i like to use 2 different charts to refer to. print them off , its always helpful. :)
https://www.bing.com/images/search?view=detailV2&ccid=DAfuMsca&id=6A381C7564BEAC87293716BBE5D66E75CC3272FE&thid=OIP.DAfuMscaGZv4MBmG4Bc16QHaE6&mediaurl=http%3a%2f%2floudclouds.co%2fwp-content%2fuploads%2f2016%2f07%2fmarijuana-deficiency-chart-jorge-cervantes.jpg&exph=2658&expw=4000&q=nutrient+deficency+color+marijuana&simid=608013695329239995&ck=CB930DF16471AEC280E5E72DE3325E93&selectedIndex=2&FORM=IRPRST&ajaxhist=0