What is the best soil for growing weed?

If you’ve thought about growing, you’ve probably already thought about the best soil for cannabis.

You likely didn’t give it that much thought, though, because who takes time to think about soil?

Well, the soil that you grow your marijuana in is very important, so if you want to grow the best weed possible, you should pay some attention to it.

This guide will cover everything you need to know about the common growing medium.

The basics of using soil for marijuana grows

Plants typically need three things to survive: water, light, and soil.

Soil may seem obvious, but nowadays, with soil alternatives and hydroponic growing, even that is optional.

However, for most growers, especially those who are new to growing marijuana, growing in soil is the best option.

Soil growing (instead of growing in nutrient-infused water) is one of the easiest and most familiar methods of growing.

It’s also one of the most natural ways to grow any plant.

Using soil for growing marijuana
Soil for marijuana plants

Plus, attempting to grow hydroponically the first time you are growing marijuana is almost guaranteed to be a recipe for disaster.

Soil is simply the natural way to grow, but it is still important to start with a good quality soil.

After all, it provides the plant’s nutrients and helps the plant form stable roots.

High-quality soil is especially important for outdoor plants who could face potentially harsh winds and other environmental conditions.

Why grow marijuana in soil?

Great soil can help your plants thrive, so it is essential to first understand what soil is.

It is definitely more than dirt.

Advantages of using soil

The soil is the most natural medium for growing almost all kinds of plants. It means that most people already are familiar with or have experience in doing it.

In effect, it is easier and less stressful to use than other modes of planting, which requires a learning curve.

Another advantage is its simplicity in making it work. Just watering the soil is enough for most plants to grow.

Also, the supplies needed are few compared to using other costlier mediums.

Natural soils are made up of mineral particles, air, organic matter, water and biological organisms.

Growing marijuana plants in soil
Growing cannabis in soil

Disadvantages of using soil

Since soil is an organic material, it is natural for bugs to live in it.

Therefore, the plants are more prone to suffer from pest infestations.

There is also the issue of slower growth.

In contrast, marijuana grown using hydroponics enjoys explosive growth due to faster and more efficient nutrient absorption.


Nearly 25% of soil is air that exists in a gaseous phase –not quite liquid or solid.


Water is known as soil solution, a liquid made of water, and ions from dissolved salts, and chemicals.

These ions are unable to attach to minerals in the soil.

Water also makes up nearly 25% of soil. The mineral particles in soil consist of sand, clay, and silt.

These inorganic particles can significantly impact a soil’s quality.


These tiny fragments of rocks and hard minerals (such as quartz) do not carry any nutrients, meaning large amounts of it in your soil is a bad thing.

Soil with lots of sand is arid;

however, small to moderate amounts can improve drainage and aeration as well as increase tilling quality.


This mixture of sand and minerals has some nutrients, but not many.


It is is beneficial for soil, as it can include the important nutrients of K, Ca, Mg and Fe- making soil fertile.

Clay is aluminum-silicate and has negatively charged ions that attract these nutrients to it.

However, if there is too much clay, it will be hard to till the soil, and there will also be poor drainage.

Soil also includes a variety of organic matter and substances such as:

  • Decomposing plant and animal particles
  • Organisms and microorganisms living in the soil
  • Substances produced by roots and microorganisms

These exist in smaller amounts, typically around 5%. Although there isn’t much organic matter in soil, its presence highly influences its quality and the eventual yield of your plants.

The particles and substances are also known as humus, whereas organisms may include earthworms and other beneficial creatures.

How to recognize the best soil for cannabis plants

Now that you understand what soil is, it is much easier to recognize good soil when you see it.

Marijuana soil has some specific requirements, so unless you are buying soil that is specifically designed for cannabis, you’ll want to learn to pay attention to certain things.

Good soil will have the correct texture, drainage ability and water retention for marijuana. It will look dark and rich, with a loose texture that isn’t muddy. Check out the video below to learn more!

Good marijuana soil also drains well – you should be able to pour water on it and have it drain out within a few seconds.

The soil should retain enough water for the plant to thrive, as the roots need that water, but it shouldn’t be so much that the roots cannot get enough oxygen either.

This is why both proper drainage and water retention are essential aspects of good soil.

choosing the best soil for cannabis
Recognizing good soil for growing cannabis

Good soil also has good ingredients. Of course, soils that include some form of organic matter (humus) are great for marijuana because they provide plenty of nutrients.

