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The main draw for me for this growing style is the reduction of salt based nutrients which ultimately end up leaching in to waterways. Nitrates in particular can lead to ecological problems in marine ecosystems, and they are very energy intensive to produce. Using this method, I don’t water until runoff and I never flush. I was inspired to try it myself when I saw a YouTube video on the channel ‘Mendo Dope’ with Minnesota Nice about growing indoors with a no-till soil. Brownguy420 on YouTube was also a good resource.

There are some misconceptions in their videos. I think they grow great plants, but don’t have a great understanding of some of terminology they use. For instance, Minnesota Nice frequently refers to his potting soil as ‘very loam’. Loam soil refers specifically to the mineral composition of the soils and tends to be fairly equal in its amounts of clay, silt, and sand (silt and sand are usually composed of quartz, don’t provide much in terms of plant nutrients, and are generally not found in any potting mixes). What he really meant by that is that his soil had good structure, was not overly compacted, and had a good amount of aggregation of organic matter.

They frequently also talk about forming a humus layer at the top of their soils, which is not really possible in potting mixes. I will discuss this more later, but a humus layer specifically refers to well-decomposed organic matter in the very top of the topsoil and sits on top of more mineral-heavy layers. In potting soils that are mostly organic matter, this layer of well decomposed organic matter will actually accumulate more evenly throughout the pot (more at the bottom of the pot; generally takes multiple years). There is now a lot of controversy over whether a humus layer as it has been historically defined even exists in soil. Potting soils certainly don’t act much like natural soils or have similar compositions.

What Does It Mean To Be No-Till?

I think in regards to indoor growing, it would be more aptly-named no-dig. We are not really ’tilling’ our pots like a farmer would to a field. However, the concept of leaving the soil undisturbed is similar. Living soils contain a wide array of living organisms including earthworms, arthropods, bacteria, fungi, actinomycetes, protozoa, nematodes, and algae. All of these organisms interact with each other in the soil, and may work syngergistically in breaking down organic matter. They may feed on the waste products of another organism, or may even feed on another organism in the soil. In normal soils, the highest amount of microbial activity is in the topsoil. This is because in most soils, the topsoil contains the highest amount of organic matter. Indoor potting soil mixes, however, are mostly organic matter and are usually well-mixed. Therefore, microbial activity is probably much more evenly distributed throughout a potting soil mix. If using fabric pots, the oxygen levels are likely more evenly distributed as well, promoting microbial activity.

Can potting mixes really be treated the same as a no-till system in natural soils?

This leads to the question of if a potting soil can really be used indefinitely like a mineral soil. Can a potting soil that is probably at least 90% organic matter retain good soil structure and nutrient content by using techniques such as cover cropping/intercropping with legumes, grasses, and brassicaceous plants, top dressing with composts and manures, and adding mulches?

Well first off, unlike natural soils, potting mixes are limited by the volume that can be fit in a container. Treating a soil with no-till methods requires adding more and more organic matter to the soil over time with the goal of having a net positive amount of carbon and nutrients accumulating in the soils. In pots, this will eventually lead to a lack of space and the inability to keep adding more and more materials. I believe this is the main limiting factor in treating potting soil with no-till methods.

Changes to potting mixes over time

Aside from the space issue, there are physical changes to the soil over time. Large organic materials will break down into smaller and smaller molecules. Peat moss, coconut coir, composts, manures, and other plant residues will break down and lose their macro structures as they are digested by earthworms, arthropods, fungi, and bacteria. Eventually, what is left is a material that has historically been referred to as ‘humus’. Humus is a dark brown or black material that is the byproduct of the breakdown of organic matter.

Historical Understanding of Humus

Humus has been thought to be an amorphous material made of large organic molecules. It lacks the presence of cellular structure seen in living organisms. It generally has very few available plant nutrients and is quite stable over time. It resists further breakdown by microbes, it has various phenolic, furan, alcohol, and carboxylic acid functional groups in large molecules bound together by ionic interactions. These molecules are generally classified as humins, humic acids, and fulvic acids. Humins are considered insoluble, fulvic acids are soluble at any pH, and humic acids are most readily soluble in very high pH solution.

