" isn't watering and feeding the same? i give the plants water with food inside every second day now, about 0.4 liter for each plant "

monkeyman - watering and feeding are two entirely different things, depends on who you ask. It looks like you have a serious case of nute burn or over fertilization. Please flush them....... To avoid this in the future make sure you give plain Ph adjusted water every third or fourth feeding/watering. Personally I nute nute water and flush on week 5 of FL and just before harvest. Reason why I flush on week 5 of flower is because I plan on giving extra strength K on weeks 6 and 7. Just my 2 cents......

Happy Growing......