Traits of quality cannabis soil

Some examples of organic matter to look for in a good cannabis soil include:

  • Earthworm castings
  • Bat Guano
  • Blood, fish, or bone meal
  • Kelp
  • Coco Coir
  • Mycorrhizae
  • Perlite
  • Pumice
  • Sandy Loam
  • Dolomite lime

If you purchase good cannabis soil that has any of these ingredients in it, there’s a good chance it might provide great nutrition for your plants.

You’ll still want to make sure that it has the right nutrients for your plant’s particular stage in its life cycle though.

BTW growing marijuana plants in soil can get you high yields. Download my free marijuana grow bible and and get a step by step guide!

Choosing the best soil for your marijuana plants

With an understanding of what you are looking for, you can now start to select the right soil for your plants.

The first thing to remember is that soil is highly dependent on the stage of life that your plant is in.

While it is still sprouting, it is best to use peat plugs or something similar to that.

These ready-made blocks of soil provide everything that a budding seed needs to make its way into the world.

If you can’t find, (or don’t want to use) peat plugs, an organic potting soil will also work.

Organic soils will not have any added ‘slow-release’ chemicals, something you’ll want to avoid when growing marijuana.

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While potting soils do not have the right type of nutrients to support a growing marijuana plant, they will have enough to support a seedling for its first couple of weeks.

After that point, you’ll want to supplement with nutrients that are specifically designed for marijuana plants – especially once you reach the flowering stage.

Another reason why it is okay to use potting soil (at least at first) is because you’re likely going to end up moving your plants after they are about a month old anyway.

The roots will be too big for their first home, and you should place them in a bigger container or move them outdoors.

That is the perfect time to switch out your soil for something more suitable.

If you used peat plugs, you can simply add the plugs to local dirt or grass mulch to make a suitable soil outdoors.

Not only does this provide a better texture over the natural earth, but it also offers ample room for young roots to move around and increases the nutrient value in the soil.

Choosing the perfect soil for growing marijuana
Choosing the perfect soil for cannabis

You can also move your seedlings into either sterilized potting compost or a “living soil.”

If you opt for sterilized soil, it should include some form of amendment (such as perlite), that makes up at least 20% of the soil.

This additive will help increase the amount of air present in the soil, which helps marijuana plants grow faster.

Living soils, on the other hand, are composted soils.

They are useful because they include microorganisms that create an ecosystem similar to the best natural scenario.

The roots directly absorb the nutrients produced from these organisms, and the results are often noticeable in the flavor and scent of the harvest.

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Living soils rarely require added nutrients since the microorganisms provide all the nutrients that your plant will need.

You’ll want to repot your plants just before flowering if you use this type of soil.

What to look for in store-bought cannabis soil

  • Avoid time-released chemicals. They release nutrients throughout the plant’s life.
    During the flowering stage, your plants will need different nutrients, and you’ll have a hard time adjusting the soil to fit the changing needs of your plant.
  • Look for dark, rich soil. Pale, crumbly or sandy soil probably has too much sand or the wrong moisture levels. It probably also does not have the right nutrient levels.
  • Touch it if you can. Good soil should form into a ball when you squeeze it and fall apart when you open your hand. It should be fluffy, light and airy.

You can also simply make your own soil – especially if you live near an organic farm.

Cow and pig excrement that has rested for at least a year is wonderful soil.

In fact, it is often sold as high-quality fertilizer since it has most of the nutrients that plants require.

You could even mix it 50-50 with sand and produce amazing yields.

Another option is topsoil from excavation companies.

Growing marijuana plants outdoors in a soil
Growing cannabis outdoors in a soil

How to make average soil better quality

If you’re starting with sterilized potting soil, mediocre topsoil or any other soil that you aren’t particularly happy with, you can add things to it to make it better.

Some of the best cannabis soil amendments are easy to obtain and make a big difference on your own soil.

Try some of the following “added ingredients” to make your cannabis soil even better:


Add perlite to any of your own soil that doesn’t already have it. These light airy ‘rocks’ will add oxygen and increase its drainage ability.

Add perlite to soil for better marijuana growth
Add perlite to soil

Perlite can be up to 40% of the total volume depending on your needs.

Use more of it if you plan to use a lot of nutrients and want to protect against nutrient burn.

Coco coir

Coconut makes everything better – at least when it comes to soil. Coco coir is made from the husks of coconuts.

Adding coco coir to the soil for growing cannabis
Adding coco coir to the soil

It improves water retention without making the soil heavy, decreases the chance of overwatering and helps with root development.

Coco coir is a great soil alternative, but if added to existing soil keep it under 30%.


If your soil is too heavy, you can add this substance to lighten it up.

It also improves water retention, just like perlite, but it does a better job of it.

Vermiculite for growing cannabis

Unlike perlite, it doesn’t do a good job of improving aeration and drainage, but if you need help with that, you can add them both.

