My first grow! purple/reddish stems

A question from a fellow grower:

I’ve noticed a cpl days ago the stems near the leafs started turning purple/reddish, I’m wondering if I have a problem and what I can do to improve its health, or shoud I not worry? I inserting a cpl pics for you too see and hopefully it helps… Thanks and best regards
Miss, ZeB
PS. I have three plants and only one is that way, also its only bag seeds. I wanted to get my feet wet before i bought your huge yeild seed mix.

1 Like

I’m new to this but it looks like a nitrogen problem…u don’t have enough I would increase it in the next feeding…correct me if I’m wrong

Droopy leaves…soil looks dry, but just guessing, is it?

Have you fertilized? Do you test pH? They might benefit from a light feeding, what is the soil they are in?

The plant is stretching for light, move them closer to it…
get a small fan, a very light breeze, very light! on them…it’ll help develop a stronger stem.

1 Like

:;uneasily looking around for the Vets here::


::slips back into the shadows::

1 Like

PH refers to the acidity. Neutral ph is around 6.8 to 7 .Mj likes it a little acidic 6.5ish. I think. I am myself a noob. So I Hope I am giving you the correct info. This is what I believe to be correct Maybe one of the vets will confirm or deny my guess work. Sorry i cant be of more help

1 Like

Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

Strain; Type, Bag seed, or NA

Soil in pots, Hydroponic, or Coco?

System type?

PH of runoff or solution in reservoir?

What is strength of nutrient mix? EC, or TDS

Indoor or Outdoor
Light system, size?

Temps; Day, Night

Humidity; Day, Night

Ventilation system; Yes, No, Size

AC, Humidifier, De-humidifier,

Co2; Yes, No

Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you smile

There are multiple issues which could result in purpling of stems. Genetics, low temp, phosphorus deficiency, nitrogen causing nutrient lockout, pH causing lockout, etc…
This quick questionnaire will help us determine which issue is most likely.
The “sweet spot” for soil pH is 6.5, for Hydro and coco (soiless) is 5.8. You do have a +/-0.5 swing for each, but that will affect different nutrient uptake. For example I run my soil grows closer to 6.5 in growth stage and 6.2 in flower. Where as I keep coco closer to 5.9 in growth and 6.1 in flower.

A pH of 5.8 is best for hydro. It will move and travel a little either way, above or below, won’t hurt. You probably don’t want to let it get below 5.5 as at 5.4 the acid is getting to the point it will damage the roots. And it shouldn’t get much above 6.5, ever. So shooting for between 5.5 and 6.0 for most of the grow is what most people do, and then 6.0-6.5 during the very last parts of the grow.
In soil 6.5 is best, with a range between about 6.2 to about 6.8 and no higher than 7. Looking at pH charts, you can play a little with pH to increase or reduce the availability or uptake of certain nutrients for the plant.


My bad. I was just playing around and asked the question that I knew was coming. Been here long enough to know and anticipate.


1 Like

The plants will be 4wks old Monday, they’re in foxfarm soil, I also use the foxfarm trio for nutes and follow the foxfarm feeding schedule. The temp in my box is 80° day and night. Two 4in fans and C02. The lights: one 300w grow bulb i bought at a hardware store and two 32w cfls, PH 6.0, box size 3x3x2. Also the 2nd plant started the same coloring. I’ve also noticed when feeding the trio and splashes of the mix gets on the leaves it stains em then turns into burns, so after feeding I’ve been rinsing them with water.

maybe phosphorous deficiency, but most nutrient systems formulated with cannabis in mind have plenty and so it is more often a magnesium deficiency and a cal/mag or epsom salt (magnesium sulfate) often is the remedy.

some strains have some purple stems, too, naturally