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Guide To Using The Best Soil to Grow Cannabis

Added 12 June 2022

One of the biggest decisions before growing your cannabis plant is choosing the growing medium. And soil is the most popular growing medium for most growers. This is because it has various advantages and is easy to work with.

However, growing cannabis in soil is not as simple as tossing a seed in your backyard. You need to choose the best soil for your plant that has adequate nutrients for optimal growth. In this article, learn all about the best soil to grow cannabis.

Breakdown of Good Soil for Cannabis Plants

manure and worms

Your cannabis plant requires three things to thrive — water, light, and soil. Among the three, soil can be a bit confusing for many new growers. So, here are the basics of soil for cannabis growers.

Soil is the traditional approach, in case you're looking in that direction. You don’t have to worry about it altering your plant’s flavor or scent, and it will not tamper with the plant’s natural growth.

While there are alternatives to soil like coco coir or a hydroponic setup, many growers still prefer using soil. First off, growing cannabis in soil is quite straightforward, and if you have a backyard, you may already be familiar with it. Plus, compared to other mediums, it's pretty inexpensive.

Benefits of Growing Cannabis in Soil

benefits of growing cannabis in soil

If you can get your hands on high-quality soil, you will grow a healthy, vigorous cannabis plant because it offers various benefits over other grow mediums, such as the following:

User Friendly

Almost all the plants in the world grow in soil, making it very easy to grow cannabis plants. And since the dawn of civilization, we have been growing plants in soil, so there is a horde of information on the internet about using soil to grow plants. 

Natural Growing Medium

High-quality soil is teeming with microbes and other organisms necessary for plants to thrive. These microbes feed on the soil and the plants, in turn, feed on them, making it a natural ecosystem. 

Easiest Medium to Work With

Beginner growers can find it very easy to set up their cannabis garden with soil as the growing medium since it's easy to use. Soil is less stressful than other grow mediums, like hydroponics or aeroponics, and does not require a learning curve either.

Enough for Your Plant

If you choose the right kind of soil, it is more than enough for a healthy plant. You no longer have to tinker with the nutrient solution in most cases, unless you want to, because the soil contains all the essential nutrients and minerals your plant needs.

Plus, if the soil is not as fertile as you'd expected, you can always use some easy techniques to improve its condition.

Fewer Supplies Needed

Soil-based plants only need good soil to grow. And sometimes, a container. And soil is cheap, and often free, to come by. So you don’t have to worry about investing money into acquiring a lot of growing supplies. And if you have a garden of your own, you won’t even need a container.

Drawbacks of Using Soil for Cannabis

drawbacks of growing cannabis in soil

But not everything is rainbows and sunshine with soil. It does have some drawbacks that can make it bad for your plant, such as the following:

Pests Love Soil

Pests love making good soil their home because it has the right environment for them. This makes your plant more prone to pest infestations. And while most pests are harmless, some pests can spell disaster for your plant. 

Slower Growth, Sometimes

With a soil-based setup, you don’t have as much control over how your plant grows. So, you can’t expect the plant to grow explosively like it would in an aeroponics system. You just need to let the plant grow at its own natural pace.

How to Recognize the Best Soil for Cannabis?

best soil to grow cannabis

If you are out in a gardening store for soil, you need to learn how to identify good soil from bad. And this process is quite easy. 

This is essential if you are buying regular gardening soil because it may not contain all the nutrients required for cannabis. However, if you purchase cannabis-specific soil, you don’t need to worry so much because it already contains everything essential for your plant.

And high-quality soil is unlike regular soil — the latter can hamper your plant’s growth and yield. So, you need high-quality soil for your plant, and here are a few considerations that come into play for the same.


Soil comes in all sorts of consistency — some are loose enough to aid aeration to the roots and others are dense enough to inhibit airflow. And the plant’s roots need air to breathe and grow properly.

