How To Make Super Soil For Cannabis Plants

• 1. Cannabis nutrition and soil
• 2. What is super soil?
• 3. Why make super soil?
• 4. Pros
• 5. Cons
• 6. Making your own super soil
• 6. a. Supplies
• 6. b. Step-by-step guide
• 6. c. The composting process
• 7. Using your super soil
• 7. a. How to avoid root burn with super soil?
• 8. Premade super soils for cannabis cultivation
• 9. Cannabis super soil mix - faqs
• 10. 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 feminized seeds need throughout their growth cycle. So if you want to learn how to prepare super soil, read on!

1. Cannabis Nutrition and Soil

Soil. Apart from sunshine and water, it's the most important aspect of a cannabis plant's lifecycle. Soil not only provides the support a plant needs for its root system to thrive, it also acts as the medium to allow the plant to uptake all the vital nutrients that allow the plant to thrive. Before we dive into what exactly a super soil is, let's break down the basic nutrients that every plant feeds off, and how your own homemade mix can help balance these nutrients so your weed plants have exactly what they need. 

So, besides the essential water and sunshine, there are three main nutrients that every cannabis plant needs. Every single fertilizer will have a readout of these three nutrients, and cannabis plants need varying amounts depending on which part of the growth cycle they are currently in.

Nitrogen

This is vital as it is the main component of chlorophyll. Chlorophyll is the compound plants use to capture the energy from sunlight to produce complex sugars during photosynthesis. It also plays a role in amino acid production, which are the building blocks of the proteins a plant needs for basic survival.

Phosphorus

Phosphorus plays a huge role in healthy root development, improves flower formation, and is crucial for the production of ATP and phospholipids which build the cell membranes.

Potassium

(Otherwise known as Potash) Potassium aids in water, nutrient, and carbohydrate movement throughout the tissue of cannabis plants. It also aids photosynthesis, strengthens the cell walls, and regulates C02 uptake.

These are the three main nutrients found in all fertilizers, but there is also a multitude of other micronutrients that are vital for healthy cannabis growth. These include copper, iron, zinc, sulfur, and manganese to name just a few. A super soil takes these micronutrients into account and uses organic matter to add them to the mix.

2. 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.

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.

3. 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.

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.

4. 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 final product with increased yields

Super soil will not only result in a better smell and flavor but will also produce smoother flowers. The majority of growers who use a super soil mix agree that the mix produces the highest quality buds, with superior terpene profiles, maximum resin production, and less harshness from over-fertilization.

• 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.

• Perfect for indoor or outdoor cultivation

Super soil works great no matter the growing environment. Of course, there are some benefits to other growing mediums (which is the reason why not every cultivator uses super soil at all times), but if organic growing is important to you then super soil is the way to go, no question.

• Organic, environmentally-friendly growing method

Most super soil mixes (and the one we highlight in this post) are made from 100% organic materials. No need for costly, harsh, inorganic fertilizers and additives. The results speak for themselves, with a final product that is covered in resin and smells like heaven.

5. 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.

• Mixing the soil takes time and effort

If you are looking for the easiest growing method with minimal effort required on your part, then using super soil might not be the method for you. But, if you are willing to get your hands dirty and take some time to work on your soil before your grow starts you will definitely not regret that little bit of extra work. The results really do speak for themselves.

6. 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.

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.

Supplies

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

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).

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Growing Cannabis: Organic Vs Synthetic / Inorganic Nutrients

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.

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.

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.

7. 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.

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.

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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!”

8. Premade Super Soils for Cannabis Cultivation

There is a huge range of premixed super soils currently available on the market. While these can save you (the grower) a bit of time and effort and are an OK alternative to making your own mix, they are still a mass-produced item. If you are looking for the best results then we suggest following Subpars recipe laid out above. Sure, you do need to do some basic prep and work the soil for a while before it is ready to use, the results are almost guaranteed (as long as you follow the recipe closely). As they say, nothing good comes easy. Cannabis cultivation is a hugely rewarding hobby, so take the time and get your hands grubby. You won't regret it.

9. Cannabis Super Soil Mix - FAQs

What is Super Soil?

