Cannabis is a textured plant. Between its glistening trichomes and vibrant red hairs, interacting with weed is an entire sensory experience (even before you smoke it). 

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Chances are you already know that those sticky trichomes are cannabinoid factories. But what’s the deal with those red hairs? 

Some say red hair on weed is a sign of high-quality cannabis while others say it means the weed was harvested too late. Keep reading to find out why weed plants grow those red hairs and what they tell you about your bud.   

Plant Anatomy: Cola

Picture a mature female cannabis plant. The cola (the flowering part of the plant) is seated at the top of the plant in all its fuzzy, colorful glory. If you zoom into the cola, you’ll notice a few of its more visible features:

  • Trichomes – tiny, crystal-like structures coating all parts of the plant
  • Bract-covered pistils – hairy sex organs forming out of the calyx 
  • Stigmas – the white, yellow, brown, or red hairs on cannabis 


Without any magnification, trichomes look like white, clear, or amber crystals covering cannabis flowers and sugar leaves. A magnified view of trichomes will show you the picture of semi-translucent, mushroom-like structures. 

The kief you collect at the bottom of your grinder? That’s just a cannabinoid-rich stash of trichomes. Trichomes are cannabis’ natural storage containers for all the chemicals that make the plant medicine. Trichomes generate terpenes, flavonoids, and cannabinoids. That said, the more densely coated your bud is with trichomes, the more potent your cannabis is likely to be. 


Pistils are covered by a bract, a small, green leaf. When looking at a pistil with the naked eye, you’ll see a small, teardrop-shaped structure with a protruding white or red hair. Cannabis colas are comprised of clusters of many pistils.  

The pistils are essential to the female cannabis plant’s anatomy. They’re also the part of the plant most densely covered in trichomes. Pistils are sex organs containing an ovule and those multi-colored hairs you’ve been wondering about. For the cannabis plant, the pistil is the key to reproduction. For cannabis enthusiasts, the pistil is the medicinal powerhouse.    


The stigmas are the white, yellow, red, or brown hairs that grow out of the cannabis plant’s pistils. The color of the stigma can indicate a plant’s growth stage and potentially its harvest readiness, too (we’ll talk more about that later).  

So why do stigmas exist on the cannabis plant? They’re kind of like fishing poles. Their extended length allows them to catch pollen from male cannabis plants. Once the stigmas collect pollen, the female is pollinated and begins to use her energy to create seeds. 

Unless you’re intentionally trying to produce seeds, aim to avoid fertilization. The best way to do that is to keep your female plants locked away from your male plants. As soon as you realize you’ve got a male plant, remove it to avoid pollinating your entire garden and ending up with seedy buds and minimal medicinal potency.     

Do Red Stigmas Mean It’s Time to Harvest?

The short answer is, “maybe.” 

The color of your weed’s stigmas will change as the plant matures. When your plant’s buds first emerge, you’ll likely see white stigmas peeking through their immature pistils. Between 30- and 40-days following bud formation, the stigmas will darken to a yellowish color.  In another 30 to 40 days, most of the stigmas will have darkened from their original white color. 

But different cannabis strains produce differently shaded stigmas. Some stigmas will never turn red at all, remaining yellow or becoming brown instead. In that case, you might end up waiting until long after your plant’s ideal harvesting point if you’re holding out for red hairs to appear all over your cola. No matter their final shade, the best practice is to wait until at least 80 percent of the stigmas have darkened from white to either yellow, brown, or red before harvesting.

Pro Tip: Watch for Trichomes (Not Red Hairs)

There’s a better way to determine when your cannabis plant is ready for harvest than waiting for the appearance of lots of red hairs, though. 

Some growers say that the most important sign that cannabis is ready for harvest is in the appearance of the plant’s trichomes rather than its stigmas. Clear, glass-like trichomes are indicative of an immature plant. Buds harvested at this stage will not be as chemically rich as they’d be if you waited a few more weeks. 

The best time to harvest a cannabis plant is when the trichomes take on a cloudy, milky, or amber hue. At this point in their growth, the trichomes have reached optimal potency (though it’s likely that some of the cannabinoids are already beginning to degrade). 

The milkier in appearance, the younger the plant and the more THC in the trichome. Amber trichomes are still loaded with THC, but degradation has probably begun. At the same time, the other cannabinoids in the trichome are more mature. 

Ultimately, the best time to harvest will depend on the individual cannabis strain and the growing conditions you’ve provided for your plant. As you gain experience growing your own weed, you’ll become more familiar with when to harvest your plants, when to wait, and when it’s been too long. 

Does Stigma Color Indicate Quality?

Despite what some may believe, stigmas aren’t the most crucial indicator of weed quality. Lots of stigmas may point to the production of many pistils, which means you’re probably looking at a densely packed cola full of flowers. Although a dense cola may indicate powerful, high-quality medicine, the stigmas aren’t the real tell. 

Grab a magnifying glass and look for the presence of lots of milky or amber trichomes. Bunches of red (or orange, yellow, purple, or blue) hairs on a cannabis plant add an aesthetic appeal to weed’s funky look. But if you want top-tier bud, make sure it’s sticky with lots of trichomes.