Red stems during vegetive stage

I follow the stems of the leaves in veg, If their not a purple trait plant. When I see the stems of the leaves are green in veg, means they are at their perfect nutrient level. As I see the stem of the leaves taking on a little pinky red is when their telling me they need a little bump up in their feed amount. I have followed this rule for many many yrs and it works for me. This only applies in veg stage, not in flowering. Stem of leaves will take on some colour in flower

P-def, but if only at top could definitely be LED. Also, some plants are genetically that way too. several people have tried to fix this, but i don't think they are consistently successful. I recently boosted P 20% and saw some modest improvements, but still red especially where exposed to more intense light. I recently boosted another 15% or so and ran into some slowly progressing P toxicities (6+ weeks to form). So, i'm not low on P, lol. Didn't have deficiencies before the amplification of P, either. so, if oyu boost p and get p-tox, drop back down and just accept the reality of the red petioles. **** ah shit.. you mean leaf stems (petioles)? if your stems (real stems, not petioles) are red or have streaks of red, that is a Sulfur deficiency. (again, could be genetics too)

Can usually happen if the stem is exposed to LED light. Not sure what stage you are at though without a picture.