Building humus in the garden: The foundation for healthy soil and strong trees

Healthy soil is the foundation for healthy trees. However, many soils have lost humus in recent decades. Intensive use, frequent tilling, soil compaction, and the removal of organic matter are the main causes of this gradual decline in humus content.

Humus plays a crucial role in soil fertility. It stores water and nutrients, improves soil structure, and provides a habitat for billions of soil organisms. Humus is becoming increasingly important, especially in times of drought, as humus-rich soils can store significantly more water than humus-poor soils.

Anyone who wants to promote healthy and resilient trees in the long term should therefore not only pay attention to irrigation, but also keep an eye on the humus content of their soil.

Key facts at a glance

• Humus improves soil structure and promotes soil life.
• Soils rich in humus are better able to store water and nutrients.
• A high humus content helps trees to better survive periods of drought.
• Compost, worm compost, mulch, bokashi and biochar support humus formation.
• Humus doesn't form overnight, but develops over years.
• Humus build-up not only improves soil quality but also contributes to the long-term storage of carbon.

What is humus?

Humus refers to the entirety of dead organic matter in the soil that has already been partially or completely decomposed. It is formed through the activity of earthworms, fungi, bacteria, and many other soil organisms.

When leaves, twigs, roots, or other organic materials fall to the ground, they are gradually broken down and transformed by soil organisms. This process creates stable humus compounds that can be stored in the soil for a long time.

Humus is a key component of healthy soil and fulfills numerous important functions.

Why is humus so important?

Humus stores water like a sponge.

One of the most important properties of humus is its ability to store water. Humus-rich soils can absorb significantly larger quantities of water and retain it for longer periods than humus-poor soils. Humus can be visualized like a sponge: when it rains, it soaks up water and later releases it slowly to plant roots.

This is particularly valuable for trees. During dry periods, they can draw on these stored water reserves. This reduces the risk of drought stress and makes irrigation more efficient.

Humus stores nutrients

Besides water, humus can also store nutrients. Nitrogen, potassium, magnesium, calcium, and many other nutrients are bound to humus particles and are available to plants as needed. Without sufficient humus, many of these nutrients would be washed away by rain. Humus therefore acts as a natural nutrient reservoir.

Humus improves soil structure

Humus promotes the formation of a loose, crumbly structure in the soil. This creates numerous cavities that can be filled with air and water. Tree roots can grow more easily, and the soil remains better aerated. A good soil structure also improves rainwater infiltration and reduces the risk of waterlogging.

Humus promotes soil life

Healthy soil isn't just made up of sand, silt, or clay. It's also a habitat for countless organisms. Bacteria, fungi, earthworms, springtails, and many other creatures find food and shelter in humus. Together, they ensure that organic material decomposes and new nutrients are released. The more active the soil, the better. soil life The better the natural cycle works.

Humus protects against soil compaction.

Humus-rich soils are generally looser and more stable than humus-poor soils. The activity of soil organisms ensures that new cavities are constantly being created. This allows water to percolate more easily and reduces the risk of soil compaction. 

How can you recognize soil that is low in humus?

Humus deficiency is often manifested through various signs:

• The ground appears hard and compacted.
• Rainwater seeps away only slowly.
  
• The soil dries out quickly, and plants grow poorly.
• Only a few earthworms are visible.
• The soil appears light-colored and not very crumbly.

However, only a professional soil analysis can provide an accurate answer.

How can you build up humus?

Humus buildup is a long-term process. The following measures have proven particularly effective.

Use compost

compost This is one of the most effective methods for building humus. Applying mature compost introduces organic matter, nutrients, and soil organisms into the soil. At the same time, it improves the soil structure. Those with sufficient space can create their own compost heap and thus make good use of kitchen and garden waste.

Use worm compost

Worm compost Worm compost is produced by the work of composting worms and is among the highest quality organic fertilizers. It contains plant-available nutrients, humic acids, and a variety of microorganisms. At the same time, it supports the formation of stable humus compounds in the soil. Worm compost is particularly well-suited for tree care, as it improves the soil and promotes soil life. We highly recommend [product name/brand name]. tree bath worm compost liquid fertilizer. 

use Bokashi

Bokashi This is a form of fermentation of organic kitchen waste. Unlike traditional composting, the materials are fermented in the absence of air. After a maturation period, the material can be incorporated into the soil, where it contributes to humus formation.

mulching

mulching Mulching is based on natural processes, such as those we know from forests. A layer of leaves, grass clippings, or wood chips protects the soil from drying out and simultaneously provides a continuous supply of organic material for humus formation. Mulching is one of the simplest and most effective measures for healthy soil.

Incorporate biochar

biochar It improves the soil's ability to retain water and nutrients. It is particularly effective in combination with compost or worm compost. The porous structure provides a habitat for microorganisms and supports long-term humus formation.

Green manure and ground cover

Bare soils lose humus more easily. Therefore, it can be beneficial to plant green manure crops or ground cover on open areas. These plants protect the soil, promote soil life, and provide additional organic matter.

Which measures are detrimental to humus formation?

• Frequent digging: Regular digging disrupts the natural soil structure and impairs soil life. Many microorganisms lose their habitat as a result.
• Bare soil: Uncovered soils are exposed to wind, sun, and heavy rain. This causes humus to degrade more quickly.
• Excessive use of artificial fertilizers: While mineral fertilizers provide nutrients, they do not contribute to humus formation. If only artificial fertilizers are used, soil quality can deteriorate in the long term.
• Removing leaves and organic material: In nature, a large portion of organic matter remains in the cycle. If all leaves are removed, important nutrients and carbon sources are lost.

How long does it take for humus to build up?

Humus buildup is not a process that can be completed in just a few weeks. Depending on the initial conditions, initial improvements may become visible after a few months. However, sustainable humus buildup usually takes several years.

The most important thing is consistency. Those who continuously add organic matter and protect the soil will be rewarded with significantly better soil quality in the long run.

Humus build-up as a contribution to climate protection

Humus stores carbon in the soil. The formation of humus binds some of the carbon dioxide from the atmosphere long-term. At the same time, humus-rich soils improve water retention and increase the drought resistance of plants.

Building up humus is therefore not only an investment in the health of trees and plants, but also a small contribution to climate protection.