Nitrogen - Yellowing that starts at the leaf tip and moves along the center of the leaf towards the stalk. Yellowing has a triangle pattern.
Phosphorus - Leaves have a red to purple color on the leaf edge moving toward the center of the leaf. Often seen on young plants.
Potassium - Yellowing on the leaf edge moving in towards the center of the leaf. Begins with the lower leaves and moves up.
Magnesium - whitish stripes along the the leaf veins and can have a purple tint on the underside of the leaf.
Copper - Whitish colored leaves on the top of the plant.
Water/Drought - Leaves roll up and have a grayish green color.