By Luke Sholl
Browse Deficiencies
Browse Deficiencies
Browse Deficiencies

A copper deficiency in cannabis plants doesn’t happen too often. But when it occurs, it can negatively impact your harvest, since it stops the buds from maturing, when not fixed right away. While a copper deficiency due to a lack of copper in soil or water is possible, it is more likely caused by a pH problem at the roots of your plants that is restricting access to nutrients.

Our guide about copper deficiency can help you identify the signs of it early on, so you can fix it before more damage occurs. Even if you may not be able to save affected leaves that may have turned yellow because of a copper deficiency, your new growth will be fine. Most importantly, your cannabis plant will be able to flower and develop buds without a problem.

Copper Deficiency In Cannabis Plant


When there is a copper deficiency, the leaves of your plant turn dark with blue or purple undertones. As the leaves turn dark, the tips and edges of the leaves will turn a bright yellow or white. The leaves of your cannabis plant can also get a shiny, metallic appearance. Sometimes, the leaves can also roll under when they are affected. When your plants are already into flowering, a copper deficiency can severely affect bud growth. The buds ripen only very slowly or not at all.


Nutrient burn can also start with yellowing leaf tips, but you should be able to tell the both apart. The affected leaf tips from nutrient burn will at some point become brown, dry and crumbly, while they stay bright yellow or white with a copper deficiency. Another difference to nutrient burn is that a copper deficiency will darken the rest of the leaf and sometimes can give them a blueish or purple colour. A copper deficiency can also make the leaves look shiny. The bright yellow or pale-white tips will be in stark contrast to the rest of the leaf.

Not all cannabis strains are equally susceptible to a copper deficiency. Some strains can be more sensitive than others. During flowering, when there is a copper deficiency, certain cannabis stains can develop dark purple or reddish hues on those leaves that are closest to your grow lights.

A copper deficiency during flowering can be a big problem. When leaves are affected by the deficiency, your plant cannot provide the required energy for proper bud growth. It is therefore important that leaves, especially those near the buds, are healthy to ensure optimal yields. It is normal that cannabis leaves are turning yellow and start dying in the late stage of flowering. However, when you spot leaf problems that are unexpected or unusual, they deserve your attention and you should act quickly.THE SYMPTOMS OF COPPER DEFICIENCY VS NUTRIENT BURN


Although a lack of copper and other minerals in your soil or water can sometimes be the reason for a copper deficiency, this is not often the case. It’s much more likely that the deficiency comes from a pH problem at the root zone of your cannabis plant. Because of that, the first thing that you should do, is that you restore a healthy root zone. Start with flushing your plant with pH-balanced water.


For healthy growth of your cannabis plants, the pH level of your water or nutrient solution is extremely important. Cannabis has only a narrow window of a correct pH level where the plants are able to take in nutrients. When the pH level is off, the plants cannot take up nutrients—even if they are present.

One common reason for a pH level that is off are salts and minerals that have accumulated in the soil. “Flushing out” these salts restores the correct pH for a healthy root zone. Flush out your cannabis plants with pH-balanced water that contains the proper mixture of nutrients.

If you grow in soil, the best pH level for your plants is between 6.0 and 7.0. If you grow hydroponically, you should keep your pH level between 5.5 and 6.0.


Besides flushing your plants to restore the right pH level and a healthy root zone, you can do some additional things when you’re dealing with a copper deficiency. In gardening shops, you can find copper fungicides that contain copper sulphate and chelated copper. You can use these to give your plants copper right away. When you supply your plants with greensand, kelp and compost, it can help you with copper deficiencies as well.

Some growers treat a copper deficiency by soaking coins in water and then feeding the water to their plants. This works because some coins such as the 1p and 2p coins in the UK and dimes and quarters in the US are made almost entirely of copper. (Don’t use US pennies since pennies have more zinc than copper). Soak some coins in water over night and use the water on your plants if you’re in a pinch.

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