Compost Starters: Here Is Everything You Need To Know

If you are looking to make your own compost, you may have probably heard about something known as a compost starter.

But what does this term mean when it comes to composting?

When you create a compost pile, a few weeks might pass where your pile doesn’t show signs of decomposition. As a result, you become frustrated and begin to look for solutions to get your compost pile started or speed up the decaying process.

Compost starters are products beginner gardeners think about when they realize that the compost pile they built doesn’t start to decay.

In this article, we’re going to cover the whole topic of compost starters, including what they are, whether they’re necessary, different types of compost starters, and how they should be applied in theory.

What are compost starters?

Also referred to as compost activators, compost starters are products or additives that you add to your compost pile to help jumpstart the natural process of decomposition.

Normally, compost starters aren’t required for composting. After all, nature facilitates the natural decomposition of organic material. However, compost starters do serve a purpose in getting those microorganisms started. In caveman terms, they get your pile started.

Compost starters contain nitrogen, bacteria, or a combination of both to get the process of decomposition underway.

Composting is more than just potato peels and grass clippings.

At a microscopic level, organisms like bacteria and fungi naturally decompose the organic materials by releasing enzymes that break down organic matter into simple compounds, such as glucose and amino acids, which can be absorbed by the bacteria.

We can only see termites, worms, and other visible organisms working around the clock to decompose organic matter. However, decomposition begins at a level that can’t be seen with the naked eye. It’s at this level that compost starters prove their worth.

Allowed enough time, any organic material will ultimately decompose.

However, if you feel like it’s taking too long for that to happen, compost starters are a great remedy to get the party underway.

Are compost starters necessary?

A well-balanced compost pile will naturally heat up on its own and decompose.

If you create a conducive environment for decomposition to occur by having the right balance of organic materials, that’s what eventually happens.

Decomposition in any compost pile is significantly enhanced when you create a perfect balance between carbon-rich materials (also known as browns), and nitrogen-rich materials (also known as greens).

Finding the right balance between nitrogen and carbon is crucial in creating the best possible conditions for ever-thriving microbial activity.

Unfortunately, this is where beginners might go wrong.

Oftentimes beginners add too much of one thing, and that results in a slow-decomposing, and sometimes smelly and moist pile.

Side note: Green materials are things such as kitchen scraps, green leaf prunings, and grass clippings, while brown materials are dry things like dried leaves, branches, or twigs.

At different times during the composting process, there is either too little or too much of each type of composting ingredient.

Nitrogen provides microbes with essential proteins, nucleic acids, amino acids, enzymes and co-enzymes necessary for cell growth and function, while carbon provides both an energy source and 50% of the building block of the mass of microbial cells.

Without both, you can’t have a thriving microbial activity capable of breaking down matter, and the microbes may collapse over time.

Assuming that you’re lacking nitrogen in your pile, incorporating compost starters into your compost can be a great way to help rebalance the carbon/nitrogen ratio.

Compost experts recommend that the fastest way to produce nutrient-rich, sweet-smelling compost is to maintain a carbon to nitrogen ratio (C: N) of around 25 to 30 parts of carbon to 1 part of nitrogen, or simply 25-30:1.

It is worth noting that if the carbon to nitrogen ratio is excessively high due to much carbon content, decomposition will slow down.

On the other hand, if the C: N ratio is too low, or there is excess nitrogen in your pile, the chances that you’ll end up with a stinky compost pile are high.

Composting methods and compost starter applications

There are two primary types of composting: hot and cold composting.

Whether you wish to let organic materials decompose at their own speed, or you want finished compost as fast as possible, there are composting methods that are convenient for different goals.

The hot composting method, also called the batch pile composting technique, if prepared adequately, doesn’t require compost starters. Hot composting is the best way to create a rich garden humus that is evenly decomposed.

It is called active or hot because it can reach an internal temperature of 140 ºF and also destroys, typically by cooking, both disease-causing organisms and weed seeds.

The size of the pile and the mix of ingredients are key to achieving the desired temperature in a hot compost.

If you create a pile that is too small, it’ll be more difficult to achieve higher temperatures necessary for hot composting. A hot compost pile should be at least 3 cubic feet but 4 cubic feet is ideal. The pile will eventually reduce in size as the ingredients continue to decompose.

