Wynternight, I started introducing lactobacillus at 2 weeks (I waited until it was clear that all was essentially healed in the vaginal cavity (I'd had no bleeding in over a week etc). My surgeon's standard protocol was a douche of 10% vinegar once or twice a week an I simply would open a probiotic capsule and include it in the douche bulb.
I continued to do this for the duration of time that I was directed to continue the vinegar & water douche and then again when I had a post-op staph infection (that was limited to the external vulva however the antibiotic treatment of course kills off the good bacteria so I felt it wouldn't hurt to be sure I stayed properly colonized :-)).
My pH has stayed neutral - in this we are like post-menopausal women, the vaginas of natal females release glycogen which is what the good bacteria thrive on and it's that metabolism that in turn creates the low pH which keeps the bacteria we don't want from thriving, hence avoiding BV or yeast infection. My neutral pH notwithstanding, it's clear my vagina has had essentially the same odor since about 8 weeks post-op and that for now my lactobacilli friends are here to stay at least for the foreseeable future (I had a vaginal culture done the other day due to some problems with blood coming from my G-spot (aka prostate), a little bit of hangover from having once had male-bits so I'm certain there are no bad actors in my snatch right now :-)).
The person to ask is your surgeon in any case. Mine was fine with what I chose to do, felt it was a good plan.