March 5, 2025, 2:19 pm | Read time: 4 minutes
Composting is easy — if you do it right. However, small mistakes can slow down the process or cause unpleasant surprises. myHOMEBOOK reveals the pitfalls and how to avoid them to achieve the best results.
A compost heap is a practical way of turning organic waste into valuable gardening material. However, the path to perfect compost is not always as easy as it first appears. Time and again, mistakes are made that slow down the decomposition process, cause unpleasant odors, or even attract pests. We reveal the most common composting mistakes and give you tips on how to avoid them.
Planning Mistakes
1. Placing the Compost Heap on Sealed Ground
If the compost heap is placed on concrete or paving, important soil organisms such as earthworms, which are needed for decomposition, have no access to the compost. In addition, excess water cannot drain away, which favors the development of rot. The compost heap should, therefore, be placed on permeable, unsealed soil.
2. Placing the Compost Heap in the Wrong Location
The location of a compost heap is crucial for the decomposition process. In full sun, the compost dries out quickly, while a site that is too damp promotes rotting. Good air circulation is also important to ensure that sufficient oxygen reaches the heap and decomposition works smoothly. The compost should also be easily accessible so that it can be easily filled and maintained. The ideal place is semi-shaded, well-ventilated, and conveniently located.
Operational Errors
3. Composting the Wrong Material
Meat and fish scraps, dairy products, cooked food, and oils have no place in the compost. They attract pests such as rats, cause unpleasant odors, and disrupt natural decomposition. Treated wood should also be avoided as it can contaminate the compost with harmful substances.
4. Unfavorable Mixing Ratio of Green and Brown Material
A balanced ratio of green and brown material is needed to get the rotting process going and produce good compost. Moist, nitrogen-rich material such as grass cuttings or vegetable waste must be combined with dry, carbon-rich material such as leaves, straw, or shrub cuttings. It is important to add more brown than green materials to the compost. The materials can either be mixed or stacked in thin layers to ensure even decomposition and prevent rotting or drying out.
5. Too Many Grass Clippings at Once
Fresh grass clippings tend to clump together and form an air-impermeable, foul-smelling layer. To prevent this, it should be allowed to dry slightly before composting. It is then either mixed with dry material such as leaves or shredded shrub cuttings or applied in thin layers alternating with these. This keeps the compost well-aerated and allows it to decompose evenly.
6. Compost Heap is Too Wet or Too Dry
The right amount of moisture is crucial for the composting process. The compost should feel like a squeezed sponge. If it is moist but not soaking wet, the microorganisms have the best conditions. Compost that is too wet can lead to a lack of oxygen and rotting, which is why it makes sense to cover the compost during heavy rain or in winter. If it is too dry, decomposition slows down. If it is dry for a long time in summer, the watering can should be used occasionally.
7. Throwing Pieces That Are Too Large into the Compost
Coarse branches and twigs decompose very slowly, as their dense structure makes decomposition more difficult. To speed up the process, they should be shredded with a shredder before composting. The shredded shrub cuttings not only ensure faster decomposition, but their coarse structure also promotes air circulation in the compost.
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Misunderstandings and Expectations
8. Being Impatient
Gardeners often expect compost to be ready for use within a few weeks. In fact, depending on the conditions, it takes about a year for the compost to be ready. Immature compost can be used for mulching, but it is not suitable as a fertilizer.
9. Ignoring the Compost Heap
A compost heap needs regular maintenance. Without turning, not enough oxygen gets into the heap, which slows down decomposition and promotes rotting. Moisture levels should also be monitored: If the compost is too dry, decomposition will stall; if it is too wet, it can rot. Occasional mixing keeps the process in balance and the compost matures into valuable humus.