Which Plastics are Safe to Use as Containers to Grow Food?

High-Density Polyethylene

High-density polyethylene (HDPE) is a type of food-safe plastic used in milk jugs, water bottles, trash bags and some buckets, according to the Environmental Protection Agency (EPA). You can identify HDPE by locating a triangle with the number two on the bottom of your container, per the EPA.

Low-Density Polyethylene

Low-density polyethylene (LDPE) is another common plastic also used to make milk jugs, water bottles and trash bags, according to the EPA. You can identify it by finding a triangle with the number four on the bottom of your container.

Similar to HDPE, this type of plastic can be used as sheeting to protect your plants from chemicals in treated wood, according to Iowa State University.

But you may have to replace them often, per the University of Maryland, as this type of plastic can break down.

Polypropylene

Polypropylene (PP) is a strong plastic often used to make caps and lids, denoted by the number five on the bottom of a product, according to the EPA.

PP has a high melting point and is approved for food contact, according to the U.S. Food and Drug Administration. And when it comes to growing plants in plastic containers, this type of plastic is also sometimes recommended as a cover to protect sprouts against elements like frost, per New Mexico State University.

PP fabric liners can also be used to protect plants from the chemicals in treated wood, according to Iowa State University.

Tip

Plant covers are typically only necessary if you're gardening outdoors, per New Mexico State University. Visit your local gardening store for advice if you're concerned about your plants' exposure to weather conditions.

Polylactic Acid

But it may also make for a safe plastic planter for vegetables and other plants. That's because the material is bio-based and compostable, making it less of a concern for soil contamination.

Polyethylene Terephthalate

Polyethylene terephthalate (PET) is a clear, tough plastic mostly used in water, juice and soda bottles, identified by a number one on the bottom of a product, according to the EPA.

While this is more cause for concern if you're hoping to reuse plastic water bottles, it still may be best to opt to grow vegetables in plastic containers made from different types of the material.

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