Living soil is the most natural soil you can get for your plants because it thrives with beneficial microorganisms and is rich in nutrients. If you decide to work with living soil in cannabis cultivation, you can expect resilient plants with a great terpene profile – but there are also some challenges.
Soil is the foundation of life — especially plant life. Rich in nutrients, it gives plants the essential elements for healthy growth and bolsters their resilience against pests and diseases. In nature, the earth is brimming with tiny microscopic lifeforms, which are an integral part of the ecosystem.
When cultivating plants like cannabis, growers can use a variety of different potting soil, often comprised of plant materials, including peat, coir, bark, or minerals like vermiculite. Living organisms are relatively rare in these ready-made potting soils, and nutrients must be constantly added as fertilizers to keep the plants healthy throughout their growing cycle.
An alternative to this is living soil, which is richer in living organisms and closer to nature. Growing cannabis with living soil can be very fruitful, and many growers swear by it.
What is living soil?
Living soil is rich in microorganisms. These microscopic life forms live together in a soil food web, which is a complex and intricate food chain. This self-sustaining life cycle leads to a greater variety of nutrients in the earth. The plants that grow here are not only beneficiaries of the earth; they live in symbiosis with the other inhabitants.
Plants release carbon and sugars into the soil, which the microorganisms can feed on. In exchange, the organisms produce essential nutrients like nitrogen and phosphorus, which the plant can take up through its roots and grow. Everybody wins!
The organisms in living soil
The seven principal inhabitants of living soil are:
These microscopic one-celled organisms break down organic matter, release and recycle nutrients into the soil. Their secretions help to bind together soil particles promoting the formation of so-called micro aggregates in the soil, improving its structure. You could find between 100 million and 1 billion bacteria in one teaspoon of living soil. Soil with a diverse composition of bacteria leads to a more robust and resilient ecosystem and improved plant growth.
Mycorrhizal fungi are critical symbiotic partners of plants and essential for an active soil community. Their hyphae – thin, rootlike structures – grow in the earth and serve practically as extensions to the plant’s roots. They enhance the uptake of water and nutrients like phosphorus. Fungi also help with the decomposing of organic matter. In exchange, plants provide the fungi with carbohydrates, making a perfect trade-off.
Protozoa are single-celled life forms and belong to the domain of eukaryotes. They feed on organic matter like bacteria and organic tissues in the soil, which makes them microbial grazers. Their consumption helps to keep the population of microorganisms in balance. At the same time, protozoa release essential nutrients, especially nitrogen, into the soil.
Nematodes are microscopic roundworms, about one millimetre in length. While some have a bad rep for being pests for cannabis plants, other kinds are the exact opposite. Beneficial nematodes deal with some of the worst pests of the cannabis plants, like fungus gnats, fleas and other unwanted bugs, by preying on their larvae.
These are all kinds of bugs, insects, and other many-legged creatures, such as springtails, mites and millipedes. They break down organic matter and serve as a food source for each other and larger inhabitants. While moving through the soil, they create channels that improve aeration and water infiltration.
Algae do not only live in water, and they are also ubiquitous in the ground. These terrestrial algae perform photosynthesis, produce oxygen, and contribute to nutrient cycling, nourishing the soil food web. Some algae species fix atmospheric nitrogen, making it accessible to plants. Additionally, algae can bind soil particles, improving soil structure and stability. They are, therefore, a tremendous environmental help for cannabis plant growth.
Earthworms are often called tunnel workers of the soil or even ecosystem engineers. They burrow through the soil, move it around and create tunnels through which air and water can flow. Earthworms decompose organic matter, eat unwanted pests and turn them into nutrient-rich castings. Every living soil profits from these helpful friends.
The importance of soil structure
The soil structure is defined by how loose or tight the soil particles combine into larger clusters. Keeping an eye on the soil structure is crucial for optimal water-holding capacity, efficient gas exchange, and enough space for root penetration. Conditions such as insufficient oxygen, excessive moisture, and inaccessible nutrients can occur without proper soil structure.
The major components of living soil
The four main components of living soil are:
1. Organic matter
The organic parts of living soil include the aforementioned microorganisms, as well as living and dead plant matter. This can be fallen leaves, moss, ancient peat or turf, humus, compost, and animal dung. Organic matter comprises the majority of nutrients for the food soil web, holds water and is vital for the structure. Organic matter can make up 10-20% of the soil mass.
Minerals come from the bedrocks out of which the soil was originally formed. They can be classified as carbonates, phosphates, oxides, and silicates and contain macro-nutrients like nitrogen, phosphorus, and potassium, as well as trace elements such as iron and zinc. Minerals contribute to soil structure, influencing water-holding capacity, aeration, and soil health.
Water is a crucial component of living soil – as it is for all life. It dissolves nutrients, making them accessible to plant roots, and enables the physiological and chemical processes needed for plant growth. Of course, it also supports the microorganisms. Without water, the soil is not much more than dead dust.
The loose surface structure of living soil allows air to enter it and enables the lower parts of plants to breathe. The air within the soil is more humid than the air we breathe and has a higher carbon dioxide (CO2) content, which is the plant’s primary carbon source. Oxygen (O2) is especially vital for the growth of plant roots.
