Irrigation management is a critical aspect of cannabis cultivation. Water is a key driver of photosynthesis and influences productivity, cannabinoid levels, and terpene content. Therefore, insight into water consumption is important for any cultivator.
Tom de Vreugd, Grower Success Manager at Growficient, says: "Our wireless substrate sensors and online platform provide accurate insight into the water content, EC, and substrate/environment temperatures of all types of substrate. They will allow you to identify your heavy drinkers versus slow drinkers, and optimize your irrigation schedules. Ultimately leading to more efficiency in managing plants, better placement of cultivars, and consistent high-yielding batches".
Genetic influence
So why is insight into water consumption so relevant for a cannabis cultivator? "Let's start with the basics. The watering needs of cannabis plants can vary widely, depending on two things", says Tom. "One, the specific cultivar, and two, the environment it grows in". Tom explains that every single cannabis cultivar has a genetic preference when it comes to water consumption. "Even before a plant grows out to maturity, its genetic blueprint influences transpiration and the amount of water needed to grow, just like humans. Some people sweat more than others. With plants, it is quite the same."
Environmental influence
Next to genetic influence, Tom remarks that "the environment around the leaves determines water consumption (based on temperature, humidity and airflow). Cannabis plants use the process of transpiration to cool down. So when a flower room is running hot, plants will generally need more water." Tom notes that the watering needs of a cultivar are always in motion. "It is a delicate interaction between genetics and all cultivation parameters that the plant is exposed to. All the more reason to monitor water uptake with the use of sensors", according to Tom.
Groups and clusters
He continues to explain that different cannabis varieties have distinct water consumption patterns. "Cultivars can be categorized based on their water consumption needs. Some are "heavy drinkers," meaning they require frequent watering and a higher amount per day. Other cultivars, on the other hand, are dubbed "slow drinkers". They need less frequent irrigation and a lower volume of water per day."
Heavy drinkers typically exhibit a faster growth rate and higher transpiration. They lose water more quickly and need to be watered more often. If their watering needs are not met, these plants may show signs of wilting or nutrient deficiencies. On the other hand, slow drinkers might thrive with less water and overwatering can lead to root diseases and other issues.
Why is this insight crucial?
According to Tom, there are two reasons. "Firstly, misjudging a plant's water needs has significant consequences, such as stunted growth, poor nutrient uptake, and crop loss. While visual cues and experience can provide some guidance, they often fall short of delivering the precision needed for optimal irrigation." "Identifying and optimizing irrigation using wireless substrate sensors leads to higher yields, more consistency, higher quality, and most importantly: fewer problems".
"Secondly, categorizing cultivars is a game changer. It allows genetics to be grouped in the same irrigation zone. For example, all heavy drinkers can be placed in one zone of the flower room and all slow drinkers in another. This means that irrigation schedules can be tailor-made and optimized with less compromise. There is no need to adjust irrigation based on the heavy drinkers and therefore overwater other cultivars". Tom clearly states that this method will increase the output and quality of any room.
He goes even further. "In the Growboard, our online dashboard, all these things become visible in a clear overview. It is super insightful to see irrigation trends of cultivars over time and the interaction between genetics and the environment. This provides more objective data to make better decisions".
Monitor absolute dryback per cultivar
Tom concludes: "Finally, dryback is another crucial variable to differentiate the water uptake. It refers to the process of allowing the substrate to dry out between watering events." The amount of dryback encourages expanding roots and influences vegetative or generative steering. More dryback means more generative growth. The plant will focus on flowering. Less dryback means more vegetative growth and stimulates leaves and stems.
"You can also get a quick insight into the dryback between irrigation shots and dryback overnight in our Growboard. Our dryback feature makes crop steering per flowering phase so much simpler, and is the perfect tool to identify heavy- and slow drinkers. By monitoring your drybacks closely, setting thresholds and using them to crop steer effectively, you can generate more yield and quality. "This is where the magic happens," Tom concludes.
For more information:
Growficient
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growficient.com/cannabis