Do I Need to Use Compost Activators or Accelerators?

Do I Need to Use Compost Activators or Accelerators?

Do You Need A Compost Starter?

No, save your money!

It’s likely that if you are reading this you have a curiosity about whether you can add compost accelerators into your HOTBIN compost bin. Whether you are a seasoned user of commercial accelerators in traditional and cold composting heaps or are looking to find out more about using the HOTBIN, here we will do a quick overview about why we do not recommend the addition of these products into the HOTBIN.

What Is a Compost Accelerator / Activator / Inoculator?

The terms accelerator, activator and inoculator seem to be used interchangeably across the composting industry and no one seems, or is able to agree on a definition for any of them. In general however these products are designed to kick start, speed up and / or allegedly improve the process of composting. Although the exact ingredient make up of these commercial accelerants is often unclear they are usually high in nitrogen or carbon content and designed to rebalance the contents of the compost bin to improve speed and compost production.

Read more about why the carbon:nitrogen ratio isn’t as important in the HOTBIN. In this post we look at the concept of commercial accelerators and why such products are not needed to either kick-start, speed up or improve the HOTBIN composting process.

What’s is in an Compost Accelerator? (Do You Know What You Are Adding?)

Commercial accelerators / improvers are normally made up of one or more of the following:

Bacteria Culture

  • What is it? A small amount of bacteria to inoculate the waste.
  • Fact: Waste already contains bacteria so no powders or liquids containing additional bacteria are really needed in the HOTBIN to inoculate it. If however it was felt necessary to inoculate (compost inoculation) the HOTBIN in some way it would be easier and more cost effective to simply add a handful of compost or soil as it naturally contains millions of bacteria.

Enzymes (proteins)

  • What are they? These are a biological catalysts that help bacteria digest waste.
  • Fact: Bacteria make their own enzymes, so feeding them waste on a regular basis will serve as a catalyst in itself to keep enzymes quickly breaking down waste material in the HOTBIN.

Ground Up Food

  • What is it? An instant food source for the bacteria
  • Fact: Although ground up food is easy for bacteria to digest the amount of ground up food (in 10g of accelerator) is a tiny amount compared to adding a caddy of food waste (5Kg). So just adding waste (chopped to increase surface area) on a regular basis will provide the bacteria with a sufficient food source.


  • What is it? A soil additive claiming to increase the amount of colloidal humus.
  • Fact: HOTBIN compost is rich and stickier with a high level of colloidal humus. Although bio-char can be happily added direct to the soil in the ground, trials we have conducted suggest the direct addition of a granulated or powder based products into the HOTBIN could block airflow and negatively increase the moisture content inside the unit.

What are the Best Natural Compost Accelerators? 

In composting there are some items which are really easy for bacteria to digest and as such act as great natural accelerators; for example:

  1. Fresh grass,
  2. Food waste,
  3. Blood and bone meal
  4. Chicken poo (pellets).

Although care needs to be taken to control aeration and moisture levels in the HOTBIN, fresh grass for example is an excellent natural accelerator powering some heaps straight to 70°c because it’s easy to digest (high cellulose, low lignin), fast to digest (high surface area, thin), and usually available in most gardens.

In contrast urine, which is recommended in traditional heaps, is NOT recommended in the HOTBIN because of the danger of adding too much liquid to the pile and causing the opposite effect – a cool down.

What Actually Accelerates the Composting Process?

Many commercial compost accelerators claim that products contain “beneficial microbes”. At HOTBIN we believe that you will have all the microbes you need by taking care of bacteria.

Bacteria like the following:

Warmth / Heat

This is the most important compost accelerator. Composting is 32 times faster at 60°C than composting at 10°C (scientific fact based on the Q10 equation that defines the speed of bacteria reactions).
Did you know that there will also be different bacteria in the heap depending on the internal temperature of the HOTBIN? Even when it’s cold (below 5°c) the bacteria in the HOTBIN can be “kick-started” using the hot water bottle supplied.

Small Particles (Bite Size Pieces)

Smaller particles make for speedier decomposition, the reason for this is the size of the surface area available to bacteria. By chopping/shredding waste before adding to the HOTBIN, this provides a large surface area for bacteria to quickly break down the waste – this concept is equally applicable in any composting pile!

Easy to Digest Waste

Heat is released as bacteria consume waste. The easier the food is to eat, the faster the bacteria population grows and the more heat is generated. Generally foods higher in sugar and carbohydrates are consumed faster than wood based materials. Easy to digest waste is typically high in nitrogen such as grass, comfrey, food waste, bone meal and chicken manure.

Making sure you have the right amount of waste, moisture levels, oxygen and temperature will result in happy composting bacteria where the use of commercial accelerators is not required in the HOTBIN composting process.

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