all the plants developed very well during veg. stage but at the end had some little signs of nutrient burn. I flushed them and after this I just gave water without fertilizer. now the plants are in flower for two weeks but developed really bad.
EC was around 1 , ph 6-7
See the round, necrotic spots? This is definitely a potassium deficiency.
Plus, the leaf petioles are purple, phosphorus deficiency. They are starving.
You are experiencing a nitrogen deficiency. Along with potassium and phosphorus. The plant is starving basically. So I am guessing when you flushed you threw your ph out of line. So you have a lock out or it's just hungry. My guess is hungry.
during veg. the leaves were dark green and the plants were bushy, now two plants got double the hight but very airy buds. all plants have now lighter green, turning into yellow leaves.