The short answer
Record which leaves changed, when it began, moisture observations and recent changes in location or care. Yellowing can have several causes.
Avoid a one-symptom diagnosis
Iowa State Extension explains that yellowing, browning and leaf drop can involve several interacting causes. Watering problems, temperature extremes, drafts and unsuitable or abruptly changed light are possibilities.
Take a whole-plant photograph as well as a close-up. Keep similar lighting and orientation for follow-up pictures so the comparison is easier to interpret.
Write a short case note
Use these headings: plant identity; first noticed; older or newer leaves; one or several leaves; moisture; location; recent changes. Write “unknown” where needed.
Illustrative note: “Noticed Monday. Two lower leaves affected. Moved from shelf to window last week. Moisture not yet checked.” This does not diagnose a light problem. It identifies one change and one missing observation.
Make advice easier to use
If the problem continues, take the record to a local extension service or horticultural advice desk. Ask what additional observation would help separate possible causes.
This checklist does not automatically mean add fertilizer, water more or water less. Several simultaneous changes make it harder to understand what mattered. If insects or distinct lesions are visible, include clear photographs. This guide does not identify pests or recommend pesticides.
A checklist to take with you
Tick items as you go. Checks reset when you leave this page.
Sources & scope
These original sources support the factual guidance above. Examples, diagrams and observation worksheets were prepared for this guide; they are not reports of hands-on tests.
Source check: October 23, 2026. Plant species and local conditions matter. This is general horticultural information.
Keep reading
Dry on top, damp in the middle: should you water? →How far from a window should a houseplant sit? →