The living soil movement emphasizes sustainable farming practices that promote healthy ecosystems. This includes the use of natural inputs and holistic nutrient management.
Microorganisms such as bacteria, fungus (like mycorrhizae), protozoa, and nematodes work together to decompose organic material and cycle nutrients. These organisms support plant roots in a symbiotic relationship.
1. Increased Nutrient Availability
When microorganisms decompose organic matter in living soil, they break it down into plant-available nutrients. These nutrients can then be absorbed by roots, allowing plants to grow and thrive. This nutrient cycling helps reduce the need for artificial fertilizers.
The mycorrhizal network of beneficial fungi that attaches to plant roots is also crucial for improving nutrient availability. Fungi secrete acidic or alkaline compounds that help influence soil pH, affecting how readily available specific nutrients are for plants. Fungi can also improve nutrient uptake by forming bonds with phosphate and iron to make them more easily soluble in water and soil solution.
Another group of important soil microorganisms that increase nutrient availability in living soil are bacteria. Bacteria are among the first organisms to begin breaking down organic matter, releasing nutrients into the soil. They also dissolve phosphorus, which allows plants to use this nutrient more efficiently.
A third group of important microorganisms are protozoa. These creatures are a key part of the nutrient cycling process, helping to convert bacteria into plant-available nutrients and then excreting them back into the soil. This process is called phosphorus and nitrogen cycling, and it helps reduce the need for synthetic fertilizers.
The bacterial and fungal communities that live in living soil also produce phytochemicals, which act as natural pest deterrents. These chemicals inhibit pathogens by preventing them from invading the root surface. In addition, they stimulate growth and protect against environmental stresses. This is especially helpful for crop varieties that are vulnerable to disease or insects.
To create a rich and fertile living soil, start with high-quality organic potting soil that is mixed with a combination of compost, coco coir, peat moss, manure, aged tree bark, and worm castings. Incorporate these ingredients into a raised bed or container garden and let the soil “cook” for about a week. During this time, it is recommended to add small amounts of your initial nutrient blend to the soil for the microorganisms to begin cycling and feeding your plants. Between cycles, re-amend the soil with compost or worm castings and replenish any lost organic material.
2. Increased Root Growth
While we often think of soil as an inert and lifeless substance, the truth is that it’s a complex underground ecosystem filled with microorganisms like bacteria, fungi, protozoa, arthropods, and even nematodes. Together, these organisms break down organic matter, cycle nutrients, and create a balanced environment that promotes plant growth.
One of the most important factors for a healthy plant is root growth. As roots extend, they increase the surface area through which water and essential minerals are accessed by the plant. This is especially helpful during times of drought, as the plants’ roots are able to capture and store water for later use. Healthy roots also help secure the plant to the ground, which protects it from being washed away by wind or other environmental stresses.
When a plant is in need of extra nutrition, its roots extend out into the rhizosphere and begin to suck up microorganisms and organic compounds from the soil around them. This is known as nutrient uptake and it’s an important part of the symbiotic relationship between plants and their microorganisms.
In addition, the presence of mycorrhizal fungi in living soil helps to expand the reach of the plant’s root system so that it can access additional nutrients beyond what is available to the plant directly. This is called rhizospheric uptake and is the basis for the ability of living soil to provide more nutrients than standard potting soil.
Lastly, mycorrhizae help to prevent nutrient deficiencies by protecting the plant from pathogens and helping it to overcome stress conditions. For instance, the bacterium Bacillus thuringiensis var. israelensis can kill fungus gnat larvae while the bacterium Azospirillum pulls nitrogen from the air and makes it available to the plant.
To build your own living soil, start with a quality base that contains both sphagnum peat moss and perlite in a ratio of 50/50. Then add in some organic amendments, like wood ash, green manure, and kelp meal. These will help the microbial population in your soil thrive by adjusting pH levels and introducing important elements like nitrogen, potassium, phosphorus, calcium, magnesium, and zinc.