Fulvic acids and humic acids are chelators that bind to positively charged ions including nutrients such as ammonium, calcium, iron, and any other positively charged nutrient. They have also been proposed as chelators of heavy metals that help protect plants from toxicity. Thus, they increase the cation exchange capacity of soils allowing for better retention of nutrients. Furthermore, negatively charged fulvic acids that are soluble may deliver bound nutrients directly to the root zone. Fulvic acids and humic acids have also been proposed to positively effect plant growth and plant health through stimulating plant hormone and reactive oxygen species pathways leading to improved growth, nutrient uptake and transport [1, 14].

Criticisms of the Old Model of Humus

If humic substances accumulate in soils and resist further breakdown, why does the humus layer not keep growing indefinitely in size? Well, new research has found that these large humic molecules that resist further breakdown don’t actually exist naturally in soils. In the past, humic acids were characterized by first performing soil extractions with a highly alkaline sodium hydroxide solution. The extracts were then fractionated and hydrolyzed with acid solutions and the molecules that were soluble at low pHs were determined to be fulvic acids, whereas the molecules that remained only soluble in high pH solutions were classified as humic acids.

Recent studies have shown that without the alkali extraction, these molecules do not exist naturally in soil, and therefore, humic acids and fulvic acids are actually created during the extraction process. The humus layers in soil do not actually have these novel stable compounds that have been reported for so long. In fact, the humus layer is really just organic matter in various stages of decomposition [2, 3].

The Contentious Nature of Soil Organic Matter, by Johannes Lehmann & Markus Kleber

The main takeaway here is that it is not true that you need to purchase ‘humic and fulvic acid’ products before your soil has developed a ‘humus layer’. Observed vigor when plants are grown in soils with a ‘humic layer’ is likely due to a higher amount of well decomposed organic matter that is more readily mineralized by microbes than larger organic matter. Adding organic matter in various stages of decay (such as adding compost or vermicompost) into a potting soil with larger organic matter will more closely resemble this situation and establish a continuum of organic matter in various stages of decay. Humic and fulvic acids still have benefits to plants, just understand that they are synthetic and will not be naturally produced in your soil over time.

Of course, potting soil will break down over time and undergo humification, but I believe they can indeed be sustainably reused over time (until a space capacity is reached). It is important to realize that as the organic matter breaks down, there may be compaction that needs to be dealt with.

How to Deal With Soil Compaction and Decomposition

There are a few good tools to deal with this issue in potting soil mixes. In my opinion, these are the best ways to keep your potting mixes sustainable:

Earthworms- Help with soil porosity by boring through the soil and forming tunnels. Water infiltration can be increased by 4 to 10 fold when earthworms are actively forming tunnels [5]. In addition, they can help homogenize a no-till system by consuming fresh organic matter at the soil surface and redistributing the organic matter throughout the pot through their castings. Earthworms also greatly increase the nutrient availability of the compounds in the organic matter. Earthworm populations do not do well with tillage, and soil tillage (digging) can greatly reduce the population of earthworms in the topsoil. They prefer to have organic litter on top of the soil to feed on. Furthermore, soils with active earthworms appear to have fewer pathogens [15].

Help with soil porosity by boring through the soil and forming tunnels. Water infiltration can be increased by 4 to 10 fold when earthworms are actively forming tunnels [5]. In addition, they can help homogenize a no-till system by consuming fresh organic matter at the soil surface and redistributing the organic matter throughout the pot through their castings. Earthworms also greatly increase the nutrient availability of the compounds in the organic matter. Earthworm populations do not do well with tillage, and soil tillage (digging) can greatly reduce the population of earthworms in the topsoil. They prefer to have organic litter on top of the soil to feed on. Furthermore, soils with active earthworms appear to have fewer pathogens [15]. Cover Crops/Intercropping [16]- Cover crops such as crimson clover, hairy vetch, ryegrass, and rapeseed can be used to increase soil infiltration. Rapeseed tends to have a large taproot that can easily drive down to the bottom of a pot and help provide aeration and inject fresh organic matter deep into the soil. Hairy vetch and crimson clover are legumes that are useful for nitrogen fixation, and of course their roots also provide organic matter and infiltration. Grasses such as ryegrass typically do not have a large taproot, but do have very prolific root systems and are fantastic green mulches for increasing fungal activity in the soil.

