Growers Network was created as a resource for adults in the cannabis industry.

Please verify your age to enter.

How Are White Tips Formed on Cannabis Buds?

Interesting side effect of growing under LED lights for this one grower. Has anyone else seen this happen?
https://www.leafly.com/news/cannabis-101/white-tips-on-cannabis-buds

4 Likes

I’ve had this happen too. But it was under 1000w HPS bulbs. I have a pic but can’t upload. Send me your email or someway I can send it to you if you’d like to seeIMG_0077|281x499

5 Likes

Ahh looks like it did work. I think it’s either some genetic mutation or a nutrient deficiency/over abundance???

5 Likes

Too many photons.

I’ve smoked the chlorotic parts and they didn’t taste good. Kind of flat and popcorny. I’m glad they’ve turned it into a marketing strategy at Vashon Velvet, but I think it would be best to dim the lights.

5 Likes

I agree. Spectrum plays a role as well btw. You will not see discoloration easily with extreme PPFD’s wide spectrum white light.

Unlike what people think, most LED fixtures actually need to be at a the same or more distance as HPS fixtures, because they have a much more narrrow beam, leading to extreme PPFD. The reason those plants don’t burn is due to the low IR content of LED light. Same we see with plasma (not burning at high PPFD).

4 Likes

We have seen white-tips in some cultivation operations that flower under purple LED lights. When cannabis flowers are illuminated with red/blue LED spectrum (usually at higher light intensities), tips of certain buds turn white, possibly due to a phenomenon called photobleaching. Plant photosystems may get overly excited with red/blue radiation, and as a result, excess reactive oxygen species are produced, and they destroy chlorophylls ‒ thus photobleaching. However, under (Fluence) broad spectrum LED lighting systems (even at higher light intensities), white-tips are not produced. We hypothesize that it may be due to plant’s ability to better utilize the light energy in the LED broad spectrum due to the following:
• in addition to red/blue, the intermediate light energy within photosynthetically active radiation (PAR) is absorbed by carotenoids, a main antennae molecule in photosystems I and II. Photosystems absorb light and carry out initial reactions of photosynthesis
• chlorophylls absorb light mainly in the red/blue region. Therefore, light in 500-600 nanometer (nm) wavelengths are transmitted and utilized by photosynthetic cells deeper in the leaves. This is evidenced by the significant relative photosynthetic response in 500-600 nm range (please refer to the action spectrum of photosynthesis)
Therefore, even at the same high light intensity, an optimized LED broad spectrum (Fluence PhysioSpec IndoorTM, for example) provides balanced energy to the photosystems of the top photosynthetic cells, while also driving photosynthesis in inner cell layers.

-Tharindu Weeraratne, PhD

5 Likes