How To Make Super Soil For Cannabis Plants

Super soil allows you to reutilize the soil and grow cannabis without having to worry about pH or adding extra nutrients
30 July 2021
7 min read
How To Make Super Soil For Cannabis Plants

  • 1. What is super soil?
  • 2. Why make super soil?
  • 3. Pros
  • 4. Cons
  • 5. Making your own super soil
  • 5. a. Supplies
  • 5. b. Step-by-step guide
  • 5. c. The composting process
  • 6. Using your super soil
  • 6. a. How to avoid root burn with super soil?
  • 7. In conclusion

Super soil became widely known after SubCool, a legend in the cannabis world released his recipe intended to be used to grow cannabis. This type of soil refers to soil that has been prepared to contain all the nutrients a plant needs throughout its growth cycle. So if you want to learn how to prepare super soil, read on!

1. What is super soil?

Super soil can be made with organic homemade or store-bought products and is designed to contain all the nutrients a cannabis plant needs from seed to harvest.

The soil is prepared with 100% organic components which contain living microorganisms that help create an ecosystem similar to the one we find in nature.


Super soil for cannabis plants: what is super soil

Super soil can be used outdoors and indoors.

Just like in nature and other methods such as composting, for example, super soil consists of creating and maintaining the beneficial microorganisms that work together in the soil. It’s a natural way of increasing the quality of your harvest without using synthetic fertilizers or pesticides.

2. Why make super soil?

There are several benefits when growing in super soil, by using the correct recipe you can create a 100% organic medium that is almost identical to the soil where cannabis plants thrive in nature.

Growing in super soil also facilitates the process of growing cannabis, when done correctly you will only need to water, there won’t be a need to check pH (after checking the pH of the water source), add more nutrients or do anything at all other than checking your plants and making sure they’re growing as they should.


Super soil for cannabis plants: why make super soil

Plants grown in super soil are maintained with plain water, you should add nutrients only if you see your plants are hungry.

Not only that, as long as you keep the microorganisms alive and maintain your super soil properly you can reutilize it indefinitely, and as time passes it will be richer and consequently result in better harvests after each cycle.

3. Pros

  • Easy to use

Super soil is super easy to use once you’ve made it because it’s made from organic sources so you don’t need to check pH (if your water source is “clean”) or add extra nutrients.

  • Better quality

Super soil will not only result in a better smell and flavor but will also produce smoother flowers.

  • No need to flush

Since you’re not using synthetic nutrients and your plant chooses which and when to absorb nutrients, there won’t be a nutrient build-up.


Super soil for cannabis plants: pros and cons

Pros and cons of super soil.

4. Cons

  • Can be expensive to get started

Depending on where you live, it can be hard to find the right ingredients. You should use high-quality natural ingredients if you expect good results.

  • Takes time

Making your own super soil from scratch can take from 30-60 days before it’s ready, even though it takes a couple of months the results are definitely worth it.

  • Slightly slower growth

Because you’re not feeding the roots directly you may notice a slightly slower growth rate, now this shouldn’t be a problem at all unless you have a deadline or want to harvest as fast as possible.

5. Making your own super soil

Before making your own super soil for cannabis plants,  make sure you have all the ingredients (you cannot add them later on when the soil is ready) and you have enough space to mix them, depending on the amount of soil you’re making it’s better to do it outside.


super soil for cannabis plants: supplies

Supplies needed to make the best quality super soil.

A very important thing is that you need a container or tarp because the heat it will emit is needed for the composting process to work properly.


This recipe is based on SubCool’s cannabis super soil recipe, you can easily find alternatives and substitutes to some ingredients but this one has been used by a lot of growers with great success. So, in order to prepare super soil, you'll need.

SubCool's Cannabis Super Soil Mix


Organic soil (with coco fiber and mycorrhizae)

Organic worm castings2.2kg
Bone meal200g
Blood meal200g
Bat guano (for flowering)200g
Rock phosphate150g
Epsom salts100g
Azomite 65g
 Humic acid 10g
 Perlite (optional) 1kg


Note that the original recipe was designed to make 100 gallons of soil but we've adjusted it for you to prepare super soil for 1-gallon pots (around 4kg).

Step-by-step guide

Have in mind that you can just throw everything in and mix it but following the step-by-step guide you guarantee the soil is mixed properly and avoid having to mix it over and over. 

Step 1

Spread 1kg of soil on the tarp, if it doesn’t contain coco fiber or mycorrhizae, you should add it now. You’ll need approximately 45g of mycorrhizae and 1kg of coco fiber.

Step 2

Add the bone meal and mix well.


super soil for cannabis plants: organic amendments

Super soil should be done with 100% organic amendments.

