Over the last few years we have seen a massive rise in purple buds on cannabis. Since legislation in Canada and the US, there have been massive advancements in the cannabis market, and one of these is in genetics.
The colour of cannabis can make a real difference in market value and “bag appeal”. Because of this, breeders are now selecting strain and phenotypes that express their colors easier than others.

Growing purple buds can be risky! There is no proof to suggest it is stronger than “green weed” but there is plenty to say it reduces your yield. Lets go over some techniques that turn cannabis plants purple. Then you can decide if it is something you would like to try.
If you have any questions about how to add more colour to your buds, then feel free to ask for help in our cannabis growers forum
What Causes Buds to Turn Purple During Flower?
There are many misconceptions on how to turn buds purple. Lets go over some of these first, as there is really only one good way to turn your buds purple.
Food Colouring:
It should be obvious, that this isn’t a good idea! It will work, but the plant will not be good for smoking. Sure, with enough food colouring added to your feed, you could make your plant whatever colour you want it to be. But it will not be a clean chemical free smoke.
Over feeding Nitrogen of Phosphorus:
As you may have seen in Percy Grow Guides to Plant deficiencies, an excess in some foods will cause your plants to change colour. This isn’t good practise, and I would never suggest over feeding a cannabis plant. Over feeding can lock out other important elements the plant needs, and it will cause other health problems. You will be more susceptible to mould, rot and bugs if your plant isn’t at optimal health. You want purple weed, not weed full of food, and weed thats is discolored because of nuit burn.
Starving the roots of oxygen:
Again, making your plant purposely unhealthy, is not a good way to bring you purple weed. You want to be smoking healthy cannabis plants, not plants that have been treated badly. If you starve your root zone of oxygen, your plant will not be able to eat, and sweat! It will die very quickly under these circumstances.
The Best Way to Turn your Buds Purple

Nature, has been growing weed for far longer than humans have, and nature has the best way to turn cannabis plants purple.
When autumn approaches, trees and leaves start changing colors. Turning red, purple, range yellow, a whole range of colours. This is because of one main element, the change in temperature.
As the night time temperatures begin to drop at the end of summer time, a plant will make less cholrhypl. This is what gives plants and leave their usual green colour. A plant doesn’t just use Chlorophyll for photosynthesis, this is just the most commonly known way a plant produces energy.
Anthocyanins is a pigment found in many plants. It will help a plant covert different wavelengths of light into energy, and protect plant cells from being harmed by the cold environment. This is what encourages the colours of plants to change with the seasons.
Using this information, you can see that the best way to encourage your cannabis plant to turn purple is to make it “think”, autumn approaches. Do this, by reducing the temperature of the night cycle. Temperatures should fall from around 26c, during light on, to below 13c lights off. This comes at a risk of mould and rot, as these are the ideal conditions for mould spores to germinate. Make sure you have plenty of fans to keep the air moving.
How to Avoid Bud Rot and Mould
After a couple of weeks of cold temperatures at ” night” your plant will start to display the colours present by Anthocyanins. Colours still may not show, as purple buds on a cannabis plant is also strain dependent! Make sure you pick the right strain to increase your chances of some purple buds!
Pick the right Strain!
Picking a strain that carries the genetics to turn purple, is a great way to improve your chances of growing purple buds. Some strains are famous for their colours, a list of the is below.
Using one of these strains, and reducing the night time temperatures during the last few weeks of flowering will increase your chances of buds turning purple. There are many more strains, but IMO these are some of the best on the market! Just remember, reducing the temps like this, will cause stress and will probably reduce your yield. It will also raise the risk of but rot and mould taking hold in your grow room.
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Thanks for reading! You can find more information on anything related to growing in our cannabis grow guides. All of our guides are written by experienced growers, and members of our cannabis growers forum. If you have any questions, sign up. It is free, and we are always happy to help!