Nico’s Nuggets: Purple Pot – How Does It Happen?

Hi Nico! I recently grew some Granddaddy Purps, but they never turned purple. The buds had the taste and smell, just not the color. I heard flushing it with ice water instead of regular water will change the color. I have also been told that during the last two weeks of flower, a drop in growroom temps will do it. Any advice is appreciated as I’m fairly new to growing and want to blow my patients’ mind. Thanks! – Jaysin Mockspeed via

Greetings, J. Thanks for this week’s question. We actually get asked this one quite often as it seems purple buds are very popular with cannabis smokers. I sometimes wonder if there is a psychological tie between the color of the buds and the flavor that people taste? Many people find that most purple varieties carry hints of grape or passion fruit with them. Of course, flavor has more to do with terpenes, or the essential oils of the plant, and less to do with the color of the buds.

The color of cannabis flowers relates directly to the type of pigments found in the plant leaves. While all cannabis plants are primarily green due to the main pigment we all know as Chlorophyll, some strains of cannabis have been known to turn purple throughout their life cycle, most usually towards the end.

There are a couple of reasons for this occurrence. The first is simply time. After enough flowering time, some cannabis strains turn from green, to dark green, to purple – and sometimes nearly black! Not all strains can or will do this. They must have the genetic code within their DNA for this to happen.

Still, sometimes a known “purple” strain will be grown out and not turn purple – usually to the great dismay of the grower. In this instance, flower time may be the culprit, but barring that, yes, temperatures can also play a significant role. I’m not sure that I would recommend throwing ice into the garden’s reservoirs as that may create a bit too much of a shock for the plants, but typical practices for growers of purple strains is to add a week of flower time and then, for the last two weeks of flower, to lower the dark cycle temps between 6-8 degrees (F). This change in nighttime temp can act as a trigger for the plants’ internal rhythm, indicating to them that the cold (harvest) season is quickly approaching. This will usually bring on the purple hues and dark tinges in cannabis plants associated with those types of genetics. If this doesn’t work, it may be that a different strain variety is needed as not all purple varieties are right for certain environments.

Thanks for reading everyone and remember: Grow… And help the world grow, too!

Got questions? Email ’em over to Nico at and be sure to put “Nico’s Nuggets” in the subject line!


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