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Growing your own cannabis can be fun and easy, but finding the best soil for growing weed can be the difference between a stressed-out marijuana plant and a cannabis plant rich in diamond-like trichomes.

The type of soil, also called a grow medium, needed for cannabis plants depends on many factors including the grower’s preference. Beginners should have fun experimenting with different potting soils to find the best one for them.

What Is Soil And Why Is It Important?

Soil is a necessary component of a plant’s growth cycle. In nature, the soil is the upper layer of earth where plants grow. Soil usually consists of organic materials such as clay and rock. Cannabis growers can use pre-made soils or build their own mixture. When it comes to finding the best soil for weed, growers should consider the soil mixture’s texture and ability to influence pH level, water retention, drainage, and nutrient intake.

Soil can have varying textures ranging from sandy to silt to clay textures. Each type of soil has its unique advantages and disadvantages on its ability to retain water, provide roots with oxygen, and provide stability to the plant. Soils can also impact the pH and nutrient intake of a cannabis plant’s roots.

 So, why is it so important to find the best grow medium for your cannabis plant? Different elements of a soil mixture contribute to healthy cannabis growth. Clay helps the soil retain moisture, while the rocks and sand provide drainage. The best marijuana growing soil for weed contains a mixture of textures that are easy to work with and provide the plant’s roots with the water, oxygen, and nutrients they need. A grow medium serves three main functions:

  • To physically support the plant.
  • To supply roots with nutrients, air, and water.
  • To allow for maximum root growth. Roots grow where the media isn’t.

Consider Drainage And Aeration

Besides regularly watering a plant and providing the roots with the right nutrient levels, growers must control the soil’s ability to drain the water. Without proper drainage and aeration, plants can quickly drown, burn from salt buildup, or rot from the excess water. Growers should ensure the container and soil medium are porous enough to drain and have pockets of air for oxygenation.

 When finding the best soil for growing marijuana, cannabis growers can optimize the soil with different materials such as perlite or vermiculite to improve drainage and aeration. When water begins to puddle on the surface of the soil, the soil needs to be improved.


Perlite is a volcanic mineral that can grow up to 20 times its original volume when heated at high temperatures (1600º to 1700ºF). Crude perlite contains water that pops like popcorn when heated. Perlite won’t absorb any liquid but will create tiny spaces within the soil to improve aeration and drainage for the marijuana plant’s roots.


Vermiculite, also known as puffed mica, is made form muscovite mica, a sheet silicate. Unlike perlite, vermiculite is effective at absorbing liquids and improving air and water retention. Users should wear a respirator or face mask when handling vermiculite and wet the vermiculite to avoid inhaling any dust.

Pre-Made Soil

Pre-mixed soil from a gardening store can be a great start for first-time cannabis growers. Cannabis growers should look for natural and fresh potting soil instead of other soils listed with labels such as “extended release,” “controlled release,” and “lightweight formula.” Growers should also consider adding perlite into the mix if the soil does not contain it for better drainage.

Living Soil

Living soil contains a diverse mixture of bacteria, fungi, protozoa, nematodes, arthropods, and earthworms that help break down organic matter for healthier soil. In the wild, a complex and biodiverse ecosystem works together throughout the growth cycle. Over time, living soil can become richer and more stable. Growers can add more living soil as needed to restore depleted components.

Hydroponic And Aeroponic Systems

Soil-less media used in hydroponic and aeroponic systems are becoming more popular in the cannabis community. While soil-less media provides the plant with structural support, it does not provide the plant with nutrients and water. Soil-less media is made of substrates and is sterile due to its lack of living organisms.


Rockwool is an inorganic medium made from basalt and chalk. The rocks are melted and blown into a large spinning chamber to create a fiber-like texture. Rockwool’s porous nature allows the roots to get air and water. Rockwool comes in cubes and mats in multiple sizes.


Hydroton comes in pebble form and is made from an orange-red clay, similar to terra cotta pots. This clay pebble is great at retaining water to keep a plant’s roots from drying out, The pore space between hydroton pellets can improve aeration and prevent root rot. Hydroton also helps roots absorb nutrients, lower pH, and can be re-used for multiple crops.


Coco, also called coco noir, is made from the fibrous strands between the husk and the meat of a coconut. Just add water and the strands expand leaving enough pores to keep the roots well aerated. Coco contains a trace amount of nutrients such as phosphorus and potassium making it a popular grow media for cannabis.


CocoNot is an eco-friendly medium made from a sustainably harvested layer of Redwood bark mixed with Kapok fiber. It also contains 20 percent lignin, useful for protecting the plant against pests and pathogens. CocoNot does not hold moisture very well, which means growers must regularly water the marijuana plant.

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