Super soil is simply a soil mix that was created specifically with cannabis cultivation in mind. It contains a long list of additives and amendments that work together to create the perfect environment for your cannabis plants.

How do I Use Super Soil?

Super soil can be used in both indoor and outdoor cultivation, and with any size crop. Remember, you will want to let your mix rest for a couple of weeks to a couple of months for the composting process to do its work, but trust us when we say the wait is worth it.

Coco or Super Soil, Which One Should I Use for my Cannabis Crop?

The answer to this question is simple: it depends on your preferences and what you want to achieve. Both coco and soil have their pros and cons, so it really comes down to what you’re looking for in a grow medium, and from the outcome of the grow. If you are wanting to go down the organic route, you will want to stick with soil.  Making your own super soil mix does require a bit of time and patience, but the results speak for themselves.

What is the Best Way to Store Super Soil?

It honestly doesn't matter how you store your super soil once it's mixed up, expect that it should be turned regularly and kept slightly moist at all times. This allows for the beneficial microorganisms time and space to boogie on down and do their thing.

Can I Use my Homemade Compost in my Supersoil Mix?

Yeah, of course. Just keep in mind, you are going to be adding a bunch of different nutrient-rich amendments, so don't go too heavy on the compost.

Are There Any Tips or Tricks for Making Super Soil?

You should always overestimate the amount of soil you will need, at least by a little bit anyway. It's always better to have a little more than less. Making a super soil is a fair bit of work, and the ingredients list is pretty long - so the last thing you want to have to do is make more when planting time comes around. Always lay a nice big tarp or plastic sheet down, and make the super soil on this. It makes cleaning so much easier, and the mixing process is also less work as you can lift the sides of the tarp or sheet to help.

Do I need to pH my water for super soil?

Yes. Well, probably. Let us explain. We always pH our water, no matter the substrate. It's a very easy task that takes no time at all, and it has been proven to benefit cannabis crops in a wide range of ways. Increased yields, fewer nutrient deficiency issues, better root health, etc.

But, there are a bunch of growers out there who don't seem to bother with pH levels when growing in soil. They report great results from just watering directly from the tap,. But when pH regulating water is as simple as a few drops from a bottle, and a 5-minute test, why would you skip it?

Can You Top Dress With Super Soil?

Yep, for sure. This is an effective way of boosting the nutrient density in the pot, but you may be better off just top dressing with a fertilizer designed for that use.

Should I Add Worms to my Super Soil?

For sure! worms are a great addition to any soil mix, super or not.

Can I Just Use Regular Soil Instead of Going to All the Effort of Mixing Up A Super Soil?

You can grow cannabis in regular soil and achieve pretty good results, but if you want your crop to hit its max potential in terms of potency and flavor then we suggest getting that super soil ready! Super soil has been specifically designed with cannabis in mind, and provides everything weed needs to really knock your socks off come harvest time!

Can You Plant Directly Into Super Soil?

No, that's not suggested. Super soil is a potent mix, so it can actually kill seedlings if you aren't careful. Wait until you see the third set of leaves appear, and then transplant them into your super soil mix.

What Are Some Common Problems with Super Soil?

Planting seedlings is a big one. beginner growers often think that to get the best results, the crop has to be exposed to the most nutrients possible from the very start. This couldn't be further from the case, especially with autoflowering plants. Seedlings like low nutrient levels.

You need to keep your super soil well-oxygenated and moist while it is 'cooking'. We suggest giving it a turn every single day, but that might be a little overboard. Better safe than sorry though, right?

Can Super Soil be Used in Conjunction With Other Types of Soil?

Super soil can actually be used in conjunction with other types of soil, to give your plants the best of both worlds. For example, you could use a mix of coco coir and perlite for the majority of your potting mix, and then add a layer as top fertilizer during the third week of veg.

Do You Need to Add Nutrients to Super Soil?

Nope, once the mix has been made, and made with all the ingredients listed above, it will contain everything the plant needs for its full life cycle. Just water with pH regulated eater and you should be totally fine!

10. 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!

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 April 6, 2022.