Purple Stems

I've read through quite a few topics and just wanted to make 100% sure what the problem is.


Indoors under a 400w HPS. Transplanted, then didn't change for over 1.5 weeks until switched to 18/6 which is showing a small amount on new growth.

The stem is a typical green up to the first two leaves then ALL the stems/branches are a deep purple from then on.

There is a small amount of new growth on each plant - more on some than others but they all have the same colouring issues.

*no camera atm sorry guys*

Cheers.

ID say its due to them getting cold.

Yes, its cause at night when the hps is turned off the temp drops.
Just get a temp and see what it is at night. If its like anywhere for like 50-70 at night, you might want to get a space heater or something of the sort.

Ok thanks for that, I thought it was the problem.

I leave the light on through the night and turn it off during the middle of the day.


Might buy some sort of temperature type heater thing that maintains a constant temp if I can afford it.

According to "Plant Problems" forum, purple branches may also be a sign of sulfur deficiency (sulfur is not included in many standard fertilizers). By the way, it's normal for some strains to have purple discoloration on the stems and branches.

I have the same problem:

My plants are solidly that colour throughout. Not just hints of purple, solid purple stems.


I have read elsewhere that sulphur deficiency can cause this though, let me know if you manage to fix it.. I've also read that a lot of strains have hints of purple on their stems, maybe that's your strain?