Fragile Earth

compost info and tips

What is compost?

Compost is a rich healthy humus type fertiliser and soil conditioner that results from the decay of organic waste. Organic waste is used to describe a waste that was once a living matter such as grass, leaves, vegetable peelings, old flowers and spent bedding plants.  Composting is simply a means of creating the right conditions to speed up this decay of waste.

What actually breaks down the waste?

Microorganisms and invertebrates! Microorganisms (naturally occurring bacteria and fungi) are the hard workers of the compost pile. They feed off organic waste and rapidly reproduce to huge populations that excrete carbon dioxide, water, heat and humus. Invertebrates such as worms, beetles, ants and centipedes act like shredders and removal men. They cut and breakdown the organic material into smaller pieces which the bacteria can then digest more easily and also act as transporters of bacteria throughout the compost pile.

There are three phases of composting, they are;

The initial decomposition phase which is carried out by mesophilic microorganisms. They thrive in temperatures between 15-39 degrees centigrade and readily break down soluble and soft compounds.

As they generate heat they die out and the next phase is dominated by thermophilic microorganisms which thrive at temperatures between 40-65 degree centigrade. This phase is very important as not only does it rapidly degrade tough waste such as proteins, fats and carbohydrates, once the temperature reaches 55 degrees centigrade most human and plant pathogens are killed off.

Once the supply of thermophilic microorganisms is exhausted the compost pile cools down and mesophilic microbes take over again as the compost goes through its curing phase.

What can I compost?

You can compost almost anything that is organic and will biodegrade. That would seem to imply that materials that biodegrade quickly will decompose quickly. This is true, but does not lead to the best compost. The best compost is made up by a mix of carbon and nitrogen based materials in the ratio of 30 parts carbon to 1 part nitrogen. Mixing parts by volume will suffice for garden composting.

Carbon based materials:

Often referred to as ‘browns’, this can include dry leaves, sawdust, straw and corn, newspaper, cardboard, old bedding plants, egg boxes and wood shavings.

Nitrogen based materials:

Often referred to as ‘greens’, this includes grass clippings and weeds, manure from chickens, cows, goats, vegetable peelings, fruits, tea and coffee grounds.

As a general rule you should cut up large ingredients like newspapers, cardboard boxes and vegetable peelings in order to increase the surface area and get a good mix between carbon and nitrogen ingredients. Crush up egg shells and include these as they add calcium to the compost.

Do not compost:

Meat bones or any meat or dairy waste, animal litter, (apart from certain types of organic cat litter), coal and ash, plastics and any inorganic materials such as metals. 

The main conditions that are required are:


There are two types of bacteria; aerobic that needs oxygen to survive and anaerobic that survive without the presence of oxygen. Aerobic bacteria are the hardest workers and are preferred for fast home composting. In order to oxygenate the compost heap, turn it over every couple of weeks.  This is preferable as if the conditions favour anaerobic bacteria there is a likelihood of unpleasant odours occurring.


Compost heaps should be moist to enable the decaying process to proceed but not wet as this will wash out the nutrients and restrict invertebrates such as beetles. Protect your compost heap from rain.

If you can place your compost heap or bin in a warm or only partially sheltered area the composting process will speed up.

When and where to use compost:

You’ll know when your compost is ready as it will have turned a rich brown and should be crumbly. Don’t worry if there are some bits of twig or eggshells; if they are large just put them back into the compost heap. Use your compost all around your garden, to enrich the soil in borders, patio pots, as a mulch and even as a lawn dressing.

Compost Bugs:

You can also consider using Compost Bugs to help the process along. The advantage of using Compost Bugs is that they provide a number of benefits:

Composting done in the traditional way can be very frustrating and if the mix and conditions are wrong it can take up to a year to generate useful compost.

Compost bugs contain unique strains of bacteria that have been developed to:

  • Digest difficult waste such as fats and proteins that indigenous bacteria struggle to digest.
  • Speed up the time it takes to get to the hot and very active thermophilic stage.
  • Contain facultative bacteria which work in conditions where oxygen levels are lower.
  • Start working immediately as high populations of more than 1billion bacteria per gram are introduced into the compost.
  • Reduce odours.
  • Increase fertiliser values.

Kitchen Composter:

The best way to add kitchen waste to your Kitchen Composter is to add your waste and then mix 2 level scoops of bugs in 4 litres of warm water and leave for 20 mins, (or 1 scoop into 2 litres, twice). Slowly pour into your Kitchen Composter bin. Seal and allow to ferment. This will take about 7-14 days. Good fermentation is seen when the material smells like cider vinegar. Add this fermented product to your compost heap and mix well.

For more information on composting take a look at