Cannabis relies almost entirely on its root system to deliver the water and nutrients required to power growth and the medium you choose to grow in will have an impact on how fast your plants grow. In this chapter, we’ll provide an overview of the different options and then provide a recipe you can use to make your own soil based growing medium.
What makes a good medium?
Growing mediums that work well for cannabis will have the following traits:
- Provides water without generating root-rot
- Provides access to air - roots need air to power cellular processes
- Maintains pH balance to efficiently deliver nutrients.
What growing mediums are there?
Basic soil, or dirt, is the oldest and most common medium for growing cannabis. Common garden soil isn’t great for cannabis and basic potting soil leaves a lot to be desired. If you are looking to produce top quality cannabis, you will need to supplement soil to increase its airyness, improve its pH balance and buffering and to improve nutrient delivery.
Pros - Inexpensive, commonly available, easy to work with and familiar to most farmers.
Cons - Soil doesn't deliver nutrients as efficiently as hydroponics or organic mediums and it requires supplements to reach its top performance.
Hydroponics is all about using water to carry dissolved nutrients and air to your roots without the use of soil or other medium. Hydroponics typically works by growing roots directly in water with dissolved nutrients that is being circulated and aerated. Hydroponics is an advanced growing topic and is covered in later chapters.
Pros - Faster growth and reduced water usage.
Cons - Much more expensive, complicated and error prone than other mediums.
Inert Organic Medium
Inert medium is a type of soil-like medium that, unlike soil, does not have any nutrients itself for plant consumption. Growing in an inert medium is a form of hydroculture, like hydroponic, in that you are growing plants without soil, by instead using mineral nutrient solutions in a water solvent. Common inert ingredients include coconut husk fibers (Coco Coir), peat moss, perlite and vermiculite.
Pros - Fairly cheap and available with better potential results than soil.
Cons - Less pH buffering than soil.
What kind of medium should I use?
For new growers, we recommend that you start with a soil mixture that is formulated specifically for Cannabis. There are several mixes available on the commercial market, which are most often a mixture of soil and inert medium. In the next section, we’ll show you how to make your own from commonly available ingredients and after that we’ll cover some commercial options.
You may also choose to grow in a 100% inert medium to take advantage of hydroculture’s nutrient delivery ability. Take caution because inert mediums do not have great buffering properties, which means that incorrectly dosed nutrients and unbalanced pH is passed directly to the roots and the plant is impacted immediately. Soil provides better buffe
Can I make my own soil mixture?
It is relatively easy and cost effective to make your own mixture from commonly available ingredients. The most important part of any soil based medium is that it:
- Drains excess water well, but doesn’t dry out too quickly.
- Light and airy enough - compacted soil will stunt root growth.
- Maintains pH balance, and efficiently delivers nutrients.
Read this guide to learn how to make your own high-quality soil mixture.
Can I buy a quality soil mixture?
If you're looking for a premix that's optimized specifically for cannabis, several options have been designed by experts specifically for marijuana. We have tested several and found them to be extremely useful mediums.
Roots Organic Potting Soil Mix - Specially formulated for weed, Roots Organic Potting Soil is a loose mixture of soil, coco and perlite.
Fox Farm's Coco Loco Mix - Part of their organic BushDoctor line, this mix is heavy in coco for high water retention.