How To Upcycle Cardboard In Your Garden

April 7, 2023

Whether it’s from online shopping or a recent move, we all know how quickly boxes can stack up. If you find your recycling bin overrun by cardboard, try one of these easy ways to upcycle and reuse cardboard, enhancing your garden while reducing waste. Cardboard is 100% biodegradable and can help with sustainable gardening at home. Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria. Since cardboard is made of paper, when it breaks down, it adds organic matter to the soil in your garden.

While there is not much scientific literature supporting cardboard’s efficiency in permanent landscapes, there is a general consensus it can be a great addition to your annual beds if properly maintained. Permanent, ornamental landscapes, non-maintained sites, and restoration areas are not appropriate locations for newspaper and cardboard sheet mulches. Read the full paper HERE.

Before we get into how to use cardboard in the garden, we must know what cardboard you use and how it will affect your results. The cardboard you are using should be free of all plastic tape and stickers (brown paper tape is ok!). Additionally, be sure to use cardboard free of heavy and excessive print. Celebrate Earth Month and learn how to upcycle cardboard in your garden.

Creating New Garden Beds

This no-till method is excellent if you just moved and want to start a new garden or are expanding a previous garden to enjoy more plants. First, break down your boxes, and remove any tape or labels. Next, mow the area you are starting your garden in and lay the flattened boxes down, being sure to overlap the edges so that weeds cannot grow through the cracks. Finally, wet the area generously with a garden hose. You can add mulch, compost, shredded leaves, grass clippings, or other organic matter to enhance the soil and speed up the decomposition.

The final step is simple; sit back and let the soil reclaim all that organic matter! How long this step takes depends on the biology of your soil and weather conditions. However, the more microbes and earthworms, the faster the cardboard will disappear. If you notice there is still cardboard when it comes time to plant, just cut a hole through the remaining cardboard so you can access the soil underneath and transplant it as usual.

The ideal timeframe for this project is 6-8 weeks before planting, making this an excellent project for the off-season when you are itching to get your garden going. However, as all gardeners know, patience is a virtue. The longer you wait, the richer your soil will be.

DIY Container Gardening

Maybe you live in a condo or apartment, and you are looking to break into the wonderful world of container gardening; perhaps you have a passion for design or DIY, and you’re looking for a new project, or maybe you are looking for a fun way to get kids into gardening. Regardless of your situation, this method is an easy way to reuse cardboard while getting your creative side involved.

It is as simple as using old boxes as planters! First, make sure that you use a thick, sturdy box for the best results. Then, line the inside of the box with plastic from previous packaging or a few of the 2 million plastic grocery bags we know you have to floating around your house. Make sure to poke holes through the plastic and cardboard for drainage, add some potting soil and your plant of choice, then voila! You have a container garden.

This is where it can get fun. Unleash your creative side and decorate your new planter for the best results. The possibilities are endless, and involving the kiddos in raising a new generation of budding gardeners is a great craft.

Check our staff member Tani’s creation! (@garyleedrive)

Filling Raised Beds

Raised bed gardening has recently been rising in popularity, and we can certainly see why. Gardening in a raised bed is an easy way for gardeners with decreased mobility to stay active outside; it can also be an alternative when gardening in an area with poor soil or bad drainage. In addition, since they are above ground, raised beds heat up easier, allowing you to extend your growing season into earlier months.

Positives aside, a significant drawback of a raised bed can be that they are expensive to fill. While your raised bed should have at least 18″ of soil for the plants to grow in, you can line the bottom with cardboard and large branches or logs to fill depth beyond that. You can also line the bottom of your bed with cardboard to deter weeds instead of burlap. Another way to utilize cardboard in raised bed gardening is to cover the bed at the end of the season.

This is a great way to prepare your beds for the next growing season; use the same method when starting a new bed. As a bonus use for cardboard in this regard, you can also use it to lay down the foundation for a gravel, woodchip, or rock pathway around your raised beds. Talk about the ultimate green garden!

Adding Cardboard To Compost

A final easy way to upcycle your cardboard is to incorporate it into your compost. Roughly torn into pieces, the cardboard will rot well in the compost heap so long as it is mixed in with greens and not layered. Corrugated cardboard works even better because the corrugations hold it open until it decomposes. This is a great way to deal with the excess cardboard, all while adding nutrients to your compost.

Great Garden Tip: When being used in compost, cardboard functions as a “brown,” or carbon. For it to break down, you will need to balance it with enough “green,” or nitrogen. Food scraps, plant and lawn trimmings, and weeds without seed heads are all good “greens” for composting.

In Conclusion

It’s important to cultivate consciously. Using cardboard in the garden is a great way to upcycle and enhance your garden to make it more earth-friendly. If you aren’t like the rest of us and don’t have enough cardboard building up, check in with friends, neighbors, or businesses to see if they have cardboard to spare. Here at Great Garden Plants, we chose more sustainable packing options for our customers. Our boxes are formulated with yellow pigment and a copper-free blue pigment to eliminate the presence of copper/heavy metals on our cardboard so you can have even more confidence upcycling our cardboard!

Written by: Lindsey Griffith
Click to read author bio.

Questions, comments, or concerns? Let us know! We have an experienced, knowledgeable staff ready to make sure your garden turns out perfect. Or check out our other blogs, here.