So, the high-quality soil that you choose for your cannabis must have enough aeration so that the roots can breathe easily and grow vigorously. This will in turn result in explosive plant growth and health.

Water Retention

Another crucial consideration is water retention — how much water can the soil hold? Water contains ions in the form of dissolved salts and minerals, which fail to attach to the minerals within the soil. So, the roots cannot absorb them if the water drains out too fast.

On the contrary, if the soil holds water for too long, it may drown the roots and cause all kinds of problems like a nutrient lockout, root rot or slime, or even stunted growth.

The soil you choose must have enough water retention to hold some amount of water but not enough to drown the roots. The water should drain relatively fast but only in a certain amount.

Soil Density

When roots get enough water, air, and nutrients, they will expand their network tremendously. However, they don’t like to work too hard. So, if the soil is too compact, the roots may not grow properly, which is not good for your plant’s health.

You need to ensure that the soil you choose is not too dense, allowing for easy root expansion. An easy way to test this is if you can stick a finger into the soil with minimal pressure, the soil is good for your plant.

You can also compare the weight of various soil bags — the heavier the bag, the denser the soil is within.

pH Levels

If you know anything about cannabis, you already know how important pH is. Cannabis likes the pH to be slightly acidic. However, if the pH is too acidic or alkaline, it can inhibit the roots from absorbing the nutrients properly, causing nutrient deficiencies.

An ideal soil should have a pH of 6.0 to 7.0. You can use your pH meter to check your soil’s pH both before and after you plant your cannabis. Many minerals can also alter the pH, so it is advised to test the pH regularly. To check the soil's pH, you can use the run-off water or send the soil to a lab to get accurate results. 

Varieties of Soil: Sandy, Clay, or Silt

cannabis plant growing in soil

Lastly, you need to understand what kind of soil you have at hand, whether it is sandy, clay, or silt. Generally, the soil is a combination of these, but here is what each of these varieties means for you.

1. Sandy Soil

Sandy soil is majorly made of hard minerals or tiny rocks, which do not contain any nutrients. In large amounts, sandy soil is bad because it is arid and won’t benefit your plant in any way.

However, in small quantities, sandy soil can be good for your plant because it aids in aeration and water drainage.

2. Silt

On the other hand, silt is a mixture of minerals and sand, and it may contain some nutrients. While it does not contain all the essential nutrients your plant needs, it can still aid your plant in small to moderate amounts, only if it is mixed with high-quality soil.

3. Clay

Clay is quite beneficial for your plant as it includes various nutrients like calcium, magnesium, iron, and potassium, which improve the medium’s fertility. Clay is made of aluminum silicate, which can hold these nutrients in place.

But you need to add clay in a moderate amount only, or it may turn the soil too hard and cause poor aeration and drainage.

4. Other Organic Matter and Substances

bat guano

Soil also contains other substances and organic matter, though in varying quantities. These matters include decomposing animal and plant matter, living organisms, and substances produced by the organisms and roots (known as humus).

These matters typically make up only 5% of the soil, but they significantly influence the medium’s quality and plant’s health. 

It must also contain the right nutrients, like humus and microorganisms; some of the types of humus you should check for include:

  • Earthworm casting
  • Bat guano
  • Blood, bone, or fish meal
  • Kelp
  • Coco coir or perlite
  • Pumice
  • Sandy loam
  • Dolomite 

When soil meets these criteria, all your worries can rest. It can easily handle and help you grow a big, bushy plant with plentiful buds.

How to Get High-Quality Soil for Cannabis

earthworm in soil

Armed with the right knowledge, you can now start selecting the best soil for your plant. But remember, the type of soil you use depends on your plant’s growth stages since cannabis requires different nutrients at each stage of its growth.

So, when you are planting a seed or a seedling, the best type of soil is peat plugs or similar. They are ready-made soil blocks containing all the right nutrients and conditions for the seeds to sprout and grow properly. You can plant your seeds in the block and wait for germination. 

