Can I start using ancient earth nutrient on auto ...

the most important thing is to not hurt the plant, if the plant is fine and healthy and the soil is still pretty much full, you dont really need to feed until flowering time . That's my best advice ! so i would say, "yes" it"s possible but start at 1/4 recommended dose and up the nutrients slightly every time you feed until you see a little bit of burn then go back to the previous level and maintain that level. just make sure you follow a strict feed, water, water, feed water water, feed water water schedule and dont over do it you should be okay. Hope this helps PW ! 🚀