Green is a color that is almost universally associated with plants — for good reason. The green pigment chlorophyll is essential to plants’ ability to generate food; but what happens if they don’t have enough of it? New work reveals the complex, interdependent nutrient responses underpinning a potentially deadly, low-chlorophyll state called chlorosis that’s associated with an anemic, yellow appearance. It could usher in more environmentally friendly agricultural practices — using less fertilizer and fewer water resources.