How Many Types of Compost Are There? An Overview of the Main Compost Varieties

Compost is an invaluable soil amendment that provides nutrients and organic matter to enrich your garden beds and help plants thrive. But did you know there are actually several different types of compost? The specific ingredients, preparation method, and end use can vary quite a bit from one type to another.

In this article we’ll overview the main categories of compost and the key characteristics of each. There are far more than just one kind of compost! Understanding the differences will help you select the best compost to meet your gardening needs.

The 4 Primary Types of Compost

There are four main classifications of compost:

1. Garden Compost

This is the classic homemade compost produced by backyard composting. Garden compost makes use of yard waste, kitchen scraps, manure, and other organic materials commonly available around a home.

Ingredients are combined in a compost bin or pile and allowed to break down over weeks to months. Home composting relies on natural decomposition without external heat sources.

Finished garden compost has a dark, crumbly texture and earthy aroma. Particle size varies since decomposition happens unevenly. Home compost provides a balanced nutrient profile.

2. Vermicompost

Vermicompost is a special type of compost produced through vermiculture – using worms to digest organic matter Red wiggler worms are ideal composting worms

Food scraps are fed to the worms, which digest and excrete nutrient-rich worm castings. Their castings contain more microorganisms and plant-available nutrients than conventional compost.

Vermicompost has a very fine homogeneous texture. It’s an excellent choice for seed starting and transplant mixes.

3. Green Manure Compost

Green manure refers to cover crops that are grown and then tilled into the soil to decompose. Legumes like clover and vetch are common green manures.

Their decomposition works like composting in the soil, adding organic matter and nutrients. Allow 4-6 weeks between tilling in green manure and planting crops.

Green manure compost improves soil structure, fertility, and moisture retention in garden beds. It also helps suppress weeds.

4. Farm Manure Compost

Farm manure from cows, horses, chickens, and other livestock can be composted to produce an excellent fertilizer and soil amendment. Straw or sawdust is often added as a bulking agent.

Manure compost requires active management to reach high internal temperatures that destroy pathogens and weed seeds. When done properly, it is very safe to use.

Manure compost provides a broad spectrum of macro and micronutrients plants need. It also contains lots of beneficial bacteria and fungi.

Other Classifications of Compost

In addition to those four main categories, compost can be further classified based on:

• Ingredients used: compost made from yard waste, food scraps, manure, etc.

• Preparation method: actively managed hot compost, passive cold compost, vermicompost, etc.

• Intended use: potting mix, turf fertilizer, soil conditioner, etc.

• Feedstock source: homemade, municipal, agricultural, commercial.

Here are some other types of compost that don’t fit neatly into the main categories:

Mushroom Compost

Also called “spent mushroom substrate,” this is leftover material after mushrooms have been harvested commercially. It contains straw, manure, and gypsum.

Mushroom compost has good drainage and aeration. It can be slightly alkaline, so it helps balance acidic soils.

Leaf Mold Compost

This compost is produced by composting fallen leaves. Leaves are allowed to slowly break down over 1-3 years to create leaf mold.

Leaf mold compost is high in carbon with modest nutrient content. It’s ideal for conditioning garden soil and makes an excellent potting mix.

Seaweed Compost

Composted seaweed harvested from beaches makes a fertilizer rich in potassium, magnesium, and micronutrients. It also contains plant growth hormones.

Seaweed compost introduces beneficial marine microorganisms to soil. Use it to strengthen plant immunity and fruiting.

Bokashi Compost

Bokashi is a Japanese fermented compost product made via anaerobic fermentation. Food waste is typically fermented with a yeast-based bran.

The pickled waste must be buried or added to a conventional compost pile to finish decomposing. Bokashi speeds up composting of kitchen scraps.

Cured Compost

Well-aged or “cured” compost has finished its initial active decomposition and reached maturity. It is stable, pathogen-free, and ready to use.

Curing compost for several months allows it to fully stabilize before adding it to soils. Cured composts have darker color and pleasant, earthy smell.

Potting Soil Mixes

Potting mixes blend compost with ingredients like peat, perlite, vermiculite, sand, and clay to create an ideal lightweight growing medium for containers.

The compost provides nutrients, while the mineral components improve drainage and aeration for healthy roots. Many potting soils also contain fertilizers.

Key Takeaways on Compost Varieties

• There are many different classifications of compost based on the materials used, production method, origin, and intended application.

• The four main compost types are traditional garden compost, vermicompost, green manure compost, and farm manure compost.

• Compost can also be categorized based on specific feedstocks like mushroom, leaf mold, seaweed, or bokashi compost.

• Cured, aged compost has finished decomposing and stabilizing, making it instantly ready for use in gardens.

• Potting mixes blend compost with other ingredients to provide an ideal growing medium for container plants.

• Understanding the different types of compost will help you pick the best compost products to meet the needs of your garden.

No matter what classification it falls under, compost in all its many forms is a vital component of organic gardening. There are lots of options to choose from! Compost truly lies at the heart of building healthy, productive soils by recycling organic wastes into plant nutrients.