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Cannabis Soil: A Guide for Home Growers

It’s a good time to be a cannabis lover.  The number of cannabis products available today is bountiful and ever-growing.  There’s something to suit even the most selective of connoisseurs.  While shopping around and sampling new cannabis products may give you that “kid in the candy store” feeling, there’s nothing quite like planting, nurturing and growing your own cannabis plants at home.  Your tender care, directly reflected in your plant’s growth, and that exciting and proud day your plant is ready for harvest just can’t be topped.   If you’re going to grow cannabis though, one thing you’ll definitely need is the right soil.  There’s a lot that goes into growing a healthy and happy cannabis plant, but by using the right soil, your canna-baby will be off to a great start.

Cannabis Soil is Just Soil Right?

While cannabis soil is indeed soil, what the soil is made up of can drastically change its characteristics and impact the growth of your cannabis plant.  When deciding on the best soil for your cannabis plant you need to consider the following attributes:

  • Texture
  • PH level
  • Nutrient makeup
  • Water retention
  • Drainage

Texture for Cannabis Soil

The texture of the soil refers to the granular form and is an important attribute to be aware of when growing cannabis.

  • Sandy soil will have a large granular size allowing for excellent drainage and higher oxygen levels. However, since the soil is fairly loose, it doesn’t retain any of the water or nutrients your cannabis plant needs to grow.
  • Silty soil has lots of nutrients and can retain water but is too easily compacted leaving no room for your cannabis plant’s roots to grow.
  • Clay soil provides great minerals and also retains water very well, however, similar to silty soil it can become too compact which makes it poor for drainage

Now if only there was a soil that combines all of the attributes of the different textured soils listed above.  Well, good news!  There is and it’s called Loam Soil.

  • Loam soil is made up of less than 52% sand, 28-50% silt and 7-27% clay. Its porous texture creates the perfect combination of water retention and drainage allowing your cannabis plant to absorb the water it needs without getting waterlogged.  Unfortunately, this ideal blend of soil comes at a cost.  You can find it at most garden stores as potting soil.

PH Level for Cannabis Soil

The PH level of the soil is a chemical measurement of how alkaline or acidic it is.  Cannabis requires a very specific PH level of 6.0 to thrive.  A slight variation in PH should still be fine but if your PH is too high or too low your plant will die.  If you’re wondering how to do a soil PH test check out this link.

Nutrient Makeup for Cannabis Soil

Cannabis soil will require a good dose of nutrients to get your plant off to a great start.  Most of the bags of soil you can buy at a garden store already have a good supply of nutrients which will usually last for the first month of growth.  After that, it will be up to you to supply your plant with the nutrients it needs.  Adding in some good quality compost, worm castings or guano will allow the microorganisms in the soil to break them down and create an excellent source of nutrients for your cannabis plants.  There are also nutrient solutions which you can purchase at your local garden store to help fine-tune your cannabis soil.

Homemade Cannabis Soil

If you’re new to growing cannabis, store-bought soil can be an excellent way to start.  It will supply you with a well-balanced, nutrient filled solution to get you started with very little effort.  However, if you’re ready to take your cannabis growing to the next level, why not start by creating your own special soil blend!

Cannabis Soil Base

To get started, you’ll need to begin with a good base.  Three components you’ll need for your base are compost, coco coir and perlite.  A good rule of thumb is to use 1 part compost, 1 part coco coir and 1 part perlite.


Those kitchen scraps you’ve been composting can become the first contributor to your soil base.  Good nutrient-rich organic waste makes for an excellent base starter.

Coco Coir

Made from coconut husks, coco coir is an excellent fibrous addition for your cannabis soil.  If you find your soil is too compact, adding up to 30% coco coir will help with water retention and provide aeration for your soil


If you’ve ever noticed little bright white rocks in soil, it’s most likely perlite.  The light airy properties of perlite will lighten your soil and provide better drainage.  Be careful not to add too much though as you need to maintain a nice balance of airiness and water retention.


After you have your base you’ll need to focus on diversifying the microbiological makeup of your soil.  One way to do this is by building fungi mycorrhizal relationship with the roots by adding:

  • Kelp meal: 2.5tsp / gallon
  • Humic acid: 2.5tsp / gallon
  • Mycorrhizal inoculant: 1/2tsp / gallon


In order to keep your cannabis plants healthy and resilient to weather, pests and disease you’ll need to make sure you introduce a healthy amount of bacteria.  Worm castings and bat guano are excellent for this.

  • Worm castings: 20% of your mix
  • Bat guano: 5% of your mix

Micro and Macronutrients

Your cannabis plant will thank you for adding a healthy mix of micro and macronutrients.  These can be easily added by mixing in some good quality plant fertilizer.

Most importantly, remember to have fun!  Experiment, practise and play.  Creating the perfect cannabis soil is a trial and error process which will require constant tweaking and fine-tuning to cater to your plant’s needs but seeing your cannabis grow into a strong and healthy plant is very rewarding and well worth the effort.  So get outside, get your hands dirty and give it a try!  When you’re puffing away on the fruits of your own labour, it’ll taste that much sweeter.