Cover crops such as crimson clover, hairy vetch, ryegrass, and rapeseed can be used to increase soil infiltration. Rapeseed tends to have a large taproot that can easily drive down to the bottom of a pot and help provide aeration and inject fresh organic matter deep into the soil. Hairy vetch and crimson clover are legumes that are useful for nitrogen fixation, and of course their roots also provide organic matter and infiltration. Grasses such as ryegrass typically do not have a large taproot, but do have very prolific root systems and are fantastic green mulches for increasing fungal activity in the soil. Microbial Activity (Fungi and Bacteria)- Both fungi and bacteria are very important for the formation of soil aggregates. A soil aggregate is essentially matter that is ‘glued’ together and remains stable when watered. Channels that allow for water infiltration form in between aggregates.

What is a soil aggregate? [5]

Soil molecules are brought into contact with each other through physical processes and may weakly associate with each other through ionic interactions. Aggregates can become stable through the filamentous growth that binds aggregates together such as plant roots and fungal mycelium. Earthworms can help form aggregates through their excrement. However, microbial activity is probably the most important. Aside from fungal mycelium physically holding aggregates together, fungi and bacteria can release metabolites into the soil such as gums, waxes, polysaccharides, and glycoproteins. For instance, Glomeromycetes form mycorrhizal associations with plant roots and secrete a glycoprotein known as glomalin into the soil that helps stabilize aggregates. Glomalin activity appears to be reduced in heavily tilled soils.

What Kind of Earthworms Should I Add?

I recommend adding a variety of species of earthworms. Some species of worms may be better at feeding at different depths of the soil. For instance, red wigglers are thought to be good at feeding on organic matter near the soil surface, whereas nightcrawlers are better at feeding on more decomposed matter further down in the soil [17]. I have added both of these species of worm to my pots as well as a native species of earthworm that I collected from my yard. I added about 5 nightcrawlers, 15 red wigglers, and 15 native earthworms to each 10 gallons of soil. I am not really sure what to expect from the amount I added, and I am not sure if one species will do best and outcompete the others or if they will find their niches in the soil.

What about the nematodes and the arthropods in the soil food web?

Nematodes are basically small worms. Numerically, they are the most abundant animals on the face of the earth, and there are tens of thousands of different species that occupy a vast number of ecological niches. In soils, different species may feed on fungi, bacteria, insects, other nematodes, and some are parasitic to plants. Therefore, they play important roles in nutrient cycling, disease control, and a balanced soil ecosystem [20]. Many nematodes are naturally introduced in to your soils through the use of composts. However, if you are having insect problems in your soil, three beneficial nematodes are commonly used as additives: Heterorhabditis bacteriaphora, Steinernema feltiae and Steinernema carpocapsae. In particular, S. feltiae is particularly useful for helping control fungus gnats and thrips [21].

I normally don’t add insects to my soils. Though insects such as millipedes, pill bugs, or sowbugs may assist in breaking down organic matter, they really aren’t necessary and may do damage to young, tender transplants. I rely mostly on worms for helping to break down the larger organic matter. In regards to smaller arthropods such as mites, many soil mites will be inoculated in to your soil with the compost you add. They are useful as well for breaking down decaying organic matter [22]. Similar to beneficial nematodes, there are predatory mites that can be added to your plants and soils if you are having issues with certain arthropods, specifically whiteflies, thrips, fungus gnats, and mites such as spider mites and russett mites. There are different species of predatory mites that are commonly added for pest control, and each one has different lifestyles and does best under different environmental conditions. I recommend looking at the following site to help determine what kind of mite will best help you with the pest you are dealing with in your particular environmental conditions: https://www.chascience.com/predatory-insects

What Cover Crops Should I Plant?

For the reasons talked about earlier, my cover crop mixture contains crimson clover, hairy vetch, rapeseed, and ryegrass.

Normally, a cover crop such as this would be planted in the winter, after harvest of an outdoor crop. It would be allowed to grow until the next planting season, at which point it would be cut down and a mulch or compost would be placed over the crop residue.

They can also be treated similar to an intercrop. For instance, I am growing indoors and wanted to begin growing soon after preparing the soil, so I decided to grow my cover plants at the same time as my Cannabis plants. I transplanted the clones to the center of the pots and seeded everywhere except for a 4 inch perimeter around the clone. I then covered the unseeded area in compost.

