No, when you have an autoflower in veg and then switch to bloom nutrients it's done and cannot be undone, your autoflower is now no longer in veg regardless of size and will never grow in veg again, I learned this the hard way, when i first started an autoflower started to flower as usual but I though I would help it along by adding some bloom base and agent, mistake big mistake, my plant imedietley stoped growing!! It never again grew, I flushed it out and tried to put it back in veg nope, the plant never grew again, with autos timing is everything, all i want is my autos to top off and be in full flower, that's it, this usaly happens between day 50 and 60 depending on strain, however at day 41 my northern lights toped and are in full flower a bit early but they have been in a controlled environment a.c. ect, today I flushed out the food residue from my plants added botanacare pro flower base and Atami bloombastic, I changed the spectrum of my light allso from full spec to full bloom, what I did cannot be undone my plants are now longer in veg and will now forever be in just flower, once you take this step it's for keeps, for better or worse, that's why timing is important, I looked at my 41 day old plants, they all toped, are in flower, and starting to show trichomes so a bit early but ready and once I did what I did it cannot be undone, never try and help an autoflower along by adding flower base and agent until your plants are ready beacuse once you change growing season is over.