5 Composting Methods That Turn Food Scraps Into Garden Gold

Composting is the process of turning organic waste, such as kitchen scraps and yard debris, into nutrient-rich fertilizer. This transformation is facilitated by microorganisms, including bacteria and fungi, which break down the materials when provided with the right mix of green (nitrogen-rich) and brown (carbon-rich) ingredients, along with moisture and oxygen.

The resulting compost enhances soil health by improving structure, moisture retention, and nutrient levels, while also suppressing diseases and pests. Whether done in a backyard bin or as part of a community initiative, there are several ways to turn organic waste into nutrient-rich fertilizer. Below, composting experts discuss various composting techniques, so you can choose the best method for you.

Hot Compost

Hot composting involves creating a sufficient volume of organic materials to generate heat, which accelerates decomposition, according to author and no-dig gardener Charles Dowding. Although hot composting is the fastest way to achieve nutrient-rich compost, it requires careful management of the pile, maintaining the proper balance of brown and green materials, and ensuring adequate moisture and aeration to enhance decomposition.

Dowding recommends using 3 parts green materials to 1 part brown for a hot compost. "Materials such as coffee grounds are excellent for encouraging heat," he says. This mix raises temperatures, enabling the compost to mature within six to eight months. The process generates temperatures between 110 and 160 degrees Fahrenheit as billions of bacteria break down the green materials.

This method requires just one turn of all the contents, often after a month of adding the last materials. Turning is to mix the materials and aerate the pile.

Cold Compost

Cold composting is the best low-maintenance, beginner-friendly method, in which organic materials are added to a bin or pile over time without turning. Dowding notes that cold composting is a more common method as it allows the caretaker to be hands-off. Materials such as kitchen scraps and fallen leaves are added in small amounts at a time, and temperatures do not increase as much as they do in hot composting.

This slower process takes six months to one year to produce finished compost. "This decomposition is more fungal than bacterial, and it is a very healthy process, but it takes longer than hot bacterial decomposition," Dowding says.

A 3:1 ratio of brown to green materials by volume is a good starting point, but exact measurements are less crucial than in hot composting because cold composting is a more relaxed process. A simple technique is to pile about 3 parts of brown material, then add a layer of green material on top.

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Trench Composting

Trench composting involves burying organic waste in the soil to decompose and enrich it over time. "Dig a trench 6 to 12 inches deep, and the length of your garden bed. Fill it with kitchen scraps and yard waste, then backfill the soil," says Eric Nieusma, co-owner of Maine Hill Farm.

Aim for a ratio of 1 part green to 2 parts brown, or a simple 50/50 mix. Allow the waste to decompose for about six months before planting. "No turning or monitoring is needed because the soil acts as a compost bin," Nieusma notes. 

This process enriches the soil, attracts worms, and improves soil structure. He recommends marking the spot with stakes and suggests starting this project in the fall, because it can overwinter and be ready by spring planting.

Leaf Mold

Leaf mold is a type of compost made exclusively from decomposing leaves. "Leaf mold is all about fungal breakdown, since there is almost no green matter for bacteria to feed on," says Dowding. It is a highly nutritious soil amendment that benefits both soil and plant health. You can use the decomposed leaves at any stage, even after six months, as mulch for plants. However, if you wait 18 to 24 months, the result will be a finer compost.

There are a few efficient ways to make leaf mold—in a bin or pile, or in a bag. Keep in mind that this process does require some effort, including gathering the leaves, shredding them, and maintaining moisture.

In a Bin or Pile

To create leaf mold in a bin or pile, gather fallen leaves and shred them if possible. Shredding speeds up the decomposition. Add the leaves to a bin or a pile located in a shady spot in your yard. Dampen the entire pile using a garden hose, as this moisture will encourage decomposition. Check the leaf pile periodically and moisten it again if it seems dry. Cover the bin with a plastic tarp to lock in moisture and keep the leaves consistently moist.

In a Bag

If you don’t have a bin, you can use a large plastic bag. When storing leaves in a bag, fill the bag three-quarters full and moisten the leaves with a garden hose. Tie the top of the bag securely. Then, puncture holes in the bottom and sides of the bag to allow for airflow. Check the bag monthly and add more water if the leaves appear dry.

Vermicompost

Vermicomposting is the practice of utilizing worms to consume kitchen scraps, which they transform into worm castings you can add to your garden. "This nutrient-rich compost can be used for making garden tea or as a soil conditioner, making it one of the most valuable forms of compost due to its incredible fertility," says Nieusma. Castings are also perfect for seedlings or established plants, as the microbes in the castings help plants' immune systems.

To get started with worm composting, you'll need a worm bin, some red wiggler worms, and a bag of compost. Once your bin is set up, you can add vegetable scraps and cardboard for the worms to eat. There's no strict ratio of brown to green materials; the worms will thrive with either. However, adding cardboard on top helps retain moisture. Keep in mind that there is a slight learning curve regarding what worms can eat, and in cooler climates, you'll need a year-round space, like a basement, to keep the worms happy.

Brown and Green Material

In composting, understanding the role of green and brown material is essential. Greens are high in nitrogen, while browns are rich in carbon. 

Greens supply the nitrogen that fuels the microorganisms that break down organic matter. In contrast, browns provide the carbon needed for energy and help add structure to the pile, preventing compaction and promoting aeration. 

It's important to avoid adding dairy, meat, bones, or fats to your compost pile.

Brown Material:

• Fall leaves
• Pine needles
• Cardboard (without tape or slick coatings)
• Paper (paper plates, coffee filters)
• Corn stalks
• Straw or hay
• Sawdust
• Twigs
• Tree bark

Green Material:

• Grass clipping
• Coffee grounds
• Tea bags
• Vegetables and fruit scraps
• Seaweed
• Annual weeds
• Egg shells
• Bread, pasta, or crackers
• Spent flowers
• Fresh plant trimmings