If possible, the compost should be elevated off the ground to enhance air circulation, which you can do by getting a compost tumbler (link to Amazon). The pile should also be placed in a spot where the sun shines, as placing it in the shade might cool down the temperature of the compost and slow down decomposition.

You don’t need a compost starter with hot composting, assuming that you get the right balance of nitrogen and carbon-rich materials, and maintain the pile healthy over time.

What about cold composting?

Cold composting requires less commitment and effort.

You essentially create a pile and let it decompose on its own. You can think of passive composting as an add-as-you-go pile.

The time needed for a cold compost to become mature can be difficult to estimate, but may vary between one and two years. Cold composting can take a little longer to get started so it’s a great candidate for using a compost starter (link to Amazon).

Because cold composting involves adding organic materials as they become available, on most occasions, the moisture level, as well as the brown/green balance, may not be achieved, so you have to take measures.

Compost starters stimulate the decaying process and help speed up decomposition by offering extra nitrogen. This is often necessary when you have a substantial quantity of carbon that counterbalances the little amount of nitrogen available.

Therefore, adding extra nitrogen may lead to an increase in microbial activity as well as an increase in temperature. Though, that might not always be the case.

Different types of compost starters

Compost starters are available in different varieties.

Some are commercial-based, some exist in nature, and others are created by experienced gardeners in the comfort of their own home.

Commercial compost starters

Artificial compost starters are commonly referred to as compost boosters or super-hot compost accelerators.

Whereas some of them are filled with nitrogen-rich ingredients, others contain inert bacteria that once mixed with a compost pile, are instantly active. Some commercial compost starters feature both nitrogen and bacteria.

These products can be quite expensive, but they’re generally effective. One example of a good commercial compost starter is Espoma’s organic compost starter (link to Amazon).

Compost bacteria or Inoculants


Compost inoculation refers to the practice of adding beneficial bacterial o your compost to help trigger microbial activity. Generally, the most appropriate type of inoculation would be to use finished compost.

If you have finished compost at your disposal, you only need to sprinkle a few drops of that particular compost on top of every twelve inches of new organic material.

However, if you don’t have finished compost, you can also sprinkle some topsoil on top of each layer of organic material.

While it may not be as rich in nutrients as its finished compost counterpart, soil contains beneficial bacteria (and worms) capable of activating your pile.

Natural compost starters


The use of natural compost starters in the form of greens can be incorporated into a compost pile to rebalance the carbon vs nitrogen ratio.

Natural compost starters are free and widely available in your garden.

Some common natural compost starters include:

  • Matured manure: This is the most commonly used natural compost activator thanks to its availability. However, if you source manure from your local farmer, you should avoid the ones that are highly fresh because such manure is known to cause excessive bacterial activity and potentially harm the beneficial microbes in your pile. Also, fresh manure has high moisture content, so you need to leave it to dry before adding it to your new pile.
  • Nitrogen-rich organic materials: High-nitrogen organic materials offer the protein-rich components that bacteria and other composting microorganisms need to grow and multiply. Fresh grass clippings, freshly pulled weeds, over-ripe fruits, kitchen scraps, and other moist green organic materials are typical examples of what you can add to your dormant pile to help initiate the decomposition process.

While some gardeners recommend the use of coffee grounds, it is important to know that coffee grounds, though rich in nitrogen, also have antibacterial properties that can potentially interfere with microbial activity.

Additional tips on how to speed up decomposition:

Routinely rotate the pile: This is especially important during the early stages of decomposition when the microbes are concentrated in small pockets. Rotating the pile will help spread the microbes evenly throughout the pile and also deliver some fresh air to your compost.

Don’t forget to moisten your pile: Water is an essential element for the decomposition process. However, also keep in mind that excess water can potentially drown the microorganisms, whereas too little can dehydrate them.

Avoid large compost piles: If you have a large family and you produce lots of waste, your composter will be quickly filled with lots of organic matter. But keeping numerous smaller piles of about four-foot cube is known to help increase the pile’s core temperature for faster decomposition.

Final words

Compost activators are not a must-have component.

After all, a well-balanced compost will naturally heat up and decompose on its own.

However, if you are unsure on how to properly mix organic matter, compost starters can be particularly useful to kick start the decomposition process.

Also, if you’ve opted for the cold composting method, then a compost starter may also be helpful because cold compost often takes a while to become active.