Where to buy living soil
You can purchase living soils from various vendors online or in grow centres. When choosing the right product, here is what to look for:
- A reputable and trusted seller
- The ingredients; see if there are any added microorganisms and fungi
- A suitable pH; around six is optimal for cannabis
- Certifications for organic, eco-friendly manufacture
How to make living soil
You can also make living soil by getting your hands dirty, experimenting with different mixtures, and discovering the perfect mix for your garden.
Ingredients of living soil:
The first step is to make a base mix from dry materials like peat moss, coco coir, ready-made base mix, and compost. Add a soil amendment that will help aerate the mix. For this, perlite or pumice is excellent. Start with potting soil as a base mix, and add water to create the desired density.
Next, add more biological organisms through amendments, inoculations, and organisms.
An essential ingredient is earthworm castings, but there are many kinds of nutrient-rich meals, including plants like alfalfa, and animal-based supplements, like fish and bone. There is also the possibility to brew a rich compost tea with nutritious ingredients and add this to the mix.
Creating living soil is not a one-day job. After you have made your mix, you should let it rest for a week or two, so the organisms can develop. When cultivating cannabis in living soil, regularly check the pH and make sure your plants get the right amount of macronutrients nitrogen (N), phosphorus (P), and potassium (K), as well as calcium, magnesium, and boron.
Due to the wide variety of microorganisms in living soil, it does not need as much water as other growing mediums, so be careful, as it is easy to overwater. After harvesting, your living soil can be kept alive and reused numerous times.
Using living soil for indoor and outdoor cannabis growing
So should you use living soil to grow cannabis?
If you are growing outdoors, the answer is straightforward. Your cannabis plants become a part of the ecosystem, and of course, the soil should be as alive as possible. If you want outstanding harvests, it might be advisable, depending on the conditions of your soil, to enhance it first with some external living soil or add nutrient solutions.
For this, you should do a soil test first to learn about the pH level, composition and nutrient content. Then you can add amendments, organic matter and microbes. You can add mulch as straw, wood chips, or leaves to retain soil moisture and suppress weeds. Watch your soil over time and add amendments to maintain its health.
Regarding indoor cultivation, living soil is one option you might want to consider. Growing with living soil is closer to nature and, if rightly cared for, will create an environment that is more nutritious, self-sufficient and resilient. If you will, living soil is more organic and holistic than the more technical and systematic approach, where you measure the composition of your soil and the nutrient supply.
The benefits of using living soil for cannabis plants
1. Enhanced nutrient availability
The diverse microbial population in the living soil helps to maintain a natural supply of nutrients, promotes optimal plant growth and reduces the need for synthetic fertilizers.
2. Improved plant health and resilience
Plants and microorganisms work together in symbiosis. Ideally, this relationship forms a small ecosystem, meaning it has better defences against pests, diseases and environmental stress. The nutrient and water uptake is improved, which enhances root growth and leads to healthier plants.
3. Better terpene and cannabinoid profiles
4. Less watering
Water retention is better than less enriched soils because the living soil is rich in organic matter, minerals, and beneficial microorganisms. This means less need for watering.
The initial cost for ready-made living soil is higher than standard potting soil, but it can be worth the investment over time. Living soil can be used over and over again, and at the same time, you need fewer synthetic nutrients, fertilizers, and pest control measures.
6. Environmental sustainability
Growing with living soil is closer to an organic and natural process. The more self-sustaining the system is, the fewer bottled fertilizers, pesticides, and herbicides you need for optimal health. Furthermore, the more often the soil is used correctly, the better it gets.
Challenges of growing cannabis with living soil
One of the first downsides you might encounter when shopping for living soils for cannabis growing is the initial price. Living soils tend to be more on the pricey side compared to regular soils. However, you should be aware that when you stick with the living soil method, you might get more than your money’s worth since it can be reused multiple times.
You will have to adjust your methods when you are used to growing your plants with regular soil or hydroponic methods. Growing with living soil is more of an organic practice, which means that you, as a gardener, do not have many options to adjust the flow of nutrients, like adding liquid fertilizers.
For beginners, there is a pretty steep learning curve. Growing cannabis with living soil means learning about creating or finding the optimal soil mix for your specific needs. You should care for and maintain the growing ecosystem during your cultivation. Like with other methods, you must closely monitor what is happening in your soil, including the pH and water concentration.
Unwanted visitors are, unfortunately, a problem you might have to deal with, mainly if you use living soil that is self-made from compost. You might bring a population of aphids or other pests in with the mix. Also, seeds from other plants might be inside the mix and germinate. One solution here is to heat up and cook compost before mixing it in, although this also kills a lot of the beneficial life. A more natural method for dealing with pests in living soil is to promote the growth of predatory organisms, like mites.
There are some downsides when it comes to living soil, especially for indoor growing. However, many growers who have taken up the challenge successfully say that the pros, like the excellent terpene profile and the environmental benefits, vastly outweigh the initial difficulties.
Using living soil in cannabis cultivation: nature-oriented, challenging, and rewarding
Living soil is a nutrient-rich growing medium filled with diverse microorganisms, all contributing to the soil’s health and fertility. It creates a symbiotic relationship with plants, enhancing their resilience and nutrient uptake.
Growing with living soil offers a nature-oriented approach to cannabis cultivation, reducing the need for synthetic fertilizers and artificial pesticides. It enhances the resilience of plants, improves nutrient availability, and can lead to fantastic terpene and cannabinoid profiles.
Have you tried growing with living soil before, or do you have advice for those looking to try living soil? Let us know in the comments below, and until next time, happy growing!
Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.