An important consideration for container gardening is knowing which plant pots and containers are non-toxic and food safe. Not all plastics are rated safe for food. This guide will present you some safe selections to use for your garden.
If you have looked at the pros and cons of plastic containers and have decided to go with them, it only makes sense to make sure that you select containers that are safe.
Unfortunately, and unlike food ingredients that must be printed on the label, plastic containers do not have to have a list of their ingredients. So how do you know when it container is safe and non-toxic?
Perhaps the safest and most current conservative approach is to look for products that have been rated “food safe”. If the ingredients of the plastics are not listed how do we know whether a product is food safe?
We have the recycling industry to thank for help in that area. With the move to recycled plastics, they are generally marked now on the bottom with a “resin identification code”. This is a number within a triangle that shows workers at the recycling plant what the court ingredients are.
Plant pots from the nursery can be made with HDPE (2) and PP (5) .
You Can Use These – non-toxic food safe plastic containers will be marked numbers 1, 2, 4, 5 .
Don’t Use These: containers marked numbers 3, 6, 7.
- “1” signifies polyethylene terephthalate (PET) (beverage bottles, cups, other packaging, etc.)
- “2” signifies high-density polyethylene (HDPE) (bottles, cups, milk jugs, 5 gallon buckets.)
- “3” signifies polyvinyl chloride (PVC) (pipes, siding, flooring, etc.)
- “4” signifies low-density polyethylene (LDPE) (plastic bags, six-pack rings, tubing, etc.)
- “5” signifies polypropylene (PP) (auto parts, industrial fibres, food containers, etc.)
- “6” signifies polystyrene (PS) (plastic utensils, Styrofoam, cafeteria trays, etc.)
- “7” signifies other plastics, such as acrylic, nylon, polycarbonate and polylactic acid (PLA).
In all fairness, I must reveal I am not a plastics engineer. But, I have done a lot of research for degrees, papers, and articles. I looked for authoritative sources in order to substantiate the information I’ve giving you. Resources such as United States Department of Agriculture USDA, National Geographic’s “Smart Plastics Guide”, Wikipedia and others.
Take a look at this four minute video showing examples of safe plastics
How to Find Safe Non Toxic Planting Containers | What Are They?
Well, we have to do a little bit of Sherlock Holmes detective work. One way to determine whether the container is food safe is to use a little bit of simple logic.
I used to work in a restaurant where lots of food was delivered in 5 gallon plastic buckets, pickles, potato salad, etc. Logic dictates that these would be food safe containers.
If you’re going to use a 5 gallon bucket that previously held asphalt, or glue, that might be a clue that it is not food safe.
If you prefer to use a method that’s a bit more scientific than my Sherlock Holmes detective method the following can be a guide for you.
Good – PET ( #1)
PET, or polyethylene terephthalate, is a clear, tough plastic that makes an impermeable barrier. It’s mostly used in soft drink, water, and other beverage bottles, detergent and cleaning containers peanut butter and other food containers and bottles and can be identified with a triangle and the number 1 on the bottom of the container.
PET is considered safe for single use. The idea of using it as a reusable container gets a bit iffy for food storage, because it’s hard to clean. Using it in a garden that consideration becomes less important. It is very easy to recycle.
It is prone to absorbing “flavors and bacteria that you can’t get rid of,” according to National Geographic. Though you may not want to drink from a used PET container, it’s probably safe for gardening.
Good – HDPE Food Grade (#2)
HDPE stands for high density polyethylene. You can identify HDPE by locating a triangle and the (resin identification code) number 2 on the bottom of your container. This type of plastic is used in most 5 gallon containers. HDPE is a dense and stable plastic that is made fairly rigid by its tightly packed molecular structure.
HDPE is used in juice jugs, milk jugs, and water containers, also. National Geographic’s “Green Guide” claims that HDPE transmits no known chemicals into your food. “Urban Organic Gardener” Mike Lieberman grows a full garden in HDPE plastic buckets.
Bad – (#3) PVC +PC
Polyvinyl chloride is not only used in pipes and flooring, but it comes in softer forms that can be used for cheap refillable beverage containers. If you go into a thrift store you’ll see lots of water bottles. I guarantee you will find a number of them are made from polyvinyl chloride or vinyl. They can reach hormone disrupting chemicals into your body, maybe even lead.
