Sunflower Leaf Stems Are Splitting Open

Question

The stems of the leaves on my sunflower plant are splitting open with these small black coffee ground type things piled up coming out of it. What the heck is it, and what can I do to get rid of it?

Answer 1

This can happen when watering is not even. Normally you see this when you have a long period of dry heat followed by a sudden large amount water, either from manual watering or a rainfall.

The plants will be fine and should keep growing.