It can take up to 6 weeks for legumes to begin fixing Nitrogen [18], so it is important to leave them planted throughout the life cycle of the Cannabis to contribute a net gain of Nitrogen to the soil (or at least 2 months). To avoid intercropping, have pots that you cycle between for your Cannabis, and plant the cover crop mixture on pots you are not currently growing in.

How Do I Stimulate Soil Microbe Activity?

The number one way to stimulate microbial activity is by adding organic material to the soil. Earthworm castings, green manure, compost, mulches etc. Having active soil biology including worms and arthropods can help with keeping microbes active in the soil. However, I also tend to use microbial additives including compost teas and prepackaged microbe inoculants.

What’s the Deal with Compost Tea?

There is some debate regarding the value of compost tea. Undoubtedly, there are small amounts of soluble nutrients in the compost tea, but the main ‘selling point’ on compost tea is the claim that it inoculates soil with microbes and helps feed the microbes already in the soil. Compost teas can be made a variety of ways, but the only compost teas I have ever made are aerated. Healthy soils are not rich in anaerobic bacteria, so I don’t see a lot of value in making anaerobic compost teas. Many soil bacteria are facultative anaerobes, meaning they can grow in environments with and without oxygen, so unaerated teas may be useful in growing these bacteria, but these same bacteria can grow in aerated teas.

Of course, adding compost directly to the soil will add the same bacteria to the soil, but when you grow in containers and are limited in space, I think that compost teas are a good way to continually inoculate your soil with microbes. In my opinion, just steeping compost in water is not the best way to make a tea, as there isn’t enough simple carbon and nutrients for vigorous microbial growth. I view compost as the source of inoculum in the compost tea, and then I add amendments to support rapid growth of microbes.

What do I put in my compost teas?

Compost – I think it is best to use a high quality, local compost made with a variety of organic matter. It should at least have some sort of animal manure such as rabbit, chicken, cow, horse etc. Personally, I don’t make my own compost and to be honest, the compost I use is not of the highest quality. I use cedar grove compost because it is very cheap and available at a store near me. It contains no animal manures unfortunately, and is made from kitchen waste, yard trimmings, and food products. It also tends to have little pieces of trash because it is made from peoples’ waste. I use a few handfuls of this in a mesh strainer bag for 5 gallons of actively aerated compost tea (AACT).

– I think it is best to use a high quality, local compost made with a variety of organic matter. It should at least have some sort of animal manure such as rabbit, chicken, cow, horse etc.

If you want to buy a high-quality compost online because you don’t have access to a good local compost, the following compost has good ingredients:

Vermicompost or vermicompost extract- Many consider vermicompost to be the ideal compost for plant growth. I have recently established a worm bin to get a consistent source of earthworms and earthworm castings, but in the meantime I have been using vermicompost extract from Terra Vesco. I don’t measure it, I just splash a small amount into the tea. Recommended dilution rates are 5%-10% which would work out to 4-8 cups in a 5 gallon tea. However, I am not using this as my only nutrient and microbe source, so I use less. I would estimate that I usually end up adding about 1 cup of it into my teas. I will stop using this once I get a consistent source of vermicompost, at which point I will add the vermicompost to another strainer bag in my aeration bucket.

Fish and Kelp Blend – This liquid additive is a 2-3-1 organic liquid fertilizer. I only add a few tablespoons of this to my 5 gallon tea. Kelps such as Ascophyllum nodosum have been demonstrated to enhance plant growth hormone levels in plant tissues. They also contain fatty acids such as arachadonic acid that act as plant systemic acquired resistance (SAR) activators [11, 12]. Fish hydrolysate is enzymatically digested fish that contains lots of proteins, amino acids, fatty acids, and available nutrients. Fish hydrolysate promotes fungal growth in compost teas, leading to a more balanced tea that is not dominated completely by bacteria. While it has available plant nutrients, the microbial growth in the teas may assimilate some of these available nutrients into more complex organic matter.

