There are a multitude of factors to consider when starting a cannabis cultivation project. From lighting, to nutrients, to cultivars and spacing, the variables are seemingly endless and this article will focus on one of the most important factors, grow medium. The medium that you decide to cultivate your plants in is paramount to the plants, and your own, happiness! There is no right or wrong answer either, it all comes down to what type of system you want to run.
Coco Coir
Coco is a great option for growers of all types. It is an excellent option for beginners and intermediate growers due to its more forgiving nature, especially when it comes to over watering! It is naturally light and airy which allows your roots to grow rapidly and have access to plenty of oxygen. Coco is a completely inert medium, which can be a pro and a con depending on the grow and grower. One of the benefits of coco is it allows you to control exactly what your plants are being fed, how much, and how often. On the flip side, this means that you need to have your nutrient regiment and pH dialed. There are no buffers like in a normal potting soil so keeping your pH in the preferred range for coco is critical to your plant’s success. If you have the right feeding regiment and pH is in range, you can feed the plants more often and more heavily which will result in more rapid growth. Along with better control of your inputs, coco is also much easier to flush at the end of a feeding round when compared to normal soil. In addition to that, coco has a much lower risk of containing pathogens and pests in the medium.
If you decide to utilize coco, it is important to understand its cation exchange capacity. The cation exchange capacity of coco is much different than soil or any other growing medium. The most common deficiencies when cultivating in coco is calcium and magnesium. To avoid these deficiencies, you will need to satisfy the coco’s cation exchange sites with cal/mag otherwise the coco will absorb the cal/mag you are trying to give to the plant. I highly recommend pre-treating or buffering your coco with a generous amount of calcium and magnesium prior to putting your precious plants in the medium. Once you have buffered the coco’s cation exchange sites, they will remain stable and future feedings will be made bioavailable for your plants! Another potential challenge to growing in coco is it needs to be flushed prior to use to get all preexisting salts out and stabilize the pH. Many Coco Coir manufacturers address this issue by triple washing their coco so by making smart vendor selections, you can ensure more reliable results from your coco.
Traditional Potting Soil
If you decide to use traditional potting soil, there are many more factors to consider. The primary factors to take into consideration are the soils ability to drain, texture, nutrient makeup, beneficial microbes present, and water retention. One large benefit of growing in traditional soil is it already has nutrients and beneficial microbes present. A lot of the mainstay potting soils found in your local grow stores come with enough nutrients to subside your plant for several weeks. This is obviously beneficial because it saves money and time having to buy and structure nutrients for some of the run. Once the nutrients have been depleted you can top feed dry nutrients or add nutrients to your waterings, much like if you were growing in coco. There are however some downsides to this. Some soils will come “hot”, meaning too many nutrients causing your plants to show signs of nutrient burn upon transplanting. Another factor to consider when structuring your soil with additional nutrients is whether or not you are adding the right amount! If you don’t use enough you will start seeing deficiencies. If you use too much you will find it difficult to properly flush all nutrients out of the soil prior to harvest. Soil also has much better water retention than Coco which can be a pro and a con. It allows you feed/water your plants less frequently, but it also makes it much easier to overwater your plants.
When deciding what medium to grow your plants in, it really comes down to your individual goals and time availability. I would say if you’re looking to spend less time in your garden properly structure your soil and let it ride! If you are looking to maximize your plants growth and output while putting more time in the garden, rock Coco Coir!
Sam Gesten
Head of Cultivation, Highland Provisions