If you cannot source peat plugs or prefer not to use them, you can also use organic potting soil for seedlings. Organic soil is devoid of any slow-release chemicals, which you should avoid for a young seedling. 

However, potting soils or peat plugs do not contain the right nutrients to support a vegetative cannabis plant. So, once your plant has grown enough, you will have to supplement the medium with cannabis-specific nutrients, especially during the flowering stage. 

If you're using potting soil, you will most likely have to transplant your cannabis after a month anyway, so you don’t have to worry about supplementing nutrients just yet. This is because the roots of the plant will have outgrown the small container and will need a bigger place to grow into.

Once your plant has grown enough, you can move it into a bigger container with better soil. Here, you have a few soil options that you can consider.

Sterilized Soil

Sterilized soil is a terrific option because sterilization requires heat to eliminate any microbes or organic matter within it. If you live in an area with moist conditions or pest problems, this is a good option to consider. 

Just remember that you would have to make up for the lack of microbes and dead organic matter by supplementing the soil with other materials. Also, you would have to add some form of soil amendment, like perlite, to the soil by at least 20% to improve aeration within.

Living Soil or Compost Soil

Living soil or compost soil is the same thing — it is the opposite of sterilized soil as it contains various microorganisms and organic matter, creating a rich ecosystem for your plant to thrive in. 

The benefit of compost soil is that the microorganisms produce various nutrients for the roots, resulting in much better results with a noticeable difference in the flavor profile of the buds.

Plus, you don’t need to worry about supplementing nutrients in most cases because all the nutrients are already there.

Homemade Soil

You don’t even need to visit a gardening store for the best soil; instead, you can simply make your soil with tremendous benefits for your plant. The two most popular homemade soil for cannabis are loam and super soil, which are later discussed in the article.

These soils primarily allow you to save money but do require some elbow grease and time. But they can reward your plant with various benefits. Plus, it’s a great project if you want to be more involved in growing your plant!

How to Make Soil to Grow Cannabis at Home?

cannabis seedling in soil

Making your own soil can be fun and it can help you understand your soil better, which ultimately helps you grow better plants. So, if you want to make your own soil, you can do so in the following ways:

Loam Soil

Loam soil consists of sand, silt, and clay in a 40:40:20 ratio, respectively. And it is one of the best soils for cannabis because of its terrific water retention abilities and fertility levels. However, purchasing loam soil can be very expensive. So, you can just make it at home instead!

Follow these steps to make homemade loam soil:

Step 1: Test Your Soil

Since you need to maintain a ratio of 40:40:20 between sand, silt, and clay, you need to first get your regular soil tested to check how much sand, silt, and clay is already present within the soil. Depending on your location, the ratios can vary significantly.

Step 2: Purchase and Mix the Correct Soils

Once you have the tested ratios, you now need to bring the ratios to 40:40:20. For this, you need to procure the soil type that is missing. For instance, if your soil contains a lot of silt, you need to rebalance it by adding more sand and clay.

Mixing the three may take some trial and error, so be patient. 

Step 3: Add Organic Matter

Once the mix is ready, you need to add several inches of organic matter on top. After adding it, you need to stir the upper inches of the mix properly to mix everything evenly.

Once the soil has a dark, loose texture, your loam soil is ready. As a safety measure, you should pour some water into it to check drainage — the water should not pool for more than a few seconds before draining out. And you should also check the soil’s rub-off water pH to ensure it is between 6.0 to 7.0.

How to Make Super Soil at Home

super soil

If you want to take your growing medium to the next level, you can also make your own super soil. It is made by adding several slow-release nutrients followed by composting. Composting makes the soil alive with microorganisms, which are super beneficial for the plant’s roots. 

Plus, with super soil, you don’t have to worry much about supplementing the right nutrients or constantly rebalancing pH. Let nature take care of it for you.

Many growers have also reported that super soil can improve the flavor profile of the buds, which is always a welcome benefit for cannabis lovers!

