Hi all well i am a new grower and just want a bit of help please. I am growing 3 white widow and 1 sour diesel. they are 3weeks old i have them in 11L pots in soil light mix. running a 400w hps temp 70f-75f. humdity 40%-55% with good air movment. feed is 2.5ml of formulex per 1liter of water and 2.5ml of canna veg per 1liter of water. what i have notcied is that the tip of the leafs have a slight bit of yellow on them could this be i have the nuts to strong.... sorry no pics as phone is broken. many thanks uk grower.