it is in a container where insects, nutrients and worms cant move around freely the soil will eventually get out of balance and your plants will never really be too healthy or vigourous and the health benefits of eating fresh vegetables can be negated by this. Open bottom containers, such as wood sides, are a decent compromise but you still have problems with not being able to till your soil easily. I favor using uncontained raised beds. This just means mounding up a row of dirt and planting stuff. In the winter I smooth it all back out and till it in to get what soil rotation I can, since my yard isn't big enough to really rotate land in and out of use. This is also the time i put in compost and fertilizer so it is evenly mixed throughout the soil. I am all for growing what i can but if you don't have the room to really do it right you are better off just patronizing a local farm and growing a few items like herbs and the potted tomato yourself.
posted by bartonlong at 9:29 AM on May 2, 2011 [1 favorite]

If we are thinking of the same kinds of storage boxes (I am thinking of ones like these Sterilite containers) they are food-safe, according to Sterilite.

From the link: Our products are made of polypropylene and polyethylene that are safe for food storage. No PVCs, Latex, Teflon, Phthalates chemicals, fungicides, Bishphenol A (BPAs), or antibacterial chemicals are used in our manufacturing process.

In fact, a similar kind of storage container is used by this guy, who created the EarthTainer system (pdf) for growing a container garden. (Farhad Manjoo of Slate.com is an evangelist of the system.)

I too am concerned about how well these plastic containers will hold up in sun and heat. (Do you live somewhere very, very sunny? They'll hold up better on the Oregon Coast than in South Texas.) However, the EarthTainer guy (in the comments in the Slate article) claims that his have held up for 8 years.

And, like, you need to put drain holes in the bottoms. (You know that, right?)

An unsolicited thing to think about: This will be a more expensive process than you're thinking. Even if the containers themselves are only 10 bucks a piece, you have to fill them with potting soil. If you're doing it in, say, 31-gallon containers, you need a little more than 4 cubic feet of potting soil for each container. Potting soil comes in 2-cubic-foot bags, which cost $7 or something. If you want to do several, this could start adding up fast.
posted by purpleclover at 12:26 PM on May 2, 2011

Can't you just buy nursery cans? They're meant for plants, and if you can find them from a jobsite or a nursery that does installations you may get them free. Bonus: they last for years, and are much easier to move when full of wet soil. I grow tomatoes in 15 gallon pots from my old job- they must be 6 or 7 years old by now.
posted by oneirodynia at 5:17 PM on May 2, 2011

We now eat a lot of vegetables year round, thanks to some basic preserving -- it's had an immense influence on our diet. I'm a big fan of container gardening. I can directly control the quality of the soil and the amount of sun and water the plants receive. Diseases and pests can be isolated. The weeding is minimal at worst. Earthworms find their way into my containers just fine. I can use compost and other organic additives to keep the soil balanced. Potting soil will be your biggest expense, but it's worth it.

I use all sorts of upcycled junk and repurposed storage containers -- just check the type of plastic, and drill plenty of drainage holes. I've not had any problems with them in the sunlight.

Your new bible should be Bountiful Container.
posted by desuetude at 9:57 AM on May 3, 2011

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