Why do my geranium leaves turn yellow?

Question

I have my plants on the window sill with light but not direct sun.

Answer 1

The first thing to check is soil moisture. Potted plants often show yellow leaves when the soil is too dry — water is not getting to the leaves — or too wet — roots are damaged so they can’t transport water to the leaves. When you water, pour on enough that you get a runoff from the pot. You don’t need to pour it off if it’s 1/2″ or less. Before you water again, test the soil all the way to the bottom of the pot for moisture. You can use a pencil, dowel, or kebob skewer as if testing a cake; or use a moisture meter. The soil should be very slightly damp.
After you decide if soil moisture is the problem, think about light, soil, and mineral levels. This article has more information: https://www.gardeningknowhow.com/ornamental/flowers/geranium/geranium-yellow-leaves.htm