How Long Does It Actually Take To Make Compost?

Last updated on October 23rd, 2023 at 08:31 pm

A well-matured compost needs time for the soil organisms to create the fine crumb structure. But even before that, you can use the compost for soil care.

The three development phases

  • Decomposition phase
  • Conversion phase
  • Building and cooling phase

Decomposition phase

How Long Does It Actually Take To Make Compost?

Start building the compost pile in the spring to allow the contents to decompose over the summer. During the first week or two, the decomposition phase is underway. There are high temperatures inside the compost pile, ranging from 60 to 70 degrees Celsius. Decomposition processes in this temperature range are called hot rotting. The temperatures result from the activity of bacteria and yeasts that break down carbohydrates and proteins. The high temperatures kill germs and bacteria and ensure that the seeds of weeds are killed.

Conversion phase

After hot rotting, the conversion phase begins, which lasts about four to five weeks. Cap fungi settle in the compost and convert fats and waxes into brown humic substances. The temperatures in the compost gradually cool down.

Build-up and cooling phase

In the third and final phase, build-up and cooling processes take place. This phase lasts for several months, depending on weather conditions. Soil fauna, consisting of worms, mites and woodlice, break down the organic material and decompose it into compost.

Fresh compost and mature compost

After about three to four months, you can already use the coarse compost. The compost contains unrotted plant parts such as pruning residues from woody plants or other plant residues that contain cellulose. This fresh compost is used for soil care. You can use it for mulching and apply it as a protective layer to harvested beds. During this time, you can shift the compost around to speed up the rotting process.

During the summer, the compost continues to mature. Under optimal conditions, mature compost will emerge after about four to six months. Because conditions usually vary, you need to allow six to twelve months for crumbly soil with a fresh smell of forest floor to emerge. If you start the compost in the fall, then the rotting processes go dormant over the cold winter. This compost takes longer to reach full maturity.

After a year, the cycle starts all over again. The last remnants of organic matter are broken down. This stale substrate is ideal for growing seedlings and as a potting soil.

Six steps to the perfect compost

How Long Does It Actually Take To Make Compost?

choose a place that is as protected as possible

Because a compost heap should neither be dried out by strong sunlight nor be too soaked by heavy rain, a place under a tree is ideal, which can be a bit out of the way, since a compost heap is not usually one of the visual highlights in the garden.

Decide on a shape

Whether you build an open pile, for which you need a lot of “raw materials”, or use a form or a frame made of wood or metal, is of secondary importance, since good results can be expected in all variants. Thermal composters have the advantage that the heat is kept well inside, which accelerates the rotting process.

do not create a base plate

It is important, however, that the compost lies directly on the ground and is not created on stone slabs, for example, as this allows useful rotting helpers such as earthworms to migrate to it on their own. In addition, excess moisture can drain off better. 4.

Loose piling

The material should be loosely piled up so that there is enough oxygen. Do not compress your compost. Also, do not put too thick layers of one material on the pile, because depending on the material, this can cause disadvantages. For example, a layer too thick with fall leaves may be too dry and lacking in nutrients, while a layer too thick with lawn clippings may be prone to rotting. So mix the materials.

every 3 months

To ensure good rotting, you can move your compost after about 3 months: Shovel your pile over to a spot next to it. This will mix and aerate all the layers again, allowing the pile to mature well. Pre-made compost bins, therefore, often come with 2 or 3 components to turn together.

cover or water if necessary

Throughout the process, the compost should be moist, but not wet. Therefore, you can cover it with mulch fleece, for example, so that both drying out and large wetness after rainfall is avoided. In very dry periods it is useful to water your compost.

What belongs on the compost?

When plant residues or certain kitchen waste are disposed of in the residual waste, valuable substances of the natural cycle are lost. To prevent this from happening, you can either dispose of them in the organic waste garbage can – the contents of which are composted professionally and on a large scale – or, even better, on your own compost. But what exactly can go on the compost?

