Düngen

You should be feeding every time you water if you want to use liquid nutrients, secondly I would not use a ratio of 0.8ml/L I would look into getting a EC pen and managing it that way. EC is universal and will let you know how strong the feeding solutions concentration is. Autos also don't feed as much as photoperiod plants so giving them to much can cause them to go into shock and flower early. it is said anywhere from 1/2 to 1/4 strength is needed for autos. I would also not be topping autos as they don't normally have the time to recover from the stress. The extra stress can also cause them to go into early flower. Remember to get a good amount of runoff to prevent buildup. Good Luck!