Just choose which one you need more, and only add a little of the other.

The combination of vermiculite and perlite should not be more than 50% of your soil.

Worm casting

Worms excrete nutrients that cannabis plants love, and thankfully, you can buy this worm poop and add it to your soil.

Worm castings improve the texture of your soil, moisture retention, and drainage.

Worm castings for cannabis
Worm castings

If you have this additive, you will not need to add anything else.

You can safely make worm castings up to 30% of your soil.

Potting soil

Choose Good Potting Soil
Choose Good Potting Soil

Sandy soil

Sandy soil outdoor cannabis growing

Creating a super soil

If you’re feeling creative, you can make a special kind of homemade soil called super soil.

Super soil has added slow-release nutrients and then it is composted for months.

Also read Best compost and fertilizer for outdoor marijuana plants

By composting it, the soil becomes a living soil in that it has microorganisms, which are extremely beneficial for the root structure of your plants.

Roots feed these microorganisms, and in exchange, they feed your plants.

With super soil, you’ll never need to worry about nutrients or measuring the pH because nature does all the work for you.

Super soil for cannabis
Super soil

Super soil has some obvious benefits, such as a better taste and smell in your harvest, but there are a few drawbacks as well.

This amended soil is expensive and time-consuming to make, so it’s not economical for the everyday grower unless you are growing other things as well.

It also slows the growth of your plants (when compared to liquid nutrients) because your plant needs time to absorb all those goodies provided by the microorganisms.

Nutrients in a liquid form are much easier for plants to absorb.

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If you decide to create super soil, however, you are creating the optimal environment for your plants, whether they are grown indoors or out. All you need to do is remember to water.

Your growing medium can either help or hinder your plants, so you’ll want to choose the best one for your situation.

If soil is your medium of choice, that means ensuring it has the right qualities for optimal growth.

With the right soil, your level of effort significantly decreases as your quality of bud increases. That’s a nice slope!

How to make super soil for marijuana

Ever since the secret about Super Soil came out, growers are using it to produce top-shelf organic buds.

While it is ideal for large producers who aim for bigger yields, small-time home growers can also try making it.

In 3 steps, here is what we need to prepare and do to make our own Super Soil.

Step 1. Base

Prepare high-quality organic potting mix. The recommended amount is 8 x 30 pounds.

Step 2. Additives

Here are the things to combine with the potting mix to create a super-charged soil.

2.1. Azomite

This material comes from volcanic rock and contains over 70 minerals and trace elements.

Since it contains gold, copper, silver, and calcium, to name a few, its basic use is to remineralize the soil.

Having abundant, diverse minerals is a good way to ensure the health of the plants.

The recommended amount is 1/2 cup.

Azomite for cannabis

2.2. Bat Guano

Bat feces is a rich source of nitrogen.

Also, it comes with an outstanding balance of other minerals such as phosphorous and potassium.

Bat Guano for cannabis
Bat Guano

Most importantly, it does not leave any metallic taste on the buds like other additives.

The recommended amount is 5 pounds.

2.3. Blood Meal

This additive is not vegan-friendly, but it is an excellent source of nitrogen.

Made from the dried blood of mostly cows, it seems like an unpleasant idea for fertilizer.

Blood Meal for marijuana plants
Blood Meal

But it is a popular gardening product that increases the growth of cannabis during the vegetative phase.

The recommended amount is 5 pounds.

2.4. Bone Meal

During the flowering phase, the fine powder of animal bones provides phosphorous for more and bigger blooms.

Bone Meal for marijuana
Bone Meal

Just be cautious of this ingredient if there are vegans who use the buds.

The recommended amount is 5 pounds.

2.5. Dolomite or Sweet Lime

Rich in calcium and magnesium, this mineral rock prevents organic nutrients from escaping the soil.

It also keeps the pH level from being too acidic.

The recommended amount is 1 cup.

Dolomite for marijuana growing in soil

2.6. Epsom Salt

Magnesium aids in nutrient absorption. It also happens that Epsom Salt is rich in this mineral.

Thus, we use it to avoid deficiency.

Epsom Salt for cannabis growing
Epsom Salt

But be careful in adding it. As with all other additives, too much of a good thing can be bad.

The recommended amount is 3/4 cup.

Know how to perfectly time your harvest so you can maximize your yield. Download our free mini harvesting guide.

2.7. Kelp or Humid Acid

Fungi are important in the soil’s pH level, so we use kelp or Humid Acid to feed them.

Humid Acid for cannabis growing
Humid Acid

The recommended amount is two tablespoons for humic acid and 1/4 cup kelp meal for every five gallons of the material.