Step 3 

Sprinkle the azomite and dolomite over the entire pile and add another 1kg of soil on top.

Step 4 

Add half of the worm castings and perlite (if you opted for using) and cover with 1kg of soil.

Step 5

Mix in the other half of the worm castings along with the blood meal, bat guano, Epsom salt, rock phosphate, humic acid and top it with the last 1kg of soil then mix thoroughly.

The composting process

Over the next 7-10 days continue to mix the soil at least once a day until you don’t see any more spots where the ingredients are not mixed, when the 7-10 days have passed and the soil is well mixed, store it in a container (like a garbage can) or a tarp. 

You need to keep the soil in a closed container so it doesn’t dry up fast. The soil needs to be constantly moist but not completely wet, moisture is essential to continue the composting process and if it dries up the whole process will stop.


super soil for cannabis plants: mix soil

Your super soil should be moist and well-mixed during the composting process.

During the next 30-60 days, you will have to keep the soil mix in a sunny place, during this period the super soil will start to emit heat which is a sign that microorganisms are effectively breaking down the nutrients (composting process) and the process is going as it should.

After the composting period has passed, your super soil is ready to be used.

Super soil tips

  • If you want to accelerate the process you can also add worms to the mix, they will help aerate the soil and will help accelerate the process.
  • Bugs love organic matter and rich soil, the soil mix you just made is the perfect place for bugs so remember to check for bugs if your container or tarp is completely enclosed.
  • The more you let your super soil compost the more concentrated it will be, have that in mind when you're going to use it.

6. Using your super soil

Have in mind that this super soil is super concentrated and can burn your plants so you have to mix 1 part of super soil to 3 parts of normal organic soil like the one you used in the super soil mix, so for example, if your pot holds 1kg of medium you’ll want to add 250g of the super soil in the bottom of the pot and then use 750g of regular soil on top.

If you think your plant needs more nutrients, you can add super soil as a slow-release top feed which will release nutrients when watering.


super soil for cannabis plants: how to use super soil

Super soil can be too strong for plants, make sure you mix it properly to avoid nute burn.

Also, there’s no need to check or adjust the pH level of the soil or water you’re using as long as it ranges from 6-7 and doesn’t contain more than 400PPM of trace elements. If your tap water isn’t good enough you can filter it first and once the water source is good there’s no need to check the pH again unless you see signs of deficiencies.

How To Avoid Root Burn With Super Soil?

Cannabis super soil contains everything your cannabis plants need from seed to harvest. However, depending on the nutrient content, it may be too strong for seedlings and can end up causing root burn. So if you’re planning on growing in cannabis plants in super soil, it’s recommended you either germinate the seeds in unfertilized soil and transplant them to a bigger pot with super soil once they’re around 2 - 3 weeks old. 

Another good option is to fill the bottom ⅔ with super soil and the top ⅓ with the unfertilized substrate, this way your plant only reaches the super soil once it’s big enough but it isn’t an exact science because root development and plant growth depend on strain to strain and the growing conditions.

For autoflowering cannabis plants that are more sensitive to transplanting, you can prevent root burn by filling the bottom half of a 12 L pot with super soil, then placing a 3 - 5 L pot in the middle, and continue filling the 12 L pot with super soil. After you remove the smaller pot, you’ll be left with a hole the size of the pot, so you just fill it with unfertilized substrate and germinate the seed right in the middle. Doing this prevents root burn because your autoflowers will only reach the super soil once the roots have grown enough which is when autoflowers start needing nutrients.

“Remember that you only need to water super soil, there’s no need to add nutrients unless your plants are hungry!”

7. In conclusion

If you're looking for cannabis soil in the UK or anywhere else where you cannot find organic super soil, this recipe will help you prepare super soil. Super soil for marijuana is a great way to grow cannabis plants cheap and effectively, even though it takes longer than just mixing bottle nutrients, you will see the difference in the smell and flavor of your flowers so make sure you grow strains with strong terpene profiles such as our Strawberry Banana Auto!

Strawberry Banana Auto
4 out of 5
Delivery was a bit slow.... other than that I'm satisfied with the buying process. EVen got some freebies with my order which is always nice.
Verified customer
Reviewed 13 April 2021

Feel free to help fellow growers prepare super soil by leaving tips or your own super soil recipe in the comment section below!


External References:

  1. Organic soil amendments for sustainable agriculture - Hue, Nguyen & Silva, J.A. (2000). 
  2. Super Soil Systems - Gary Gereffi and Marcy Lowe (2008).
  3. Building Soil Organic Matter with Organic Amendments - Leslie Cooperband (2002).


This post was most recently updated on July 28, 2021.

30 July 2021