Robust soil is a salient prerequisite to growing cannabis. However, it is not a necessity, as cultivators may also choose to grow plants hydroponically. But such alternatives can be difficult to start and maintain for novice growers. Soil-based methods are not only simple, but also less risky, increasing the chances of an abundant harvest.
With this in mind, the type of soil you use can make or break your operations. Below provides a general overview of the kind of foundation you need to grow healthy cannabis plants.
Characteristics of Good Soil
There are numerous types of soil out there that can help cannabis plants thrive. Although the ingredients differ, generally speaking, they all have the same set of characteristics that make them viable. At the very basic level, the soil must be sterile. Parasites from unsterile soil can quickly ruin your crops and your efforts in keeping the plants alive. Because of this, using soil from your backyard or from an unknown source is not recommended. It is possible to sterilize soil with steam or in an oven, by exposing batches to high heat over a set period of time. If you’re not comfortable with sterilizing potentially hazardous soil, a great (and highly recommended) alternative is buying from a plant shop that caters to cannabis.
Other important characteristics include texture (avoid pale and crumbly soil) and water retention. Water and oxygen are primary drivers for plant growth. Addressing the latter component, cannabis soil should be able to retain enough water to ensure the plants don’t dry out. On the other hand, too much water will make it harder for the roots to gather oxygen, resulting in droopy-like growth.
Ideally, you want the soil to be light and loose to prevent weighing down the plants. It is vital to consider that for indoor operations, most nutrients come from the grower – so the root system does not need to be extensive. Cannabis plants that are grown outdoors rely on long roots to find water and nutrients. Furthermore, the temperature of the soil should be fairly warm, at roughly 68°F with the right pH values (between 6.5 and 7.5, as acidic soil is not suitable for cannabis – unless you want mostly male plants).
These days, one can find a wide selection of soil mixtures. The mixtures are typically designed, sterilized and optimized specially for cannabis. If you’re taking this route, be sure to carefully read the label, as some pre-mixed soils for house plants contain components that are actually harmful to cannabis. Common ingredients found in good cannabis soil are kelp, fish meal, casings, sandy foam and more.
If pre-mixed soil for cannabis is unavailable in your area, it would also be possible to create your own mix. When going with this option, one should start with clean soil (no nutrients). Lastly, don’t forget that some ingredients, like rotting vegetables and manure, must be broken down before they can be introduced and absorbed by the plants. Water and insects are effective in streamlining this process.
This post was originally published on July 5, 2017, it was updated on October 5, 2017.