my branches gone purple

i heard it's could be lack of potassium....
what else ?
any solution ?

Purple stems usually are a sign that there is a lack of phosphorus to the plant. This can be from a nute lockout situation or a lack of it being supplied to the plant in an another manner such as poor ferts.

Phosphorus – Second to nitrogen as a limiting factor in most soils, phosphorus is essential for the production of a compound called ATP (adenosine triphosphate) that plays a critical role in turning light energy into the energy of chemical bonds. Phosphorus is also part of several proteins, enzymes and nucleic acids that are vital to all plants. Phosphorus deficiency symptoms show first in the more mature leaves, which turn dark green. At maturity, deficient plants are stunted and often show tints of red or purple colors that are caused by buildup of pigments known as anthocyanins. This condition slows flowering in the plant.
Abundant supplies of phosphorus speed maturity and make large flowers. If excess phosphorus is applied, root growth is stimulated, so if you have a short season, risk overdosing with phosphorus rather than underfeeding.
Sources of phosphorus include rock phosphate, colloidal phosphate, bone meal and super-phosphate fertilizer. I prefer nutrients in their organic form because you have a wider margin of error; you are much less likely to damage your plants with organics than with chemicals. In the case of phosphorus, organic forms are relatively slow to go into solution, the soluble forms that can be absorbed by the roots of plants. Colloidal phosphate becomes available to root more quickly than rock phosphate; steamed bone meal dissolves faster than raw bone meal. If you think you need instantly available phosphorus, then you’ll have to get super-phosphate; one commonly available form is Blood Food, a 0-10-10 mixture. (By law, the three “NPK” numbers on a fertilizer label indicate concentrations of Nitrogen, Phosphorus and Potassium)

so should i fertilize through the leaves with a sprayer ?
if that's nute lockout it's a bitch..how to to deal with that ?

Research it first before you go ahead and call it a (P) deficiency. Look at all the variables. Water Ph, soil Ph, nutrients. Is it some purple strain? I think I read that some where also. What do your leaves look like? Are they showing (P) deficiency? Your in flower I take it?

i have 4 planets , 3 auto's planets that r started to flower , and 1 feminised - which is the one with the purple-ish on it , and it's not a purple strain .
here's a pic , that's what i was able to snap

That's not to bad. I think I'd just keep an eye on it. From what I can see your leaf looks good.

My stems turned purple when my temps went crazy cold at night... bunch of different factors before adding nutes to a healthy looking plant.

yeah i guess it could be a cold problem cause i got an intake fan right next to this planet ,
so i moved her away from there .. hope that's all that was.

Seen it loads on my grows. Never felt like it's particularly harmed my plants.

The strain I got will do that with cold nights but still grows good.