Does UVB cause purpling? What else?

[OttawaGreen]

Does UVB supplementation cause plants that were not formally purple to turn purple?
Also when people say that low temperatures cause that, how low? I am hitting 17°C at night which is about 63 Fahrenheit I think. That's not low enough for purpling is it?
I have been growing these chocolope for many grows with HPS with higher temperatures and no UVB, they have never turned purple before. Now I have switched to LED and UVB and the temperature has come down and just today after 8 1/2 out of 10 weeks of bloom they change this color. Otherwise seem very healthy. Check out my journal in signature for more information.

Do you guys that use UVB supplementation find that your plants turn purple when they didn't before? It's seem the trichomes on the tops of my leaves were turning Amber and purple from early on

 

[Tejasdirt]

I was getting this also
Temps 68-72f
Led light
I don't have supplemt UV
BUT THE LED light has added uv
For me it turned out to be a mag def
Started cal mag and it has stopped progressing
And in some places started regressing (purple ing)
My first led try
So I am no expert.......yet.
Peace

 

[OttawaGreen]

I just googled marijuana magnesium defficiency again and I do not see anything like that on my plants they are very healthy.
Purple colour came on for me right after adding uvb and I shut uvb off for a bit ends no change. Turned it back on and purple came on hard especially on parts closest to uv.
I think it is uvb for me...
Either way my buds are looking great with 7-10 days left

 

[OttawaGreen]

I am pretty sure my Purpling was caused by uvb as it was not in the middle where the most uvb is given when the light mover pauses at the ends. Left it on anyway and now middle leaves have turned darker than purple with brown spots. I think they have uv burn. So maybe there is such a thing as too much ;-). Have turned off uvb for now. Perhaps last three weeks would be better if you have full diverge close to plants like I do. If it is far away or you have to move them around manual then maybe all the time is fine. Could also be strain dependant. I expect my sativas are used to more uv...
Oh well need to experiment more.

 

[Bangabong]

Those buds look super tasty! Wish I could give you some help, but I am in my first LED grow and I don't know squat. Been very easy so far.

 

[GoodLuck]

From what I have read, other than a Mag def, purpling happens because of the presence of Anthocyanin's, a water-soluble vacuolar pigments that may appear red, purple, or blue depending on the pH. It can appear through stress, which is what the UVB lamp accomplishes. It comes down to genetics, and really understanding it isn't so much that it "turns" purple as it is the purple is always there it is just the green leaving, at the end of a plants life cycle, the chlorophyll breaks down and the purple shows through better.

This is also how it is possible to breed a purple plant, by only selecting plants high in the Anthocyanin pigment.

The same things happen to trees in autumn chlorophyll beaks down and the other colours show through, and the diversity you see in the country side is the representative of the diversity in the gene pool and environmental conditions of the trees on that particular part of the earth at that moment.

 

[OttawaGreen]

Thanks for the interesting info!

If I shine the uvb on areas that do not usually get It like bottoms of fan leaves or popcorn buds they fill up with tricomes like never before without the uvb. Popcorn bud with uvb:

 

[OttawaGreen]

Leaves with uvb

 

[OttawaGreen]

That was what it looked like for a bottom bud to be hit with uvb for the first time. Look at how the too buds
Look. A little purple and amber on all leaf surfaces before the actual bud was ready

 

[GoodLuck]

Very cool effect, my mouth is watering over here...

 

[GoodLuck]

Did all of your Chocolopes do this?

 

[OttawaGreen]

They never have before I added uvb this grow.
On this grow they both did, but not everywhere only where the uvb was strongest

 

[GoodLuck]

I pulled out my UVB last night after reading your thread, I bought 4 of them a while ago from a petshop but I never did use them. So how long did it take for you to see the difference?

 

[OttawaGreen]

Saw a difference within a week. Saw Purpling after 5 weeks of heavy uvb

 

[GoodLuck]

well I have of one of my uvb lamps burning away, hooked it up last night hope I don't fry a plant lol

 

[OttawaGreen]

I predict you will see a positive change within 5 days.
Report back to us in 5 days please

 

[GoodLuck]

Ya I will take a picture I already have the before I posted her already. But I will post the two together, just so you know I predict more frost rather than Purple, she is already a real deep green Indica Cross.

 

[OttawaGreen]

Yes more frost is what I meant . Purple was Unexpected

 

[GoodLuck]

If it is close to chop time then that would explain the purple as well.

 

[OttawaGreen]

Not on these it wouldn't. Never been purple for all ten grows before this.