How to Choose the Right Amount of Soil and Container Size for Cannabis Cultivation

Different cannabis cultivators have their own preferences for the amount of soil and container sizes they use. This decision could even be based on state regulations. However, it’s a decision that should be evaluated comprehensively for every facility.

In order to do your own evaluation and make the best decisions, you need to fully understand two key factors that determine the right amount of soil and the right container size for optimal results. Let’s take a closer look at these two critical factors.

1. Canopy Size and Root Volume

The first consideration when choosing the amount of soil and container size for cannabis cultivation is the desired canopy size. A cultivator who wants to grow a larger canopy will need larger containers and more soil. However, that’s not a strict rule because a lot more goes into the amount of soil needed to grow a specific canopy size than just a certain number of gallons.

The factor that makes all the difference in the amount of soil needed is the void space available in the soil. Void space refers to the non-solid space, which is space that is available for air, water, and roots.

A desired canopy size is tied directly to root volume, so the soil you use must provide enough space to maximize root volume. If there isn’t room for roots to explore and grow, plants will only reach a certain size. Said another way – your plants need bigger roots for you to grow a bigger canopy, which means there must be space available in your soil and containers for those larger roots to fit.

Here’s an example to put this science into perspective. Grow media from bio365 is typically 80%+ void space, which can be filled with water, air, and roots. If a soil has a higher percent of solids, there is less space available to the plant’s roots. Competitor soils have a lower per unit volume of space for roots than bio365 media. Therefore, plants’ roots can grow larger – and so will your canopy – when you use bio365 media, and you’ll need less bio365 media to get the same or better results.  

2. Feeding and Watering

Once you’ve chosen the soil you’ll use and understand the soil’s void space and formulation, you can fine tune your watering and feeding schedule to maximize your outcomes. You can either tune to fit with your desired feeding and water schedule or modify your schedule depending.

However, you can’t optimize at all if you don’t understand the air-filled and water-filled space in your grow media, which can vary between companies as well as between one product and another from the same company.

As an example, consider bio365’s BIOCOCO vs. BIOLITE media – BIOCOCO holds more water per unit volume than BIOLITE. Therefore, if you have one gallon of each media, the gallon of BIOCOCO will hold more water than the gallon of BIOLITE. The difference in water-holding capacity has a significant effect on a grower’s watering schedule.

Key Takeaways about Choosing the Right Amount of Soil and Container Size

The most important thing to remember is that you should first confirm the void space in the soil. Once you’ve made your soil decision, fine tune your watering and feeding schedules based on that soil’s composition to get the best results.