Super soil also has a few drawbacks, such as:

  • Preparing super soil takes a lot of time (and sometimes money)
  • It may slow down the plant’s growth since plants need time to absorb the nutrients 

Follow these steps to make homemade super soil:

Step 1: Prepare the Base

Get yourself some high-quality potting mix, which will work as a base for super soil. You can start with 8 x 30 pounds of potting mix.

Step 2: Mix the Additives

What makes super soil, super, are the additives. So, you now have to add them to the base. Here are some of the additives you can consider:

  • Azomite (half a cup)

Coming from volcanic rock, this thing contains 70+ minerals and trace elements, including copper, silver, and calcium.

  • Bat guano (5 pounds)

Bat guano is essentially bat poop, and is a rich source of nitrogen, potassium, and phosphorus — the three essential nutrients for cannabis — and it won’t give your buds a metallic aftertaste.

  • Worm castings (25 to 50 pounds)

Worm castings, again, are just worm poop, but according to scientists, it is rich in both macro and micronutrients, which improve the soil’s fertility.

  • Blood and bone meal (5 pounds)

If you are not growing vegan plants, you can choose bone or blood meals, too. Bone meal is powdered animal bones, rich in phosphorus, which is essential for flowering cannabis.

And blood meal is made from dried cow or pig blood, and it is rich in nitrogen, which is crucial for the vegetative stage.

  • Dolomite (one cup)

Dolomite, or sweet lime, is a rich source of magnesium and calcium, and also improves nutrient retention within the soil and maintains the pH balance.

  • Epsom salt (¾ cup only)

Epsom salt improves the root’s nutrient absorption since it contains a lot of magnesium. Do not exceed the recommended amount as it can also cause a nutrient lockout within the roots.

  • Rock phosphate (3 pounds)

Rock phosphate is a natural fertilizer rich in phosphorus, which is beneficial for a blooming cannabis plant. Plus, it helps repel invasive pests. 

  • Kelp (¼ cup for every 5 gallons of soil)

Lastly, you can add kelp, which feeds the beneficial fungi within the soil that help maintain the soil’s pH balance. 

Step 3: Mix Them All Up

Once you have added the additives to the base, it’s time to mix them up. Typically, you'd have to mix everything up with a shovel for at least a week until the mix turns into one color. Then, you can store it to encourage composting. 

Your super soil should be ready to use in a month or two.

Making Regular Soil Better

coconut husk fiber

If you don’t want any special soil, you can just make regular soil better with a few simple tricks. It is easy to do and can make a dramatic difference in your plant’s growth. Here are some of the amendments you can mix with regular soil:

  • Coco coir (up to 30% of the total soil volume)

Coco coir is just ground up coconut husks, which can improve the soil’s water retention, decreasing the chance of overwatering.

  • Perlite (up to 40% of the total soil volume)

Perlite is tiny, airy rocks that improve the soil’s drainage and aeration abilities. You can also use perlite if you plan to supplement nutrients to avoid nutrient burn.

  • Worm casting (up to 30% of the total soil volume)

As discussed earlier, worm casting can improve your soil’s texture, drainage, and moisture retention. 

  • Vermiculite (up to 50% of the total soil volume when mixed in soil with perlite)

You can add vermiculite to lighten heavy soil. Plus, it improves water retention. To also improve aeration and drainage, we recommend using vermiculite with perlite.

Summary: Guide To Using The Best Soil to Grow Cannabis

Soil is a terrific gateway into the world of cannabis cultivation — something that new growers can use to grow juicy buds without having to worry about the nutrient solution and complex setups.

At the same time, for experienced growers, the soil is a tried-and-tested growing medium that can no doubt support cannabis requirements. 

So, if you want to grow cannabis in soil, ensure you use the best soil for optimal results. Follow the steps mentioned above, like recognizing the best soil, buying or making high-quality soil, and adding the right amendments, and you won’t have to worry about your plant’s health.