Not every gardener has the luxury of planting straight into the ground. Some suffer from decreased mobility or limited space. Gardeners that rent or live in apartments also have some restrictions on what they can do.
Using plastic containers is an affordable and easy way to garden. However, many gardeners aren’t sure if it’s safe to grow food in plastics.
Don’t worry – when there’s a will, there’s away! Container gardening means you can set up shop right on your patio or balcony. You can even set up a rooftop garden, depending on your building!
Is it Safe to Grow Food in Plastic?
The short answer? Yes!
However, not all plastics are made the same. Safe plastics include:
- Polyethylene plastic – recycling numbers 1, 2, and 4
- Polypropylene plastic – recycling number 5
- Most clear plastic bottles
- Most opaque food bottles
- Plastic bags made for food storage
- Yogurt containers
Examples of food-safe containers include peanut butter jars (#1), Tupperware (#5), and most 5-gallon pails (#2).
To find recycling numbers, look at the bottom of the plastic container. There should be a small triangle with a number in the middle!
Unsafe plastics include:
- Cling wrap or plastic wrap
- Most PVC (Polyvinyl Chloride) – recycling number 3
- Polystyrene – recycling number 6
- Polycarbonate – recycling number 7
- Un-numbered plastics
If you want to use PVC, look for uPVC, which is made without harmful phthalates.
What to Look for
Look for sturdy, heat tolerant plastics. Many plants need a lot of direct sunlight, which could partially melt certain plastics. Plastics breaking down could leak chemicals, such as BPA, into the soil.
Erosion of the plastic, similar to breaking down from the heat, can also lead to contamination. If the plastic is flimsy, micro-particles will find their way into the soil. These microplastics are unsafe for you and the plant!
Many gardeners find themselves unable to plant directly into the ground. You could have poor soil quality, no-tiller, or mobility issues. Most renters and apartment-dwellers are unable to plant right into the ground. For these reasons, planters and small containers may be your only option.
Plastic containers are lightweight, affordable, and durable. Glass and ceramic containers look pretty but can be expensive and break easily.
Many gardeners grow their own food to save money, so saving money on the containers makes sense.
Growing in containers may also prove best for plants that spread too fast, such as lemon balm and other herbs. It also protects from pesky moles and gophers.
The biggest con is the possible chemical leakage. However, there are a lot of misunderstandings about chemicals. In fact, most chemicals are safe in certain dosages – as long as the plastic is labeled as food-safe, it shouldn’t have harmful amounts of chemicals.
Still, many gardeners want to avoid these chemicals at all costs, making plastic an unsuitable choice.
Another con is water usage. Growing plants in any container mean you’ll probably have to water them more often.
What is the Most Food-Safe Plastic?
According to the FDA, the following plastics are the most food safe:
- High-Density Polyethylene (HDPE), or some beverage bottles
- Low-Density Polyethylene (LDPE), or squeeze bottles
- Polycarbonate (PC)
- Polyethylene Terephthalate (PET), or 2-liter soda bottles and salad dressing containers
- Polypropylene (PP), or yogurt containers
However, food safety doesn’t equal the best to grow food in. Some of these plastics, such as LDPE, are soft and not resistant to heat or light.
Some plastics are FDA-approved before recycling but lose their food-safe label after the recycling process, such as some HDPE plastics.
Upcycled Food Containers
Using the plastic bins that your food comes in is an excellent idea for gardening. If it’s safe for food storage, it’s probably safe for gardening. Look for sturdy, heat-resistant food containers.
If you’re concerned about plastic waste, this is your best option. Rather than buying extra plastic, you can reuse the stuff you would buy anyway.
Options with this method include:
- Yogurt containers
- Soda bottles
- Most water and milk jugs
- Laundry baskets lined with tulle, mesh, or plastic lining
Another great upcycling idea is using plastic crates on top of plants to protect them from local wildlife.
Food-Safe Plastic Sheeting
Thick plastic sheeting is usually made from polycarbonate, which is an FDA-approved plastic. Polycarbonate sheeting is stronger and more flexible than acrylic and glass. It’s also more resistant to the elements than wood.
Plastic sheeting is the most versatile product in this article. Not only can you build custom plant containers, but you can also construct an entire greenhouse from plastic sheeting.
The possibilities are only limited by your imagination. You can build mini plant terrariums for sprouting seeds or an a-frame plant stand. You can create a planter the length of your balcony or one to run along the side of your house. If you don’t have much space, build an A-frame planter!
The biggest downside to polycarbonate plastic sheeting is the price – about 25% higher than acrylic.
You can also use thin, tarp-like plastic sheeting for gardening. Use it to line other containers or lay it out on the ground with a stone barrier for shallow plants. This sheeting is usually made from polyethylene, which is also food safe.
Another great upcycling project involves old Rubbermaid containers.
You’ve probably got a handful of left-over plastic containers with lost lids or cracks – don’t throw them away! Smaller containers like these are perfect for herbs, microgreens, mustard, garlic, and more.
Use big, one to two-gallon Rubbermaid containers for plants such as broccoli, carrots, lettuce, and turnips.
If you’re buying new containers, purchase the Roughneck Rubbermaid containers. Rubbermaid makes these to be weather resistant and tougher than their other containers. They’re made out of polyethylene, which means they’re food safe.
When using these kinds of containers, make sure to drill drainage holes in the bottom before use. You can line the bottom with newspaper to keep the soil from falling out!
If you don’t have plastic to upcycle and don’t want to construct your own planters, plastic pots from gardening stores are a great option. Many gardeners use them when container gardening. They’re usually affordable, and you can find them almost anywhere that sells gardening materials.
You can also find free plastic pots at your local nurseries.
Just like with any container, make sure you are using the right size for your plants. Bigger plants with complex root systems require larger pots.
If you’re limited on space, look for vertical plastic gardens or grow towers.
Final Tips for Using Plastics
Growing plants in plastic is easy – treat it like any other container gardening.
First, clean out your containers. If you’re using a food-storage container, like a soda bottle or yogurt container, you want all the residue gone.
Make sure to add drainage holes to limit over-water. Speaking of watering, you’ll have to do it a lot. Unlike plants in the ground, plants in containers can only rely on you and the rain for their water supply.
It’s also vital to choose the right size. You can’t grow tomatoes in a soda bottle!
Growing in Plastic FAQs
Here are some common questions about using plastic for gardening.
Is polyethylene plastic safe for gardening?
Yes, both high- and low-density polyethylene plastic is food safe. High-density is better for plants that need a lot of direct suns.
Is plastic sheeting safe for gardening?
Yes, depending on the material. Always look for HDPE and polycarbonate sheeting.