Insect Frass- I also add the frass (castings and exoskeleton remains) of black soldier fly larvae to my compost teas. The frass I use is rated as a 4-2-2.5 fertilizer and has various other benefits. Insect frass contains chitin due to insect exoskeleton remains. Chitin is also found in crustacean shells and the cell walls of fungi. Plants have receptors in their cell membranes that bind to chitin and trigger expression of disease resistance genes, so insect frass may help prime plants for disease resistance. Furthermore, insect frass is rich in microbes including bacteria and protozoa and provides a good source of food for fungi. I add about a tablespoon of this to a 5 gallon AACT.

Down To Earth Acid Mix – I don’t tend to use much of this in my soils because it contains cottonseed meal which can lower soil pH some. However, it contains the following ingredients: Cottonseed Meal, Fish Bone Meal, Langbeinite, Rock Phosphate and Kelp Meal. It also contains humic acids. Rock phosphate and kelp meal are common additives for fungal dominant compost tea recipes, but the other ingredients certainly don’t hurt anything in terms of providing a more diverse source of food for microbes. Humic acids are also effective chelators. I only add about a tablespoon of this to the 5 gallon bucket (I add it into the pouch with the compost so the actual material doesn’t go in to the soil.

Unsulfured Blackstrap Molasses – This is added as a simple sugar source to help amplify the amount of microbes (mostly bacteria) in the compost tea. Molasses contains very small amounts of available plant nutrients and is not very useful as a fertilizer. I am of the opinion that any source of sugar can replace molasses, but many people swear by only using molasses, especially people that don’t want to use anything too refined or not organic. I do not use much of the molasses; I usually use 1-2 tablespoons in the 5 gallons of tea. Using sugars such as molasses tends to favor a more bacterial tea whereas more complex organic matter such as kelp, fish, or insect frass tend to favor a more fungal dominant tea. I don’t believe it is well understood what the ‘ideal’ compost tea for Cannabis is, but I tend to try to make my teas with a variety of different food sources for microbes to try to diversify the microbial life in my teas as much as possible. However, if I was to leave out one food source from my teas, I would leave out the molasses. I believe that the more complex organic matter that I add also supports some amount of bacterial growth. However, I like to make a relatively balanced tea, and I like to add the molasses to have good bacterial proliferation as well as fungal growth. I have never quantified the microbes in my teas, though.

Soluble Silica – This additive is not very important in my opinion. I mostly add it just because I have excess of it but I don’t plan on adding it after flipping to flowering light schedules. Silicon is important for stress tolerance and strong structure, but dicotyledonous plants such as Cannabis generally accumulate less silicon than monocots [13]. I use straw mulches and rice hulls in my soils, so I should have more than enough silicon in my soil already. However, it likely benefits the ryegrass that I plant as a cover crop as well.

Microbe Additives

In addition to compost teas and compost mulches, I use microbial amendments. My go-to additive is Recharge. It is a microbial inoculant that contains arbuscular mycorrhizal fungal species, Trichoderma fungal species, and Bacillus bacterial species. Bacillus and Trichoderma species act as decomposers as well as biocontrol agents of pathogens, and mycorrhizal fungi form associations with plant roots to help provide nutrients (primarily phosphorus) to plants. Initially, during soil preparation, I sprinkle recharge into my soil mixture. I also sprinkle some onto the root ball of the clone or seedling I am transplanting into the soil. Finally, I sprinkle a small pinch of it onto the soil surface before each watering or feeding.

There are comparable brands to recharge including Great White and Mikrobs (both of which actually have more diverse arrays of microbes in the mixture). In fact, I would probably recommend Great White just for the amount of microbial diversity it has, but it is a bit expensive

Other recommended microbial products include Tribus and Mammoth P. Both Tribus and Mammoth P are marketed as bacteria blends that are useful for Phosphorous cycling. Tribus has three Bacillus species, but all of them can also be found in Great White and two of them can be found in Recharge and Mikrobs. Mammoth P, however, is a formulation that has unique bacterial species not found in other microbial mixes: Enterobacter cloacae, Citrobacter freundii, Pseudomonas putida and Comamonas testosteroni. These bacteria were chosen for their high phosphorous cycling ability in soil. Therefore, I think Mammoth P would be a good addition to Recharge, Mikrobs, or Great White.

