Yellow leaves on several houseplants do not automatically point to one shared problem. This digital checklist kit helps you investigate plant by plant, compare patterns in older leaves and new growth, and consider light, watering, soil drying, care history, and possible pests before deciding what to check next. Use the observation checklist, identification and reference cheat-sheets, care history tracker, and evidence worksheet to organize what you notice; then use the pre-care check and one-change-at-a-time test SOP to guide careful follow-up. Pest inspection and verification checklists help you look for evidence without assuming every symptom has the same cause. Get a practical, repeatable way to assess yellowing and choose a next step—without treating propagation problems as the focus.