Buenas prácticas para controlar el pH del cannabis
Editor’s note: Balancing pH is a critical component to ensuring nutrient solubility and uptake for cannabis. As part of the upcoming release of the Fluence Cannabis Cultivation guide (available later this month), we are releasing tips on how to measure and monitor pH to ensure your fertigation strategy is not a limiting factor to your use of high-intensity LED lighting.
The pH scale — which ranges from zero to 14.0 — provides insight into how chemical compounds will interact with one another based on their ionic state. It is good to remember, pH reflects the concentration of hydrogen ions in a solution. More intuitively however, pH from a practical sense can be understood in terms of acids (vinegar, ammoniacal nitrogen) and alkaline bases (baking soda, potassium bicarbonate).
Leyenda: La disponibilidad de nutrientes aumenta o disminuye en función del pH. Un nivel de pH de 5,8 - 6,2 es adecuado para el cannabis.
On the pH scale, values less than 7.0 indicate acidity; values greater than 7.0 indicate alkalinity. Deionized water has a neutral pH of 7.0. The pH scale is a logarithmic function, so even small changes in pH values are significant. For example, a pH level of 4.0 is ten times as acidic as a pH level of 5.0. For plants, pH is important because it affects the form of the nutrients in the substrate.
For example, when pH is low, the solubility of some micronutrients like iron and manganese increases, making them more available to plants. This can cause toxicity. However, when pH increases, micronutrients, along with phosphorus, become less soluble and less available to plants.
Regardless of the concentrations of your nutrient solution, unbalanced pH levels can create an antagonistic environment for nutrients and will make them unavailable to your plants. The figure above shows how nutrient availability relates to pH.
Cannabis, like many plants, prefers slightly acidic soil conditions. It tolerates a wide pH range (5.0-7.0) without symptoms of bronzing or interveinal chlorosis (yellowing of top leaves), but pH levels outside of the optimal range of 5.8 – 6.2 will limit growth. To maintain optimal pH levels, cultivators should test pH levels every two days, and adjust the pH as needed.
Comprobación del pH con un medidor digital
Comprobar el pH es fácil. Los medidores combinados de pH/CE son relativamente baratos y su uso requiere poca formación. Ofrecen una solución permanente a las tiras reactivas de pH desechables y a los kits de tintes, que son engorrosos y deben interpretarse subjetivamente por el color del material reactivo de la prueba.
- Calibre el medidor: Antes de realizar un análisis, los medidores deben calibrarse con un patrón conocido. En este caso, calibrar contra agua purificada tiene un valor de pH neutro de 7,0. Asegúrese de que el agua que utiliza está desionizada. Sumerja la sonda del medidor en el agua y ajuste la pantalla para que indique pH 7,0.
- Pruebe la solución: Sumerja la sonda en un recipiente con la solución fertilizante o directamente en el depósito. Lea la pantalla digital.
- Pruebe el medio de cultivo: El entorno electroquímico de la zona radicular puede ser diferente al de la solución fertilizante. La acumulación de sal puede provocar concentraciones de nutrientes en las raíces, lo que hace que los niveles de pH sean diferentes a los del fertilizante. Para comprobar el pH en las raíces, permanezca atento al blog de Fluence, ya que en las próximas semanas publicaremos una guía de buenas prácticas para comprobar la conductividad eléctrica (CE).
We hope these tips have been a helpful reminder of how to leverage pH tests in your grow.
