Cannabis and pH
Growing cannabis is not simple as it seems. One of the biggest challenges growers face is nutrient deficiencies, even with balanced feeding. This is because the roots may not be absorbing every nutrient. The pH levels need to be within certain ranges for roots to adequately absorb nutrients.
The pH of your growing medium should always be the first thing to check before identifying cannabis deficiency. For soil or similar grow mediums, a pH range of 5.8 to 6.8 is required, with 6.3 being the target. Many soils and grow mediums will naturally balance out to the correct pH level. However, hydroponic growers commonly average around 6 if following manufacturer nutrient recommendations.
Know the pH of local water as it varies and may not always be the same throughout the year. Water treatments and rainfall can affect pH levels at the tap. Monitoring the water pH levels can help avoid improper pH in the growing medium.
Additionally, there may be higher amounts of minerals within local water ranges between regions. If the water supply has varying minerals, it can become a challenge to maintain proper minerals for the plants. Many professional growers eliminate this variable by using deionized water for their plants.
Deionized water has all the minerals filtered out, leaving pure water. If used from the start of your growing, it can make maintaining specific nutrient balances. For the average cannabis home grower, tap water is often used and gets the job done.
Cannabis Deficiencies, Micronutrients, and Macronutrients
Cannabis plants need trace amounts of the following nutrients for cellular growth and function: Sulpher, Zinc, Silicon, Copper, etc.
Cannabis plants need larger amounts of these nutrients for the biochemical processes during both growth and bloom. They include Phosphorus, Potassium, and Nitrogen.
Cannabis Deficiencies: Immobile vs. Mobile Nutrients
It can be important to know the differences between mobile and immobile nutrients, as it helps identify deficiencies. Mobile nutrients, like Phosphorus, are transferred between different parts of the plant. That means to identify a phosphorus deficiency, you would look at older growth compared to new growth.
Immobile nutrients include minerals like Zinc, which remain mainly in the part it is applied to. Immobile nutrient deficiencies will appear first in new growth.
Prevention vs. Cure
Cannabis cultivation, as with most crops, prevention methods work better than cures and treatments. Many growers misinterpreted mineral deficiencies and applied incorrect treatments, which makes it worse. There are cannabis deficiencies with similar appearance and are hard to identify by sight alone without experience.
Soil growers can reduce nutrient deficiencies by using larger containers for growing with professional, high-quality soil. If formulated correctly, more soil allows cannabis roots to grow larger and absorb more nutrients.
Sometimes plants will have multiple nutrient deficiencies, especially in lower quality mediums. However, if the pH of the soil is not within range, it can be causing “nutrient lockout,” meaning the nutrients are there but not being absorbed.
How To Identify and Treat Nutrient Deficiency in Cannabis
If your plants are lacking certain nutrients, being able to identify them and treat them fast is important. Ignoring nutrient deficiency can have a major impact on harvest and could even kill the plants. Healthy plants can resist diseases and pests better than those with poor nutrition and health.