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SoilFixer Compost Activator (Humification Agent) 

Make your own super compost containing higher levels of colloidal humus and biochar.  (Follow our links to read more about super compost, colloidal humus, and humification)

Benefits of Adding the activator to your compost heap / bin

  • Boost plant growth and crop yield - in our tests by up to 100%  (see note *)
  • Your compost will have more of the vital colloidal humus - it will look and feel smoother and stickier
  • Make a positive, long-term improvement in your soil. Colloidal humus and  biochar  are long-lasting and even small amounts have profound impacts on soil fertility
  • Make a groundbreaking contribution to the environment. Colloidal humus and biochar are stable forms of organic carbon known to survive in soils for hundreds of years. You will be sequestrating carbon and offsetting the impact of global warming gases like carbon dioxide 
  • Our larger pack sizes will typically save you 20% to 40% on a per Kg basis. Our prices include free courier delivery to mainland regions. P&P on other websites can add £8-10/item. 

Be amazed at how much better compost can be!

(* Note:  in our tests, we have seen increases in growth and crop yield of up to 100% (double!) when using Biochar Super Compost (SF60) made from green waste using the composting agent. All plant growth tests are challenging due to the number of variables. We are confident your improved “compost” will deliver at least a 20% increase in yield.

Who should buy it

  • All composters who want to improve the quality (performance) of their compost
  • Home composters using traditional garden (green waste) 'cold' composting in plastic darlex and wooden pallet frame boxes
  • Hot composting systems such as HOTBIN, Ridan and Rocket ® (SoilFixer recognises the owners of these trademarks. Use of the trademark does not and should not be taken to imply any endorsement of SoilFixer products by the trademark owner)
  • Industrial composting sites using windrows or IVC system

How do I use the Compost Humification Agent?

  • Each time you add new waste to the compost bin, sprinkle the agent on the waste and rake it in.
  • Add 100g (one mugful or a handful) per each 5Kg (approx. 7-9 litres, ie a large caddy/bucket) of waste.

The powder promotes and boosts the formation of the highly beneficial 'colloidal humus'  portion of the compost from typical levels of under 5% to 10-40%. This patent-pending NEW super composting process and agent is unlike any existing compost activator (accelerator or inoculation agent). Developed by Tony Callaghan (inventor of the patented hot bin composting system) following years of work on compost and how to make more of the really good stuff that improves plant growth.  (read more at SoilFixer website)


  • A black granular mix, 100% passes through 13mm square mesh sieve
  • Includes small amounts of compost and compost microbes for faster inoculation
  • Includes biochar granules to aid airflow in heap, reduce compost odours and absorb nutrients for later release to plant roots
  • Includes mineral oxides (sources of trace mineral nutrients) 
  • Available in 10 Kg and 20 Kg sacks.

What is it made from?

It is a proprietary formula developed by SoilFixer. The formula contains biochar and micronized powders. The materials are all from sustainable, natural, sources and are 100% organic. (If you are interested in what other commercial activators contain and how they work, read our compost activators review).

Does the activator / agent have a shelf life?

When kept dry there is no shelf life as the ingredients do not deteriorate in air or soil. 

How Do I store it?

In the tub outside, Keep the lid on to prevent rain from getting in. Keep sacks covered to prevent rain ingress


The granular powder delivers so much more than compost accelerators, catalyst, inoculators and activators. Sprinkle the product on to your compost waste each time you add new waste to your compost heap / bin. It promotes and boosts the formation of the highly beneficial colloidal humus. 

How to use / specification
How to use Simply sprinkle one mugful of powder onto each kitchen caddy of waste added to compost heap. This equals: 2% by volume of agent to compost waste 1 part agent to 50 parts compost waste 0.14 litres (mug) agent to 7 litres (a caddy) of compost waste, 1.40 litres (shovel full, or kitchen measuring jug) to 70 litres (wheel barrow load) of compost waste.
Pack size 5 , 10 and 20 Kg sacks. Contact us for pallet loads.
Particle size 100% passes through 10 mm mesh sieve.
Weight Weight varies depending on moisture content: 5 Kg (4.8 kg product + 200g box), 10 Kg (9.7 kg product + 300g box), 20 kg (19.6 kg product, 400g box).

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Compost Activator (Humification Agent)

  • Product Code: CHA
  • Availability: In Stock
  • £24.40

Available Options

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