How to Compost: Feeding Your Plants and Reducing Waste

Learning how to compost is an easy way to make your garden gorgeous by feeding your plants and improving your soil.

Some people believe learning how to compost is too complicated, it smells bad, and it's messy. This may be true if you compost the wrong way, but learning how to compost the right way is actually quite simple. Start with a few layers of organic materials and kitchen scraps, add a dash of soil and a splash of water, and wait for your concoction to turn into humus (the best soil booster around!). This guide explains everything you need to know about how to compost successfully.

compost soil on shovel
Marty Baldwin

Types of Composting

Before you start learning about how to compost, it's important to know that there are a few different types of composting:

Cold composting is as simple as collecting yard waste or the organic materials in your trash (such as fruit and vegetable peels, coffee grounds and filters, and eggshells) to create a pile or fill a bin. Over the course of a year or so, the material will decompose.

Hot composting requires you to take a more active role, but the return is that it's a faster process; you'll get compost in one to three months during warm weather. Four ingredients are required for fast-cooking hot compost: nitrogen, carbon, air, and water. Together, these items feed microorganisms, which speed up the process of decay. During the growing season when garden waste is plentiful, you can mix one big batch of compost and then start a second one while the first one "cooks."

Vermicomposting is another type of composting that is made with the help of earthworms. When these worms eat your food scraps, they release castings, which are rich in nitrogen. You can't use just any old worms for this. You need redworms (also called "red wigglers"). Worms for composting can be purchased inexpensively online or at a garden supplier.

What Is Compost?

Compost is decomposed organic material that is added to soil to provide nutrients to sustain plant growth. Compost also helps to improve soil structure and water-holding capacity, and supports soil microbes that are integral to plant health.

compost bucket
William N. Hopkins

What to Compost

Composting at home is a great way to use the things in your refrigerator that are a little past their prime, which helps reduce food waste. You can also compost certain kinds of yard waste rather than send them to the dump. Collect these materials to start off your compost pile right:

  • Fruit scraps
  • Vegetable scraps
  • Coffee grounds
  • Eggshells (though they can take a while to break down)
  • Grass and plant clippings
  • Dry leaves
  • Finely chopped wood and bark chips
  • Shredded newspaper
  • Straw
  • Sawdust from untreated wood

Never add meat scraps, dairy, cheese, fats/oils, pet waste, or chemically treated wood. These items either cause unpleasant odors or could contain harmful diseases or chemicals.

Keeping a container in your kitchen is an easy way to accumulate composting materials as you prep meals. If you don't want to buy one, you can make your own indoor or outdoor compost bin. For kitchen scraps that could start spoiling quickly, another option is to store them in the freezer until you are ready to add them to your larger outdoor pile.

How to Make Hot Compost

01 of 04

Combine Green and Brown Materials

adding to compost pile
Marty Baldwin

To make your own hot-compost heap, wait until you have enough materials to make a pile at least 3 feet deep with a combination of wet (green) items and dry (brown) items. Brown materials include dried plant materials, fallen leaves, shredded tree branches, cardboard, newspaper, hay, straw, and wood shavings. These items add carbon. Green materials include kitchen scraps, coffee grounds, animal manures (not from dogs or cats), and fresh plant and grass trimmings. These items add nitrogen.

For best results, start building your compost pile by mixing three parts brown materials with one part green material. If your compost pile looks too wet and smells unpleasant, add more brown items or mix your compost with a garden fork to aerate. If you see it looks extremely brown and dry, add green items and water to make it slightly moist.

02 of 04

Water Your Compost Pile

watering compost pile
Marty Baldwin

Sprinkle water over the compost pile regularly so it has the consistency of a damp sponge. Don't add too much water or the microorganisms in your compost pile will become waterlogged and drown. If this happens, your pile will rot instead of compost. You can monitor the temperature of your compost pile with a compost thermometer to be sure the materials are properly decomposing. Or, simply reach into the middle of the compost pile with your hand. Your compost pile should feel warm.

03 of 04

Stir Your Compost Pile

using red pitchfork to build compost pile
Marty Baldwin

During the growing season, you should provide the compost pile with oxygen by turning it once a week with a garden fork or other garden tools. The best time to turn the compost is when the center of the pile feels warm or when a thermometer reads between 130°F and 150°F. Stirring the compost pile will help it cook faster and prevents materials from becoming matted down and developing an odor. At this point, the brown and green layers have served their purpose so it's ok to stir thoroughly and intermix the two materials.

In addition to aerating regularly, chop and shred raw ingredients into smaller sizes to speed up the composting process.

04 of 04

Feed Your Garden with Compost

woman holding dirt with worms
Marty Baldwin

When the compost pile no longer gives off heat and becomes dry, brown, and crumbly, it's fully cooked and ready to feed to the garden. Add about 4 to 6 inches of compost to your flower beds and a thick layer to the top of pots at the beginning of each planting season.

Some gardeners make what's known as compost tea with finished compost. This involves allowing fully formed compost to "steep" in water for several days, then straining it to use as a homemade liquid fertilizer.

Frequently Asked Questions

  • What is a compost starter?

    A compost starter (also known as a “compost accelerator” or “compost activator”) is any additive that you mix in with your organic scraps to boost the natural decomposition process. Compost starters are not required for the composting process but can be good catalysts because they are rich in the carbon, nitrogen, and microorganisms that break down the food and plant matter in your compost pile.

  • How long does it take to make compost?

    Depending on your materials, methods, and conditions, it could take anywhere from a few weeks to several years to make compost. The slowest (but simplest and most passive) method is cold composting, which can easily take a year or more before your pile decomposes. 

  • How much space do I need to make compost?

    You can create a compost pile in a space as small as 1 cubic yard (or 3 feet wide, 3 feet long, and 3 feet deep), but for most gardens, a 3 to 5-foot square space is ideal. If you have a very small outdoor space (like an apartment patio or deck) you can also create compost in a portable compost tumbler or a DIY compost box.

  • What is the first thing that you should place in a compost bin?

    When you're learning how to compost, it's important to pay attention to the order in which you add organic materials. Start with a base layer of twigs and mulch to encourage air circulation. This will also provide drainage. Then you can start adding garden clippings and kitchen scraps for the next layer. Finally, add leaves and wet paper toward the top of the pile.

  • What is the laziest way for beginners to compost?

    If you want to start composting without putting in too much work, you can simply pile up organic matter on the ground. This works best when you're using small twigs, leaves, and grass clippings. Just make sure that there aren't any visible seeds in the mix that will sprout more weeds that you have to deal with later. However, this will take longer than when using a regularly aerated system, and you should avoid placing it near a window because it may give off more odors until things break down.

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