Good – LDPE (#4)
LDPE, or low-density polyethylene, is used most in squeeze bottles and garbage bags. You can identify it by finding a triangle and the number 4 on the bottom of your container. National Geographic lists this another “safer” plastic: it transmits no known chemicals into your food. However, because of its natural flexibility, it may degrade more quickly in your garden, leaving bits of plastic behind.
Good – PP (#5)
PP stands for polypropylene, a strong plastic mostly used in caps and lids. You can identify polypropylene by a triangle and the number 5 on the bottom of your container, although many lids do not include this “resin number”. PP has a high melting point and can be “hot-filled” or used with products that need to incubate. It also does not transmit any known chemicals into food. This makes it an ideal material for a garden container, though large PP containers may be hard to find.
Bad – PS (#6)
PS stands for polystyrene is commonly used in Styrofoam containers. While they may be safe for single use they are not recommended for any long-term contact with food. They may leach styrene into your food. Styrene is thought to be a possible carcinogen.
Bad – PLA (#7)
PLA has plastics that contain polylactic acid. The potential is that it includes a controversial ingredient called Bisphenol . (BPA) which is found in hard plastic bottles commonly in use today. They the most common ingredients in baby bottles. Ironically, infants and young children are said to be especially sensitive to the effects of BPA. Recent research is linked BPA exposure to health risks such as diabetes, obesity, and vitamin D deficiency. It is considered a toxic substance in Canada, but is still listed as “safe” in the United States.
Commonalities of Terra-Cotta and Concrete Plant Pots
The main thing you need to take in consideration when choosing a container to grow your plants in is making sure that it drains well.
If your container does not drain well then the roots will rot due to the soggy wet soil. You also want to make sure you choose a container that won’t allow your plant to get too hot while sitting in the sun.
Both type of pots do very well in this department since they are both porous and allow air and water to escape the pot through the walls as well as the bottom.
Concrete pots have good is the insulation value which can protect your plants during wide swings of temperature.
Terra cotta is an excellent choice and perhaps the best one we have readily available to when we consider its use strictly from its comparative benefits to overall plant vitality.
It does suffer in the longevity aspect that they are very prone to breaking. Concrete pots of the hands-down winner in that respect.
Safe Alternatives To Plastic Plant Containers
There is a fairly sharp difference of opinion on whether or not to use plastic containers at all.
If you are worried about being eco-friendly or possible health risks, why not use a different type of plant pot altogether?
There are number of different plant containers available that are not plastic.
- Terra Cotta
- Stone Containers
No matter what type of plan container you choose, there always be pros and cons. It’s up to you to evaluate which works best for you in your circumstances.
An interesting point to ponder was brought up in a gardening forum I was taking a look at. This fellow observed that when considering what type of pots you want to use for your plants are you looking at what’s easiest and best for you, or what’s best for the plant.
Plastic containers offer convenience, are extremely budget friendly, and are in general very easy to work with for the gardener. But from the plants perspective, there might be better choices available. Especially, if you were worried about issues such as health and being ecologically astute.
To sum it all up the safety of your plastic garden containers is an issue for you, we can boil everything down to this:
Plant pots from the nursery can be made with HDPE (2), PP (5)
You Can Use These – non-toxic food safe plastic containers will be marked numbers 1, 2, 4, 5.
Don’t Use These: containers marked numbers 3, 6, 7.
If you are still not sure about how safe plastic is or a little bit uneasy about it, there are plenty of safe alternatives for containers other than plastic.
The intention of this article was to help a concern gardener feel safe the plastic containers they are using are doing no damage to themselves and to the environment. In most cases, by using common sense precautions, that will not be an issue.
We hope you enjoyed this article and as always wish you happiness in your gardening adventures.
Thanks For Visiting.
1. Concrete planter shapes – by theoni via Flickr. Licensed under Creative Commons
2. Terra Cotta planters – Photo By Biz Stone via Flickr licensed under Creative Commons
3 Concrete Variety planters by seewhatyoumean via Flickr under Creative Commons
4. Flowering Cement Plan by viralleaks zone via Flickr Licensed under Creative Commons
5. Planter Boy by angela stark via Flickr Licensed under Creative Commons