Stop adding these to your trash: 5 common items that'll fertilize your yard for free

You don’t need to spend lots of dollars to have a thriving yard. There are many ways to spend less and still enjoy a vibrant outdoor space. From sowing seeds and taking cuttings, rather than buying plants, to taking care of your garden tools to extend their life.

And instead of paying for expensive bags of compost, you can make your own. What’s more, everything you need is free and is sitting in your household trash can.

“Some of the most effective soil boosters may already be sitting in your kitchen,” says Patrick Martin, owner at Frantoio Grove. “Everyday household waste items, from food scraps to cardboard packaging, contain valuable nutrients and organic matter that can benefit soil health when used correctly, “ he explains.

“These materials can enrich soil, support beneficial microbes, and help plants grow stronger, all while reducing the amount of waste that ends up in landfills.”

Here, Martin shares his 5 top household waste items to save for your compost and how each one benefits the soil.

5 household waste items to save for your compost

1. Coffee grounds for nutrients

Don’t trash your coffee grounds once you’ve enjoyed your morning brew. “They contain nitrogen, potassium, and phosphorus, three nutrients that plants rely on for healthy growth, and can also improve soil structure and support the microbial activity that keeps soil productive,” says Martin.

He explains that coffee grounds are a useful addition to garden soil as they add organic matter which “feed the microbes that help break nutrients down into forms plants can easily absorb.” And he adds that it’s the microbial activity that is the foundation of healthy soil.

However, he warns to be cautious with how much you add. “Grounds are slightly acidic, so applying too much can alter soil pH and potentially suppress plant growth.”

For a good balance, he recommends mixing your coffee grounds into compost, or working them into the soil rather than applying them in thick layers, as a little goes a long way.

2. Banana peels for potassium

“Banana peels are one of the more overlooked kitchen scraps in the garden, but they offer a great source of potassium,” says Martin.

He explains that potassium is an important mineral that plays a role in plant growth, helping to regulate water use, support root development, and improve disease resistance.

So, what’s the best way to use banana peels in your yard? Martin suggests repurposing them by chopping them up and burying them directly in soil near plant roots, or by adding them to a compost pile where they break down over time.

“Potassium is something plants need consistently, and banana peels are an easy, free source of it,” he says. “Chopping them small before burying them speeds up the breakdown process and gets those nutrients into the soil faster. It's a simple habit that adds up over a growing season.”

3. Eggshells to improve soil structure

Martin explains that crushed eggshells add calcium to the soil, and it’s a nutrient that supports cell wall development in plants and contributes to healthy growth. “They can also play a small role in improving soil texture, particularly in heavier soils where drainage and aeration are concerns,” he says.

However, he does warn against expecting too much too soon. “Eggshells break down slowly. Gardeners should not expect an immediate nutrient boost, but over time, they do contribute to soil composition.”

His top tip when using eggshells in your garden is to crush them as finely as possible, as he explains they break down faster when the pieces are small. He also suggests adding them to your compost. “By the time that compost goes into your beds, the shells have had time to start breaking down and become more available to plants.”

And while you’re saving your eggshells to nourish your garden, don’t forget to hold onto your egg cartons as they can be repurposed in your yard too.

4. Cardboard and paper improve soil and suppress weeds

“Plain, uncoated cardboard and paper have a practical role to play in the garden beyond the recycling bin,” says Martin. “Used in a technique called ‘sheet mulching’, layers of cardboard can be laid directly onto soil or grass to block light and suppress weed growth, while still allowing water to pass through to the ground below.”

It’s a simple gardening hack that can save you time weeding, so you can get on with other, more enjoyable jobs in your yard.

“Over time, the cardboard breaks down, adding organic matter to the soil," he adds, “It also helps retain moisture, which is useful during drier months.”

What’s the best way to use cardboard in your yard? “Lay it down, wet it thoroughly, and cover it with compost or mulch. It keeps weeds down and feeds the soil as it breaks down. It's low effort with real results,” he explains.

Cardboard can also be used as part of a no-dig gardening approach to help prepare your beds for planting.

Pro tip
Only non-coated cardboard should be used, as printed or wax-coated materials can introduce unwanted chemicals into the soil.

5. Toilet rolls for growing seedlings

Cardboard toilet roll tubes make surprisingly effective biodegradable seed starters. Martin suggests filling them with potting mix and sowing seeds directly inside. Then, once the seedlings are ready to transplant, the whole tube can go straight into the ground.

“The cardboard breaks down naturally in the soil, meaning roots are never disturbed during transplanting,” he explains. “This approach is particularly useful for plants that are sensitive to root disturbance, where the process of moving a seedling from a plastic pot can set back growth.”

The benefit of using a biodegradable container
Martin explains that by using a toilet roll tube that you then plant directly into the soil, you don’t need to disturb the roots. “When the plant is ready, you plant the whole thing. The tube breaks down quickly once it's in the ground, and the seedling just keeps growing without any interruption. It's a small change that can make a noticeable difference to seedling success rates.”

Getting the right balance

When repurposing these waste items in your garden, Martin advises that none of the materials should be piled on in large quantities. “Think of them as supplements, not solutions. Used thoughtfully and in combination, they can make a real difference to soil health over time, and they cost nothing.”

When you know the benefits that household waste can bring to your garden, there’s no reason to put these items in the trash. Rather than adding them to landfill, put them back into the soil instead.

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