I think that microbial amendments can be useful in promoting root growth, nutrient uptake, and biocontrol, but they certainly aren’t necessary for good plant growth and you should not break the bank buying them. I think that Recharge and Mikrobs are both relatively affordable and a little bit can go a long way. You could even get away with doing a one-time application at transplant, you don’t need to apply them as frequently as I do. I don’t personally use Mammoth P, but I think it would be worth experimenting with and seeing if the benefits you get from it are worth the price tag.

You can get a microbially active soil just from compost, these additives are not necessary, but there are a lot of positive reviews and anecdotal evidence supporting the use of these additives, especially those with mycorrhizae.

How Do I Prepare a Potting Soil for No-Till Systems?

You can make this as simple or as complex as you would like. I like to try to include organic matter in various levels of decomposition, a good amount of aeration, microbial-rich materials, mineral amendments, and some nutrient-rich organic matter. First start off with a good base mix. One simple mix I like is: 20% Canadian sphagnum peat moss, 20% high-quality coco coir, 25% high-quality compost (can be compost, vermicompost, or a mixture), 15% rice hulls (provides aeration and organic matter as well as silica), and 20% small black lava rock or pumice (I don’t recommend perlite in no-till mixes because of its propensity to get pulverized over time).

Next up, I like to add amendments besides the compost that may add microbes to the soil.

Sprinkle a thin layer of Recharge or a powdered microbial additive of your choice over the soil mixture. It is not necessary to add a large amount; the microbes will multiply by themselves, plus you will likely do extra additions throughout the grow. If you are using Tribus, Mammoth P, or another liquid microbial additive, wait until your first watering to add it.

Add about 1/2 cup of insect frass for every cubic foot of potting mix. This will add more microbes and will also provide a good amount of plant nutrients and organic matter.

Minerals

Since the potting mix has very little mineral content, it is important to add minerals to your soils. If you are trying to save money, it may be good to choose one of the two following materials. If you want to maximize mineral diversity, it may be a good idea to mix both of them into your soil.

Azomite- Azomite is volcanic ash mined from a seabed. It has an NPK rating of 0-0-0.2, but its main value to soils is it contains over 70 trace minerals and elements. Add about 2/3 of a pound of azomite (1 cup) for each cubic foot of potting mix.

Greensand– Derived from the mineral glauconite, greensand has a similar NPK ratio and trace mineral content as Azomite. However, relative ratios of micronutrients are surely different than that of Azomite. For instance, greensand has a higher amount of total potash and iron than Azomite. You can add 2/3 of a pound (1 cup) of greensand for each cubic foot of potting soil.

If you are using both greensand and azomite, add 1/3 of a pound (1/2 cup) of each

For more long term phosphorus and calcium, I recommend adding some soft rock phosphate. Be aware that this is different than hard rock phosphate. It still contains elements that need to be mineralized by microbes over time, but it can be broken down within a reasonable timeframe for no-till potting mixes.

Soft rock phosphate has an NPK ratio of 0-3-0, with 3% soluble phosphorus available to the plant. However, it contains up to 20% total phosphate that will be released over time through the activity of microbes such as mycorrhizae or phosphorous cycling bacteria such as those found in Mammoth P (and naturally in soils).

Soft rock phosphate also has approximately 20% total calcium

Add about 1-1.25 pounds per cubic foot of potting soil (around 1.75 cups)

Langbeinite is a great addition to help balance out the rock phosphate. Langbeinite is calcium magnesium sulfate.

Langbeinite has an NPK ratio of 0-0-22. It also helps with magnesium to balance out the calcium from rock phosphate. The sulfur in this mineral is important for making particular amino acids. Because of this, sulfur is necessary to make many enzymes responsible for the production of molecules such as chlorophyll.

It is a common claim that sulfur helps with the production of terpenes or other odors in Cannabis. I have not been able to find any publications on this topic, but I suspect that sulfur is more responsible for odors such as thiols or mercaptans [6] or are used in enzymes responsible for secondary metabolite production.

Add langbeinite at a rate of 1/2 pound per cubic foot of potting mix (about 1/2 cup)

Now that we have amended our potting mixes with plenty of minerals with micronutrients, phosphorous, and potassium, we need to add organic amendments with plenty of Nitrogen and organic matter for the soil microbes to feed on.