3. Reduced Pest Problems
In a healthy living soil, microorganisms form a complex ecosystem that works to cycle nutrients and create ideal conditions for plant growth while helping to carefully bend your branches. They do this by constructing and maintaining soil aggregates that hold together clumps of little crumbs known as soil particles. These little clumps, which are composed of soil minerals and organic matter, provide habitats for many beneficial organisms such as bacteria, fungi, protozoa and nematodes. In addition to promoting a diverse and healthy soil biome, this also provides a system of checks and balances that can help reduce the negative effects of disease organisms and pests.
The fungi that make up mycorrhizae, for example, form a symbiotic relationship with plants and increase nutrient absorption by extending their root systems into the ground. Some of these same organisms also suppress the growth of harmful organisms by competition for nutrients, production of antagonistic substances or direct parasitism. The bacteria that make up the genus Pseudomonas, for instance, produce toxins that can kill or repel insect pests.
Larger soil organisms, including nematodes, earthworms and pillbugs, help break down and recycle nutrients in the soil. They may also serve as food sources for some of the aforementioned disease-preventing microorganisms or mites, thus forming a system of mutualism and protection.
Finally, the small insects that populate most soils are the foundation of a healthy and balanced ecosystem. These include slugs, snails and the larger spider species that feed on these creatures as well as sap-suckers like aphids, leaf and plant hoppers, mites and thrips. In a healthy soil biome, this mix of organisms serves to protect the soil and the crops by controlling populations of more aggressive pests.
The ingredients in a living soil can vary, but a typical recipe might include peat, compost, coco coir, manure and worm castings. Some specialist companies add rock dust, dolomite lime and custom ingredients, such as powdered beetle shells or crushed crustacean shells, to ensure the right balance of minerals. These components improve the quality of the soil, allowing for increased microbial activity and better aggregation. They also add a range of additional benefits to the growing environment, such as aeration and water holding capacity.
4. Increased Fertilization Efficiency
When soil is alive with beneficial microorganisms and mycorrhizal fungi, it provides a self-sufficient ecosystem for plant growth. These organisms help to cycle nutrients and break down organic matter, helping plants absorb more of the minerals that they need. They also help to prevent nutrient leaching and disease.
These organisms include bacteria, fungi, protozoa and nematodes. Fungi like mycorrhizae, for example, grow in association with plant roots in a symbiotic or mildly pathogenic relationship. They help to make nutrients more available to plants by transporting them from the roots to the leaves or fruit. These fungi also prevent nutrient deficiencies by forming protective barriers around root cells.
To keep the living soil ecosystem healthy, many living soil producers incorporate a mix of organic materials such as coco coir, peat moss, compost, manure, and worm castings into the soil. These ingredients provide a rich food source for the microorganisms and mycorrhizae, and also improve the aeration of the soil and its water holding capacity. Some producers add lava rock, pumice and custom additives such as ground beetle shells and powdered crustacean shells for enhanced calcium and magnesium.
As a result, growing in living soil helps to reduce the need for bottled additives, and a growing period in this type of soil can often be less than a conventional garden soil mix. This can save growers money and time, and reduce the chance of mistakes such as overfeeding which can stunt plant growth or lead to nutrient deficiency and crop failure.
Effective fertilization is crucial to achieving high yields, but the use of traditional NPK fertilizers can be inefficient. These soluble fertilizers can be washed away by rain, and the addition of large quantities of them is likely to lead to overfertilization of the soil. In comparison, the organic nutrient sources that can be used in living soils, such as bone meal or compost, are more efficient for N, P and K fertilization.
While living soil isn’t suitable for all gardening situations, those that do choose to use it often claim verdant growth and a more manageable grow with their plants naturally staying within the nutrient sweet spot throughout the entire bloom phase. This gives growers more latitude for error, and can lead to greater crop quality and higher yields.
