A garden or landscape mulched with cardboard (or heaven forbid several layers of cardboard as part of the science-free lasagna mulch method) is now covered with a tough, relatively gas- and water-impermeable material that will take some time to break down. It's hardly a mulch that's going to nurture soil life.
Cardboard and Paper Concerns
The glue used in cardboard boxes can contain chemicals, but the glue used to form the cardboard itself is derived from starches found in plants like rice, wheat, potatoes, and other tubers. This is perfectly safe to use in your garden and will eventually decompose.
Cardboard boxes are well-suited for container gardening. Simply apply tape to the seams of your leftover boxes, poke a few drainage holes, add a plastic lining and growing medium and introduce your plants to their new home.
Cellulose Materials
In fact, termites will typically only eat the wood inside of a structure for the cellulose material it contains. This, unfortunately, means that any plant-based materials that contain cellulose, such as cardboard boxes, paper or even leaves, could attract termites.
Beneath the layers of compost materials, sheet mulches typically include a layer of cardboard to keep grass and weeds from growing through – a great way to smother unwanted vegetation or convert a sod lawn into a garden.
Though termites can eat some types of wood, they prefer cardboard in taste testing. If they are given no choice and have only wood to eat, they will consume it but their survival rate decreases.
Landscaping fabric adds no nutritional value to the soil, and it doesn't decompose. And over time, the fabric can be detrimental to your soil's health. Biodegradable alternatives like shredded leaves, cardboard, and compost are healthy foods for the soil –– and the hungry earthworms!
In more typical garden conditions — when a piece of cardboard is used as mulch or specifically shredded and soaked to decompose efficiently — biodegradation occurs quickly, with the majority of cardboard completely broken down within three months.
Will roots grow through cardboard? Yes! Unlike silage tarps, cardboard decomposes into the soil making it the perfect element to use in the no-till method.
Also, earthworms are very attracted to the cardboard and are great for the garden, since their movement through soil increases aeration, nutrient cycling, and water infusion. The earthworm 'castings' manure (worm poop) provides an organic type of fertilizer that offers many beneficial nutrients for plants.
This no-dig garden hack is beautifully illustrated in a TikTok video from Brandon Gentry (@brandontgentry), below. Basically, you use sheets of cardboard in your planting area to kill off any existing grass and prevent those pesky weeds from popping up.
You can use it as planters, to start a garden path, mulch a prepared bed, start a new bed and much more. It is important what type of cardboard you use in your landscape. Any cardboard that is not heavily printed, has no tape, no shiny finish, is unwaxed and plain brown is considered clean and okay to use.
How long does cardboard take to decompose in garden? Cardboard can take up to a year to decompose fully, but it does depend on the type you have used.
Why use cardboard in a garden? It's a great mulch, and prevents weeds from sprouting. Decomposing cardboard adds organic matter to the soil, improving your garden's drainage and boosting nutrient levels.
Cardboard takes approximately 2 months to decompose. However, instead of sending your boxes to the landfill consider adding them to your recycling or your compost pile. Cardboard breaks down fairly quickly when exposed to the elements, but stacks of cardboard can take years to decompose.
Gardeners have different opinions on using cardboard in the vegetable garden, but certified organic growers can use what I call 'clean' cardboard – plain, unwaxed boxes with all tape and sticky labels removed, with minimal printing on the outside.
Depending on how and where the cardboard is made, it can contain a long list of chemicals and glue compounds, both of which can leach into the soil. Add to that, many cardboard products also contain man-made ink compounds that can also soak into the soil as well.
Since cardboard is biodegradable, you can add it to a compost pile. It'll break down pretty fast and serve as a healthy form of fertilizer for your soil and plants. The best part is that cardboard is entirely odorless, unlike some other items in a compost pile.
Yes, the cardboard method works nicely for raised beds. It's the same steps used for preparing open, in-ground garden beds. Line the bed with plain cardboard, dampen it, add 6-inches (or more) of good quality soil, compost, or other organic mulch.
Termites were found to prefer cardboard over wood chips as a food source, and rodents such as voles often nest underneath mulch sheets. 2) Newspaper and cardboard sheet mulches were often not as effective as other organic mulches (e.g. wood chips or bark) in preventing weed growth or improving yield.
However, exposure to water or humidity is highly destructive toward cardboard mechanical properties. Water-soaked corrugated cardboard can easily collapse with irreversible shape distortions. Various treatments have been developed to render cardboard hydrophobic including wax layers and nanoparticle treatments.
Add a weed barrier that is permeable to water and air, cardboard boxes are ideal. 'Scavenged' cardboard boxes can be found at appliance stores or bike shops. You can also buy recycled cardboard rolls. Do not use plastic or types of weed cloth which will not degrade.
Corrugated plastic is a waterproof, versatile material that can be die cut the same as corrugated cardboard. Light weight and durable, this material has a decidedly longer shelf life than cardboard and is better at holding out moisture such as snow and rain.
Cardboard can effectively prevent weeds from growing. It blocks the sun from reaching the leaves of the plants underneath, hindering photosynthesis and the plants' ability to grow. It's also difficult for seeds to germinate on the cardboard. However, if organic mulch is added, they may still germinate.
Corrugated plastic can withstand heat, humidity, cold, and moisture, unlike cardboard that can be compromised or fail if they are exposed to moisture, humidity, heat, and cold.