Problem: With a cannabis zinc deficiency, younger leaves start yellowing in between the veins. Leaf tips get discolored and start dying. the leaves may take on a unique banded appearance and the plant may stop growing vertically. There may be much less space between new nodes, which can cause new leaves to start bunching together. If the plant is budding, its flowers may stop growing or even start dying if the problem isn’t corrected.
Solution For Cannabis Zinc Deficiency
Note: Sometimes a cannabis zinc deficiency (like all deficiencies) can be triggered by stressful conditions and may clear up on its own after the period of stress is over. However, to minimize damage it’s important to react to any growing problem as quickly as possible, especially in the flowering stage.
1.) Adjust pH to Correct Range
The most common reason growers will see a zinc deficiency is when the pH at the roots is too high. Zinc tends to get locked at higher pH levels and is better absorbed by the plant in a more acidic root environment.
If you suspect your growing cannabis plant has a zinc deficiency due to too-high pH, flush your system with clean, pH’d water. This will remove any nutrient salts that may be affecting the uptake of zinc and help restore pH to the proper levels.
- In soil, zinc is best absorbed by the roots in the 6.0 – 6.5 pH range (although it’s generally recommended for soil growers to keep pH in the 6.0-7.0 range, zinc tends to be absorbed better on the lower side)
- In hydro, zinc is best absorbed by the roots in the 5.5 – 6.0 pH range (although it’s generally recommended for hydro growers to keep pH in the 5.5-6.5 range, zinc tends to be absorbed better on the lower side)
Learn how to manage your pH for growing cannabis.
2.) Give the Right Nutrients
The truth is, most cannabis growers don’t need to add more zinc in response to a zinc deficiency!
In fact, most growers have actually already given plenty of zinc to their cannabis plants since it is found abundantly in most tap water. If you’re using quality soil or cannabis-friendly nutrients, you probably don’t need to worry about adding more zinc. In general, zinc deficiencies are more likely to appear when a grower is using heavily filtered or reverse osmosis (RO) water to feed plants since any zinc has been removed, but pH is a much more common reason growers see zinc deficiencies in their cannabis plants.
3.) Take Good Care of the Roots
Zinc deficiencies can show up with the plant is having root problems or if the plant is overwatered, even if the pH is right and the zinc is there. Proper watering practices help plants grow healthy and avoid a host of problems!
4.) Watch for Recovery
After going through all the above steps, watch to make sure that the zinc deficiency starts to clear up within a few days to a week or so. The damaged leaves may not recover completely, but you know you’re in the clear when you stop seeing symptoms on new leaves.
If you cannot get rid of a cannabis zinc deficiency, please consult our 7-Step Cure to 99% of Cannabis Growing Problems