Cannabis Cultivation

Why does cannabis turn different colors?

Have you grown plants that are a beautiful green color, light green, dark green, red, purple or even black and wonder why your cannabis plants do this? There are two reasons why cannabis will turn colors, in this article we will explain why this happens, and how you can actually get your cannabis plant to turn color on it own.  

Some cannabis will turn different colors based on the genetics of the plant. While almost all cannabis plant will change color because of temperatures in the grow space or outside.

Colorful Cannabis Plants
Colorful Cannabis Plants

What are Anthocyanins?

Anthocyanins are present all though your cannabis plants. They are in the plant tissues, flowers and leaves, and roots of the cannabis plant. How anthocyanins will display in the plant are red, blue and/purple and this is also according to the PH in the plant itself. You can actually change the normal PH of a marijuana plants which is typically 5.5 to 6.5 in flower. This will influence the anthocyanins in the plant tissues. When you take the plants in flower and go just outside of this normal PH range one way or the other, it can either enhance anthocyanins or minimize them depending on if you go a bit higher or a bit lower in PH.

One of the most interesting facts about anthocyanins is that they can even be present in the cannabis trichomes themselves, this is what will change you trichome heads, when viewing under the microscope to purple colors.

Anthocyanins in the cannabis plant also are powerful antioxidants and are thought to have anti-inflammatory and neuroprotective properties for humans.

How to change the cannabis plants color with temperatures?

The first and easiest way to have your weed plants change color is to drop the temperatures in your grow room when the light are off. A vital component to cannabis is chlorophyll, this is what helps to make your cannabis plants green. Why is this important to the marijuana plant color? Well, when you place your plants in cold or cooler temperature, this will start to inhibit chlorophyll production in your marijuana plants.  

Chlorophyll is the most dominate pigment is cannabis leaves, this over rides all the other pigments in cannabis and blocks other pigment colors. This is the main reason why you don’t see the other colors till the temperatures drop.

A great way to think about this is when the leaves fall from the trees in the fall when the weather starts to cool off. Those leaves in the colder weather will start to change from green to red, yellow, orange. The exact same thing happens with cannabis plants. Once the temperatures start to fall the beautiful green colors start to fade and you will start to see other colors start to appear on the leaves and flowers of the cannabis plants.

Beautiful Colorful Purple Marijuana
Beautiful Colorful Purple Marijuana

How cannabis changes colors based on plant genetics

A cannabis plant can have less chlorophyll and more anthocyanins because of genetic differences in the plant. This will cause the plant to change color even without cooler temperatures. When the plant starts to flower depending on where these anthocyanins build up in the plant it can change the color of the plant, that why some plants will keep their green leaves and their cannabis flowers will turn a beautiful shade of purple or red.  

Normally plants that will turn colors due to the genes they possess will also turn the flowers colors as well. A plant that turns color because of genes can not be stopped from changing colors unlike plants that have turned color due to a temperature change or other external factor. Green Avenger Seeds sells cannabis seeds called Sour Fruit Cake that will change to a purple color in the fall. 

Purple Cannabis Plant Color

Other Things that can cause your cannabis plant to change color

When a cannabis plant is stressed, it can change its color, things like too much UV radiation hitting the cannabis leaves can cause the plant to change colors. Also, incorrect plant PH can cause the anthocyanins to change the color of the marijuana plant.  

Sometime cannabis can trick you when changing colors

Cannabis can change color because of nutrient deficiencies, access nitrogen can turn your leaves a very dark shade of green, to the point they will look almost black in color.  Some cannabis plants will change colors due to a lack of the nutrient phosphorus; the stems can turn a dark shade of purple when this nutrient is deficient in the plant. In flowering the cannabis plant will use more phosphorus to produce flowers, resulting in the plant turning purple, lilac or even a bit of red shade.

Remember if you have grown a marijuana crop of the same type before and there were no color changes, the plant maybe trying to tell you it is lacing in a nutrient it needs to produce Chlorophyll. Always be vigilant of plant color changes during the vegetative stages of the cannabis plants growth.  

One of the most common color changes to your plant is the yellowing of leaves, this is a sign that the plant is deficient in nitrogen.

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