Kelp Meal

Add 1/2 cup per cubic foot of potting mix.

Ascophyllum nodosum kelp meal has an NPK ratio of 1-0.1-2. Besides containing organic matter for microbes to feed on and some available plant nutrients, it may contain fatty acids that stimulate plant disease resistance and also may stimulate plant production of growth-promoting phytohormones.

Fish Bone Meal and Fish Meal

Fish bone meal is what it sounds like, ground up fish bones.

It has an NPK ratio of 4-12-0 but it also has about 14% calcium

Add at a rate of 1/4 cup per cubic foot of potting mix

Fish meal has an NPK ratio of 8-6-0. It provides great food for microbes and has a good amount of Nitrogen

Add at a rate of 1/4 cup per cubic foot of potting soil

Neem Seed Meal

Neem seed meal is the ground up byproduct of neem seeds after the cold press extraction of neem oil.

Neem seed meal has an NPK ratio of 6-1-2

Neem seed meal is one of my favorite additions to soil because it acts as an antifeedant and growth cycle disruptor for various insect pests that complete part of their life cycle in the soil such as fungus gnats [19]

Add 1/2 cup per cubic foot of soil mixture

Amazon Links:

Feather Meal and Blood Meal

Feather meal has an NPK ratio of 12-0-0. It is a great source of nitrogen that releases over time through microbe activity

Add feather meal at a rate of 1/4 cup per cubic foot of potting mix

Blood meal also has an NPK ratio of 12-0-0, but the nitrogen from blood meal releases more quickly than the Nitrogen in feather meal.

Add blood meal at a rate of 1/4 cup per cubic foot of potting mix

Crab Meal

Crab meal has an NPK ratio of 4-3-0. It also has a calcium content of 14%

Crab meal also has chitin, similar to insect frass and may help prime plants for disease resistance.

Add 1/2 cup per cubic foot of soil

Crab meal also contains calcium carbonate which can help buffer the soil pH

Alfalfa Meal

Alfalfa meal is a well-rounded organic amendment that has all of the micronutrients and macronutrients required for plant growth. It is a great food source for microbes.

Alfalfa Meal has an NPK ratio of 2.5-0.5-2.5. Add alfalfa meal at a rate of 1 cup per cubic foot of soil.

Oyster Shell

Composed mostly of calcium carbonate, carbonate ions help buffer the soil pH

Oyster shell also improves soil tilth and drainage

It provides slow release calcium

Add 1 cup per cubic foot of potting mix.

For a cheaper potting mix with fewer ingredients, I recommend using the following amendments (not including the microbial amendments mentioned):

Azomite- at previously mentioned application amounts Rock Phosphate- at previously mentioned application amounts Langbeinite- at previously mentioned application amounts Neem Seed Meal (Mostly for the insect control)- Add at 1/2 cup per cubic foot of soil Bio-Live from Down to Earth Amendments that contains: Fish Bone Meal, Fish Meal, Alfalfa Meal, Crab Meal, Shrimp Meal, Langbeinite, and Kelp Meal– Add 1 pound (3.5 cups) per cubic foot of soil mixture Crushed Oyster Shell- For buffering the soil pH. Add 1 cup per cubic foot of potting mix.

After mixing your potting mix with the base, microbial amendments, mineral amendments, and organic amendments together and filling your pots, I recommend top dressing your containers with a thin layer of compost (1/4-1/2 inch) and adding your earthworms to your pots.

If you are growing outdoors and it is after harvest/before planting season, I recommend planting a cover crop mixture to grow over the winter. You can find a variety of mixtures online, but I recommend having a mixture of legumes, brassicaceous plants, and grasses. Following this, I recommend applying a mulch on top that the sprouts can grow through such as a layer of straw about an inch thick and not too dense. After winter, before planting, chop down the cover crop, smother the residue in another layer of compost, sprinkle a small amount (around 1/4 cup per cubic foot of soil) of Bio Live on top, transplant your Cannabis plants, and add another layer of straw mulch on top.



