I'd like to say that I'm not disagreing with the fact that purple stems may indicate a problem in certain instances, but I do want to point out that I have been growing for several years, indoors and out with soils, soiless, and various hydro setups with much success but I frequently get purple stems on my seedlings within the first week or so after germination. I'd have to say I see this 95% of the time in all mediums I use(soil, RW, peat pots, ect). I keep my PH between 6.2 and 6.8 and most of my indoor plants don't see temps below 75 degrees and don't fluctuate more than +-10 degrees(the outdoor plants being an exception) IMO, I feel purple stems in the very early stages are completely normal and no reason for alarm. I've killed many seedlings being overly concerned with nute defiencies and trying to compensate when the seedling is much too delicate to handle any kind of nutrient. I have tried many times to avoid it but it seems to be prevalent in most of my plants for the first week or so. also used different strains, lighting, moisture variences and it always seems to happen but with no problems later on. I'm not trying to say that anyone is wrong but rather to invite you to share your experience and perhaps gain a greater understanding of this issue. By the way, yes this is my first post here but I noticed this was a popular item for discussion and debate, so sorry about the long post but if anyone has anything they like to add, I'd love to hear it.
Pappy
Early on in the plants life I would have to agree Tiger. Welcome to GK BTW. However as the plants mature and are ready to flower red/purple streaks in the mainstem I know for a fact require an increase of phosphorus in their diet. I've seen the effects of not adding any and the effects of giving the plants more during flower and the outcome is amazing to say the least. It's not something that is an exact science, but it's a good indicator that something is not right. Purple leaf stems are not an issue in my opinion though...that is perfectly normal.
