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zinc deficiency in cannabis

Zinc Deficiency

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)

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

Plant Symptoms

  • Bronze or brown patches
  • Brown or slimy roots
  • Brown or yellow leaf tips/edges
  • Buds dying
  • Buds look odd
  • Bugs are visible
  • Curling or clawing leaves
  • Dark leaves
  • Drooping plant
  • Holes in leaves
  • Mold or powder
  • Pink or purple on leaves
  • Red stems
  • Shiny or smooth leaves
  • Spots or markings
  • Twisted growth
  • Webbing
  • Wilting leaves
  • Yellow between leaf veins
  • Yellow leaves

This page is part of our Plant Doctor series. You can use our tool to filter by symptom and help diagnose your plant.

Problem: A cannabis zinc deficiency causes younger leaves to start yellowing in between the veins. Leaf tips get discolored and may start dying.

Zinc deficiency in cannabis

Zinc (Zn) is a micro nutrient as well as an immobile element. Your plant doesn’t need much of this nutrient but it does play an important role in your plants size and maturity. The procuction of leaves, stalks, and branches is also needing Zinc(Zn) as well. It also plays an important role in many enzymes in addition to the growth hormone Auxin. It also is there for working with the chlorophyll and helps your plant handle long droughts helping your plants absorb moisture.

Deficiencies can be seen by the bleach spots between the veins which appear in the beginning on the older leaves and then goes on to the immmature leaves. Zinc(Zn) not being a mobile element will show its deficiency on the newer growth.

The PH levels of your plants to keep this element from being locked out is in soil at more than 4.7 and less than 9.5. In hydro and soiless it is 4.25 or less and 8.5 and above to keep this element locked out.

This can be treated by adding organic fertilizer containing Zinc(Zn) or by burying galvanized nails in the soil.

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In San Luis Obispo at the Healthy Harvest store they recommend getting one of their fine micro-nutrient products which have small amounts of all the micros your plant could need including Sulfur(S). In particular they like the CNS17 from Botanicare. It works out real nice that as long as your plants aren’t flowering it works as an excellent foliar feed so the results will show up much quicker. You can also use this as an additive to your water which works good too.

zinc nutrients in marijuana