Compost is an extremely beneficial soil amendment that strengthens the structure and health of your soil by incorporating organic matter. It can take anywhere from a month to a year or more to make compost, but there are options for those with limited space or time. Some kitchen leftovers can be used directly in the garden with minimal preparation.
Why use kitchen leftovers in the garden?
In 2019, the EPA estimated that the food retail, food service, and residential sectors generate 66 million tons of food waste, of which approximately 60% ends up in landfills. While household kitchen scraps may only be a small portion of this waste, reusing these leftovers through sustainable gardening is an effective way to reduce waste and keep your garden healthy. By reusing common kitchen scraps like egg shells, coffee grounds, banana peels, and orange peels, gardeners can enrich the soil with nutrients and promote vigorous, healthy plant growth while being environmentally conscious.
1. Eggshells
Image: Debbie Wolf/Popular Science
Image: Debbie Wolf/Popular Science
Eggshells, often discarded as waste, offer a variety of benefits for your garden and bird care. As a nutritional supplement for birds, crushed and sterilized eggshells are an important source of calcium for birds, especially during nesting season. To make them safe and pathogen-free, eggshells should be rinsed and baked at 250° F for 10 minutes before placing them in bird feeders. This provides important nutrients for seed-eating birds. Additionally, crushed eggshells act as an effective pest repellent. Creating a barrier around plants helps prevent damage from slugs and snails. For more severe pest infestations, combining with diatomaceous earth may provide additional protection.
Contrary to some belief, placing eggshells in your garden will not prevent edge rot on tomatoes and other sensitive plants, but they can have a positive effect on soil health. Adding crushed or ground eggshells to your soil will improve soil quality and release calcium over time. While it may not prevent certain plant diseases, using them as a soil amendment will aid in the overall maintenance of your garden, improving the overall mineral content and structure of your soil.
2. Coffee grounds
While coffee grounds are often simply viewed as a waste product, they are actually a boon to eco-friendly practices and play a variety of roles in garden care. A mild organic fertilizer, coffee grounds contain essential minerals such as nitrogen, potassium and phosphorus, which, while not effective on their own, can increase soil fertility and support plant health. They should be used in balance with other fertilization methods to ensure long-term soil health.
Additionally, coffee grounds act as a powerful soil conditioner: when mixed into the top layer of your garden soil, they provide nitrogen to the soil, improve soil structure, and increase the soil's ability to retain moisture and air, promoting healthier plant growth.
Additionally, coffee grounds are an effective compost accelerator; their high nitrogen content speeds decomposition in your compost pile, enriching your compost with valuable nutrients essential for plant growth. For optimal composting, we recommend mixing coffee grounds with carbon-rich materials like leaves, straw, and paper to create a balanced environment that promotes efficient decomposition and nutrient release. This multifaceted utility makes used coffee grounds a valuable resource for gardeners looking to adopt more sustainable practices.
3. Banana peel
Banana peels are a rich source of potassium, which is essential for plant growth and health, especially promoting flower and fruit development. This potassium is slowly released into the soil, providing a steady supply of this essential nutrient as the peels decompose. Additionally, the decomposition of banana peels attracts beneficial earthworms, which improve soil aeration and strengthen soil structure, promoting root growth and nutrient absorption.
An alternative method is to soak banana peels in water for a week and use them as a water-based fertilizer. This “banana water” is a nutrient-rich solution that promotes plant resilience and growth by providing large amounts of potassium, an essential macronutrient. It is important to use banana peels in moderation around plants to avoid attracting larger pests and to maintain a balance of nutrients without overwhelming the site with organic waste.
4. Orange peel
Orange peels can be used to keep feral cats from using your garden as a litter box. Orange peels repel cats and act as a natural deterrent to common garden pests such as aphids and ants. The strong citrus scent and limonene in orange peels repel many pests, making them an effective organic way to keep your garden healthy. As orange peels break down, they nourish the soil, helping plants grow and sustain themselves and increasing soil fertility. However, they decompose slowly, so they can be chopped up or dried and powdered to speed up the decomposition process.
5. Nutshell
Nut shells have many practical uses in gardening, enhancing the appearance and functionality of your garden space. Used as a natural mulch, nut shells help retain moisture in the soil and regulate temperature, creating a stable environment for plant growth. Any nut shell can be used, but caution is advised when using walnut shells as they contain juglone, a compound that may inhibit the growth of certain plants.
Besides mulching, nut shells can also be used as a physical barrier to repel pests, improve drainage for potted plants, prevent waterlogging, and promote healthier root growth. The rough texture of the shells not only repels slugs and snails, but also adds aesthetic appeal to flower beds and pots.
6. Cooking water
The water you use to boil eggs or vegetables isn't just waste, it can be a nutrient-rich resource for your plants. Packed with valuable minerals like calcium, this water can be reused to nourish your indoor or outdoor plants. After cooking, cool the water and store it in a milk bottle or watering can, then water as you normally would.
Using kitchen scraps in gardening is a sustainable and efficient way to increase soil fertility and promote healthy plant growth while also addressing the problem of food waste. By reusing common kitchen leftovers like egg shells, coffee grounds, banana peels, orange peels and even cooking water, gardeners can provide plants with essential nutrients to promote strong growth and vitality.
