Growing Vegetables In Plastic And What You Need To Know

We are surrounded by plastic, so it is only natural that we use plastic in our gardens to grow food. We will discuss 7 ways how to grow vegetables in plastic, and which plastics are safe to choose from.

There are many practical ways to use plastic in the garden such as plastic plant pots, upcycled plant pots, making a greenhouse, a milk jug greenhouse, row covers, automatic plant waterers, and plastic mulch. However you use plastic in the garden, always choose food-safe plastic. To determine if the plastic is food-safe, look at the bottom for the numbers #1, #2, #4, #5, or a cup-and-fork symbol.

There are many ways you can grow your vegetables in plastic, and you are only limited by your imagination. Plastic can be used very well to grow our food, but we need to understand the potential environmental and health risks associated with it. Here is a guide on how to use plastic to produce food, and how to be safe about it.

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7 Ways To Use Plastic In The Garden

Most things in our lives somehow contain plastic, so it is only natural that we would use plastic in our gardens. Sometimes, a plastic item is the best tool to get the job done. Using plastic in the garden is also a great way to upcycle an old item before it is recycled, or worse, thrown in the landfill. While the copious amounts of plastic produced every day are not good for the environment, we can help the planet by reusing over again the plastic that has already been made.

Some plastic is considered safe to use in contact with food, and some is not. We will go into this in more detail later, but for now, food-safe plastic is designated by a #1, #2, #4, #5, or cup-and-fork symbol. All other plastics should be avoided.

Here are 7 simple and practical ways that you can use plastic to grow food:

1. Plant pots
2. Upcycled pots
3. Greenhouse
4. Milk jug greenhouse
5. Row covers
6. Automatic plant waterers
7. Plastic mulch

Plant Pots

Image by Carmen Edenhofer

Of course, the most common way to grow vegetables in plastic is to use a plastic plant pot. You can buy very attractive ornamental ones, or you can buy hundreds of cheap ones for a few dollars. Unfortunately, there isn't really anything good to say about these. The production of these pots is not good for the environment, so it is not generally a good idea to keep buying new ones. That being said, it is a horrible waste to just throw them away. If you already have them, the best option for the environment is to keep using them until they fall apart. Thankfully, most of them are recyclable.

Throughout the years, we have collected hundreds of various plastic pots from plants we buy or people giving them to us. It seemed the responsible thing to do was to keep using them. As I am writing this, I am surrounded by a small collection of plants growing in old plastic pots.

There is another thing to consider about using pots. Most plastic pots are not made from food-safe plastic. We will go into this in more detail later, but it is important to know that these pots might be (probably are) leaching more chemicals into the soil than is recommended for human consumption.

READ NEXT: 8 Tips for winterizing your greenhouse.

Upcycled Pots

Speaking of reusing plant pots, why not turn an old plastic container into a plant pot? Most of the food we buy these days comes in some sort of plastic container. Before we recycle these containers, why not use them to grow more food? By simply poking a few drainage holes in the bottom, you can create a "new" plant pot that can be used for an indoor or balcony garden or to start seeds that you will transplant into your vegetable patch.

Water bottles or jugs make an excellent growing container for a number of plants. Here is an article about how to grow onions in a plastic bottle to give you some ideas to get started. Using 5-gallon buckets is also a very popular and practical way to grow vegetables (and even some bushes or small trees).

Anytime we can reuse something to grow food is a good way to lessen our environmental impact. And we can still recycle it afterward even it has a few holes in the bottom. Another benefit of upcycling like this is that you can choose a container that is made from food-safe plastic.

Greenhouse

A greenhouse can be a great addition to your garden, and many greenhouses are made from plastic. Plastic greenhouses have the advantage that they are often more durable than glass, so they will still be standing after a nasty hail storm. Plastic greenhouses are also usually cheaper than glass. While cheaper isn't always better, the purchase of one plastic greenhouse for your self-sufficient garden can save countless plastic containers that come with store-bought food.

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Milk Jug Greenhouse

So you want to start plants in your garden, but the weather isn't' quite warm enough for the delicate seedling? Cut the bottom off of a 4L milk jug, and place it over your small plant as a mini greenhouse. You can also take the cap off to create a vent if the temperature or humidity is getting too high under the jug.

Image by Adam Perkins

Row Covers

Plastic row covers have many uses in the garden. They can extend the growing season by acting as a mini greenhouse in cool weather or by keeping frost off of sensitive plants. They can also be used to naturally manage certain pests, by keeping the bugs away from the plants or by keeping birds from eating your harvest. Plastic row covers also help retain moisture around the plants, and shelter the plant from the elements and act as a windbreak.

Plastic row covers can be either held above the crop on a frame or laid over the crop as a floating cover.

Automatic Plant Waterers

You can use an old bottle as an automatic plant waterer. Remove the bottle cap and cut off the bottom of the bottle. Stick the bottle upside down into the soil beside a plant so that the open top is pointing towards the roots. When you fill the bottle with water, it will slowly release the water directly onto the plant's roots.

Plastic Mulch

Plastic can make an excellent, weed-proof mulch. When we want to open a new plot in the garden, we will often cover the grass and weeds with an old tarp or other old plastic sheeting. When we remove the plastic the following year, the weeds have all died back, and the ground is ready for planting after raking the debris or a light till. You can also make this mulched area productive by growing on top of it in pots or using old pallets to create a raised garden bed .

As well as choking out weeds, black plastic mulch has the benefit of increasing soil temperature. We talk about this in more detail in the article about growing potatoes under black plastic .

Is Plastic Safe To Use In The Garden?

Plastic is very versatile and can be very beneficial to grow vegetables. But is it a safe option to use?

The first thing to know, it that all plastic leaches chemicals. Whether it is yogurt you buy from the store, storing leftovers in a container, or growing plants in soil, plastic from the container will leach into it. The question is what will it leach and how much.

Image by J Gargetfrom Pixabay

Food Safe Plastic

There are several plastics that have been deemed safe to come in contact with food. If you look at the bottom of plastic containers, there will usually be a number printed somewhere. If you see the numbers #1, #2, #4, or #5, then the plastic is considered food safe . As we mentioned earlier, you might also see a cup-and-fork symbol and this also means it is food safe.

Yes, these plastics will still leach chemicals. However, the toxicity and dosage of these chemicals are not known to cause any health concerns in people. Here is a very interesting article that goes into this in detail , as well as how to garden so you minimize any potential plastic contamination and keep your food as healthy as possible.

Not trying to scare you into going completely plastic-free, but almost all plastics, food-safe or otherwise, contain phthalates that are known to cause detrimental health issues .

Unsafe Plastic

If you look again at the bottom of a plastic container, any plastics that show the numbers #3, #6, or #7 are not food safe and probably should not be used to grow food. (Interestingly, and a little scary, plant pots are usually #6). These plastics can release unhealthy amounts of toxic chemicals, and they likely contain BPA which is known to be a harmful substance.

That being said, have I ever used any of these potentially harmful plastics in my garden? The answer is yes. When we moved to our farm, we found a small collection of PVC rigid conduit piled in the back corner of a shed. These have become the trellis for our pole beans.

Plastic can be used very effectively to grow vegetables. Use it wisely and make sure you only do what you are comfortable with.

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