If you are growing indoors or want to plant immediately, You can try an intercropping technique. Transplant your Cannabis plants into the pot. Seed the pot with your cover crop except for a 4 inch radius around your plant (larger radius is better if you have the space) Apply a straw mulch on the soil covering the seeds and the soil under the transplant. Of course, the intercrop will use some of the nutrients in the soil, but there should be a net gain of Nitrogen due to the legumes after a period of time. They should also benefit the soil structure and will support microbes in the soil. Don’t forget to add a straw mulch. If your legumes have been growing for at least 2 months, you can consider chopping them down and smothering plant residues with compost to reduce nutrient competition during flowering. If your vegetative cycle is short (under 2 months), it may be a good idea to thin the legumes but leave them through flower.



In addition to cover crops and compost, it is important to follow a fertilizer regimen. After transplanting my Cannabis plant, I add at least one additive every watering

Seed Sprout Tea- Seed sprout tea has become quite popular recently. Claims are frequently made that these teas provide active amounts of plant growth hormones and digestive enzymes. Unfortunately, most of the claims that I see don’t have citations of where they got this information. Of course, growth hormones have been isolated from various plant seeds and/or sprouts (such as zeatin from corn kernels), and have even been shown to be biologically active at certain concentrations For instance, corn grain extract has been shown to be useful at promoting root growth of banana propagules and potato seed [7, 8]. Seed sprouts also have high levels of enzymes necessary for producing energy from starch reserves in the endosperm, and there is some evidence that enzymes can be stable in soil. The main things that will deactivate enzymes in soils are extreme pH, high temperatures, and protease enzymes from microbes [9, 10]. I only use corn because I can get organic corn kernels from the grocery store for very cheap. I sprout 2 oz. of dry kernels by soaking them for 12 hours in water and then putting them in a jar with a breathable lid after draining the water. It can take up to 2 weeks to get usable sprouts. Next, I blend the sprouts in a couple of cups of water, and dilute it to 2 gallons of water. I also add in 1 tablespoon of kelp meal. I don’t filter out the seed material, but you can if you are worried about saving space in the pot. I add this tea every third watering. Other seeds such as barley or alfalfa may produce sprouts with other beneficial enzymes and hormones.

Compost Tea I outlined my compost tea recipe earlier, I also apply this every third watering, but not at the same time as the seed sprout tea.

Coconut Water Contains mincronutrients including potassium, calcium, and magnesium. Also contains phytohormones such as cytokinins. Add 50 mL per gallon of water I add this every third watering as well, not on the same days as the compost teas or seed sprout teas.

Dry Amendments During Flower, I do 2 top dresses. I add 1/2 cup of Down to Earth’s Rose and Flower mix at first signs of flower and add another 1/2 cup 4 weeks after this. Ingredients: Fish Bone Meal, Blood Meal, Langbeinite, Alfalfa Meal, Seabird Guano, Rock Phosphate, and Kelp Meal I also reapply Bio Live (1/2-3/4 cup per 10 gallons of soil) to the soil surface after transplanting new clones in to the soil. If you are transplanting a new clone or seedling in directly after harvest, do just 1/2 cup. If you grew a cover crop all winter, add up to 1 cup. After harvest, top dress with a small amount of compost and azomite, plant your cover crop, and begin the cycle again.



With all of the additions, it should be obvious that you should start with a large pot with plenty of empty space. I recommend starting with at least 15 gallon fabric pots and filling them up with 10 gallons of starting mix. This will last you many years of no-till growing without ever having to take the soil out of your pots.

I believe the ideal pot size is 20 gallons for indoor growing with 15 gallons of starting mix, but the absolute minimum starting amount is 10 gallons of soil. When you eventually run out of room or your soil has been mostly humified, I do recommend taking the soil out of the pots, adding more rice hulls and minerals, and splitting the soil up in to more pots or taking excess soil and adding it to a garden.

For outdoor growing in pots and very long growing seasons, you benefit by using up to 1,000 gallons of soil, but you can grow smaller plants in as little as 20 gallons. However, I believe too many outdoor growers don’t take advantage of growing directly in-ground. A lot of money can be saved by amending planting holes with aeration, dry amendments, and compost without paying a ton of money for coir and peat based soils. After amending the holes, you can treat the area with no-till practices and keep your holes healthy with cover crops, composts, mulches, and dry amendment top dresses. Plant roots won’t be restricted by volume, water usage is more efficient, and it is better for the environment than relying on shipping in tons of potting mix.

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