1 week into flowering, no pistils on preflowers yet. Change to flower nutes, or what?

Depending on the strain your growing, flower initiation can take up to 2-3 weeks and if you are boosting CO2, this may cause her to hold on to veg growth a bit more than normal. Flowering nutrients are just that, for when the plant is flowering. At this stage, I would, and do continue, with grow type nutrients until the first tufts of flowers form, as cannabis does still need nitrogen during the initial stages of flowering. I usually keep with the grow nutrients until they form small "tufts" of identifiable flowers, then switch to half grow and half bloom nutrients for 2-3 weeks, before going to straight bloom nutrients until they are finished, and then giving them just plain water for the last week before harvesting. This method works well for me, others may disagree, but I can highly recommend my method as being safe and effective, with great results and no problems, ever. I have also been doing this for 20+ years, so is a proven method, to me at least! I would also suggest not cutting any leaves off unless they are yellow. Your plant(s) needs her maximum amount of healthy green leaves to be able to produce her maximum amount of energy so that she can then grow her maximum flowers. Cannabis, being the super plant she is, will also re-use stored elements, like amino acids, sugars, carbs etc, that are in her older leaves, to use during flower growth. It is far more efficient to re-use these "stored" elements from her older leaves than it is to grow flowers AND make these vital growth elements from new at the very same time as trying to grow flowers. This is something the defoliation advocates fail to understand. This is why, also, the older leaves on your plants go yellow, despite being healthy and well nourished plants otherwise. Other than these couple of things, just watch out for drop bears! So, remember - maximum healthy green leaves = maximum energy production = maximum growth potential. Hope this helps,....... Organoman.