NO PANIC. JUST A FEW CLUES.

Let’s figure
this out.

A yellow leaf can mean several things. Start with what you can see and feel, then choose a sensible next step.

This is a starting point, not a diagnosis. Different species can respond differently to the same conditions.

Before you change everything.

Should I water a drooping plant?

Check its soil first. A dry leafy plant and a plant with damaged, waterlogged roots may both droop. Follow the moisture cue for its species.

Will a yellow or brown leaf turn green again?

Dead brown tissue will not recover, and fully yellow older leaves usually will not either. Look for healthy new growth to judge whether your adjustment is helping.

Does it need a bigger pot?

Look for crowded roots and difficulty keeping the root ball appropriately watered. A large new pot can stay wet too long. Choose an appropriate next size and free drainage.

My herb is flowering. Did I do something wrong?

Not necessarily. Cilantro and dill are annuals with a natural flowering stage. Basil can be pinched to encourage leafy growth, but flowering is not proof that you failed.

Useful sources

University of Minnesota · Houseplant pests ↗NC State Extension · Watering and root health ↗