When Do I Switch Nutes?

I just placed four plants in the flowering room yesterday and last fed them two days ago with vegging nutes.
Can I start flowering nutes right away, wait a little, or continue with veg. nutes for the first week or so.

if youre using one formula for the whole flowering, go ahead. if youre gonna break the flower cycle up into three separate feeding parts, do that, too.

thru flower, i use a different formula for preflower, bud production, and ripening. and ill start hitting em with the preflower concoction about 3-4 days BEFORE i induce flowering.

It really depends on the particular strain you're growing. If you're growing an Indica dominant strain with a short flowering period (7-9 weeks), you need to begin weaning your plants off of Nitrogen rather quickly. I usually begin using bloom nutes after about the second week of 12/12. Long-flowering Sativa strains, however, can be weaned off Nitrogen more slowly. Perhaps 4 or 5 weeks depending on the length of flowering required.