Valuable raw materials for a compost are:

  • Plant residues from the garden, including flowers and ornamental plants
  • Lawn clippings
  • Leaves
  • Fruit and vegetable residues
  • Coffee grounds
  • Crushed eggshells
  • Tea bags
  • Small amounts of cardboard, kitchen paper and newspaper

Not to be composted or only to a limited extent are:

  • Plants with soil-borne diseases such as cabbage hernia or sclerotinia, or else with late blight, should be disposed of in the household trash because the diseases will survive composting and subsequently be spread throughout the garden, while composting plants infected with powdery mildew is not problematic.
  • Weeds should not have gone into flower yet because the seeds can survive composting. Some garden farms therefore have their own weed compost piles that are left much longer so that the seeds are also decomposed. Root weeds such as goutweed or couch grass should be allowed to dry out before going into the compost.
  • Wood in compact form, i.e. a thick branch, is problematic on the compost pile because it rots very slowly and in addition blocks the energy of many microorganisms. However, if a compost pile is too moist, a layer of shrub trimmings or chopped branches can provide better aeration.
  • Peels from citrus fruits also rot very slowly and are therefore rather unsuitable for compost.
  • Cooked or food scraps of animal origin, baked goods, fat and oil are also not for the compost pile, as they attract rats.
  • Ash is also not suitable, as it is often contaminated with heavy metals.

Leaf compost
To make leaf compost, rake leaves from healthy trees in the fall. Collect it in a separate pile next to your compost pile and leave it there for a year. Fungi will take care of decomposing the leaf compost. There is no need to add compost starter or earthworms.

Green Ear Tip
Did you know that you get the best fertilizer water if you boil fruit peels and vegetable scraps, cut into small pieces, in a pot and then pour the cold water over your plants?

What happens in the compost pile?

Rotting in the compost begins when the microorganisms first break down proteins and sugars. The organisms such as bacteria and fungi multiply greatly, and the temperature in the compost also rises. After about 2 weeks, the temperature in the compost pile can rise to 60 degrees, allowing heat-loving fungi to take over further conversion. However, this so-called hot rot is not achieved in most hobby compost piles because the piles are too small for this and material is usually thrown onto the compost pile gradually. After about 3 months, the temperature drops again to about 40 degrees and the so-called main rotting begins. The compost pile can now be moved. During the after-rotting, substances that are still difficult to degrade are then mineralized.

These are the types of compost you can get

Not all compost is the same

Depending on when you take the compost, you will get different maturity of the compost, which accordingly have different properties.

Fresh compost

But also fresh compost, which you can take out after about 3 months and in which the raw materials are still partly recognizable, can play an important role in the vegetable garden. Since this still contains significantly more nutrients than the mature version, you can take it as a mulch for your strong plants or berry bushes, since you have an excellent fertilizer.

Mature compost

At the end of the rotting process you will have classic mature compost. This can be the case after 6-12 months, depending on the starting materials. It is dark, fine crumbly and smells pleasantly of forest soil. You can now spread about 3 liters of it on one square meter of vegetable bed. Rake it in evenly on the surface. Since immature compost can be harmful for sowing, you can simply sow some cress on a 1:1 mixture of garden soil and your compost. If this germinates and grows without problems, the compost is ripe.

Compost soil

If you wait even longer, the mature compost will become compost soil. The organic content of the compost will break down over time, leaving little fertilizing effect. However, compost is still excellent as a soil conditioner.

Composting in the apartment and on the balcony

Even without your own garden, you can make your own compost on the balcony or even in the kitchen. We show you how:

Balcony composter

  • Get a 75 l container for your compost on the balcony and drill holes in the bottom for better ventilation.
  • Place the container on wooden blocks so that you can place a saucer underneath to collect the liquid.
  • Fill the bottom of the container with shredded branches so that there is good aeration from below
  • Fill the container with suitable materials for composting, always closing the lid.
  • You can add ready compost as a starter
  • If it becomes too wet, add shredded branches, if it becomes too dry, water it a bit
  • If there is an odor, you can add rock flour.
  • Mix the compost from time to time
  • The collected water can be diluted 1:10 and used as liquid fertilizer.

Worm compost
Earthworms liven up your compost pile
Are you in the mood for a new kind of pet? Then you can think about a worm bin. This consists of different areas or tiers, your kitchen scraps – and the worms that go with them. These are specialized in composting.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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