How to Spot and Correct a Copper Deficiency in Cannabis Plants
Let’s talk about Copper (Cu) as a nutrient that you’re probably not paying enough attention to, but is absolutely vital for the health of your cannabis plants. Copper deficiency in cannabis plants is usually due to a pH problem so it’s easy to misdiagnose it.
There are a bunch of interesting ways that a Copper deficiency can be spotted and it can even display as purple shades that a novice grower may mistake for an expression of the strain itself. So let’s take a look at how to diagnose, correct and prevent a Cu deficiency from killing your yields.
(Cu) Copper: Activates enzymes, necessary for photosynthesis and respiration.
Deficiency: Deficiencies are not very common and are usually caused by pH issues in the medium. The first signs are that the leaves get a bluish hue and change to a stiffer texture. In the later stages, a Copper deficiency leaves to necrosis and diminished yield.
Toxicity: Excessive Copper may reduce the availability of Iron.
Micronutrient: Absorbed in small to minute quantities. They are generally less well known than the macronutrients since most plant foods don’t contain them.
What Does Copper Do For Cannabis Plants?
Copper is much like the quiet kid in the class who silently holds everything together. You don’t pay much attention to Copper unless it’s missing, and then your whole life gets turned upside-down.
Copper acts as a catalyst in several key processes in the cannabis plant. It plays a crucial role in the synthesis of proteins and enzymes that make up the bulk of the plant. Copper aids in the formation of lignin which is used in the cell walls and provides the plant with their structural integrity.
It’s also involved in pigment formation, contributing to the vibrant green color we all love to see in our cannabis plants. That is why a deficiency in Copper quickly can be spotted on the color of the leaves.
How Does a Copper Deficiency Affect the Quality of Cannabis Plants?
When cannabis plants suffer from a copper deficiency, it’s as if the inner workings of a finely-tuned watch have been tampered with. In the flowering stage, this means that the quality of the crop gets vastly decreased in both yield and overall quality.
Copper is fundamental for the plant’s growth and flowering processes. When there is a lack of Copper, there are important processes don’t function properly, leading to slow growth, smaller yields, and buds that lack potency and terpenes.
A copper deficiency can also make the plants more susceptible to disease. Especially when paired with a Silica deficiency. Talk about a trifecta of trouble!
So What Are the Symptoms of a Copper Deficiency?
Identifying a plant copper deficiency can be a bit tricky because it’s an uncommon occurrence but as the deficiency progresses, you will start to see color and leaf texture changes that are unique to a lack of Copper.
The Early Stage of a Copper Deficiency
In the early stage of a Copper deficiency, you see changes in new growth as your plant’s leaves start taking on a peculiar bluish hue with purple undertones. If you are a novice grower or are growing a new strain, you may be inclined to think that the purple tones are pretty and mistake it for dankness.
The veins and petioles (leaf stems) start turning purple, and the leaf tips might twist or curl (similar to a Zinc deficiency). Newer growth may also start to exhibit a mild chlorosis or a yellowing.
The Progression of a Copper Deficiency
As the deficiency progresses and is left untreated, these symptoms become more pronounced. Yellowing will spread across the entire leaf, and spots of necrosis, or tissue death will start to appear as brown spots.
You may notice your plant’s leaves curling upwards, a phenomenon often referred to as “cupping” and that the leaves feel stiff and look shiny.
The Late Stage of a Copper Deficiency
If left untreated, the late stage of a copper deficiency gets much worse as the areas of necrosis grow larger and darker, and the leaves become crispy to the touch. They eventually start to break, crumble and fall off the plant as they die.
What Causes a Copper Deficiency and What are Common Misdiagnoses?
By far the most common reason for a Copper nutrient deficiency is a problem with the pH levels in the growing medium. If your pH is off, nutrients can lock out, making them unavailable to the plant even though they are abundant in the growing medium.
Copper deficiency is often misdiagnosed as either a nitrogen deficiency or as overwatering. The symptoms are fairly similar in the early stages but gradually you should start to see that leaves turn bluish and shiny with a harder texture if it’s a Copper issue.
How to Fix a Cannabis Copper Deficiency
Correcting a Copper deficiency is not as difficult as it may seem. The important thing is that you diagnose it as early as possible so you can start make corrections before it’s too late.
As mentioned earlier, most cases of Copper deficiency stem from a pH issue in the growing medium. So start by using a pH meter to check that the pH is between 6.0 – 6.5 for soil or 5.5 – 6.0 for hydroponics. If the pH is way off, you may need to flush the system (learn how to flush cannabis plants here) and add in a new and balanced nutrient solution with pH-balanced water.
Also, check the root zone for any signs of rotting that may be causing the problem.
You should start seeing improvements in new growth in around 10 days as green leaves start to grow and the stunted growth gradually goes back to normal.