2.8. Rock Phosphate

Another natural fertilizer that works by upping the levels of phosphorous in the soil is Rock Phosphate.

For best result, bone meal and Azomite is added to it.

rock phosphate for growing marijuana
Rock Phosphate

Aside from acting as a pest-repellent, it is also the fertilizer of choice for marijuana in the flowering stage.

As a result, the flowers are usually big and vibrant. Also, the buds have a richer flavor.

The recommended amount is 3 pounds.

2.9. Worm castings

Because it is nutritious, the more worms, the better for the plants. The worm’s poop is known as the “worm cast.”

According to research, it is heavy in micronutrients as well as macronutrients. As such, it plays a vital role in soil fertility and plant growth as well.

Worm casting for marijuana plants
Worm casting

The recommended amount is 25 to 50 pounds.

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725894/

Step 3. Mix them up

Once all the ingredients are available and ready, mix them. Usually, it takes a full week of mixing it using a shovel.

Then, we store it once it has all come together as one color.

During storage, the composting process begins. In a month or two, it should be ready for use.

Need weed seeds to plant in soil? Shop seeds of your favorite strains in our shop.

FAQs about growing marijuana in soil

What nutrients can I add to my soil to improve it?

You need to add materials that help the seed grow in a healthy condition – which means adequate nutrients and water for germination. Using peat plugs will be a lot easier, but potting mix and composted manure are also good alternatives.

What is the best soil for autoflowers?

A new type of soil known as Super Soil is famous among cannabis growers nowadays. Created by Subcool, this medium is by far the best soil for growing autoflowers and cannabis in general because it has the right amount of nutrients and acid balance. As such, growers only need to water the plants. Just be reminded not to use this soil to seedlings as it may burn them.

How do you make homemade Supersoil?

You can make your own supersoil by combining high-quality organic potting mix with additives like azomite, bat guano, bloodmeal, dolomite, epsom salt, kelp or humid acid, rock phosphate and worm castings. Then, mix them up using a shovel for about a week. Store it once it has all come together as one color. It is during storage that the composting process begins. It should be ready for use in a month or two.

Avatar for Robert Bergman

Robert Bergman


Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations ... See profile

24 comments on “What is the best soil for growing weed?”

  1. What is meant in Step 1 Base of Super Soil

    Prepare high-quality organic potting mix. The recommended amount is 8 x 30 pounds.

    8 x 30 pounds – is that 240 pounds of potting mix?

    • Hi John,

      Thanks for your comment. This assuming you’re mixing for 8 pots. Each of these 30 pounds would fill out about a 4 gallon pot!

      I hope this clears it up.


  2. Hi there,

    Thanks so much for the kind words, we really appreciate that. And we are happy to hear this!

    Happy growing and let us know if there’s anything we can do for you, of course.

  3. I’m starting zskittles auto should I go from seed sprout to final pot or start with smaller pots and transplant to final pot

    • Transplant once. After seeding is 6-8 inches transplant into 3-5 gallon grow bags. Preferably the wovan bags NOT PLASTIC.

  4. I’ve just started a grow about 10days into it and the knowledge you share is very easy to grasp as a Novice.Im using Cana tera professional soil and the 3 little lady’s are doing well as can be just given them tap until they start the veg state and then introducing them bio biz neutrants a grow a bloom and top max.It can get a bit confusing for me regarding reading the feed charts so I’m not giving them the recommended dosage maybe half as I don’t want to overload the plants.Thank you again for making your information simple as possible for us new to the growing indoors or outdoors .I’m in Scotland so the weather is not good enough for outside growing due to the unpredictable weather

  5. I have been using fox farm soil really good results in first grown starting second grown know going to use the same

    • I am a beginner and i Received a grow tent for christmas. I am from Boston so I will be starting inside , what is the best soil to use. Farm fresh?

  6. Thank you very much for the helpful information about the soil need to grow marijuans . I want to grow marijuana for health readons.

  7. Hi, i soaked seeds for 2 days. Looked ilke they were star to open. I put in seesing soil. It’s been 2 weeks ! Nada????? Any th

  8. I’m basing all desions on what the strain likes. That’s my ? I’m new but have a good basement and quality ebb and flow six pot. I’m thinking auto flowering bc I don’t know wtf I’m doing and that helps. I enjoy kush and thought sample of 3 kush or 20 White widow beginner level. I want wieght to. Based on that ramble what say you? Afgan kush or begin pack? Or other…

  9. Matt. Soil recipes are abundant across the W3. I suggest you join our support forum and discuss soil building with our many expert members and staff at: support.ilovegrowingmarijuana.com

    Happy growing