If you mean signs a tomato plant or fruit can give you about what it needs, here’s a useful guide:
🍅 Yellowing older leaves: often points to nitrogen deficiency, though overwatering can also cause yellowing.
🍃 Leaves curling: can result from heat, drought, inconsistent watering, pests, or certain diseases.
🌿 Lots of leaves but few flowers/fruits: may be related to excessive nitrogen, insufficient sunlight, or temperature stress.
🟤 Dark, sunken spots on fruit: can indicate disease or physical damage.
⚫ Black/brown leathery patch on the blossom end: classic blossom-end rot, commonly associated with inconsistent water availability and difficulty moving calcium into developing fruit.
🟡 Cracks around the stem: usually indicate rapid changes in water availability or growth.
🌱 Wilting despite moist soil: can signal root problems, disease, or severe heat stress.
The important thing is that one symptom doesn’t always have one cause. For example, yellow leaves don’t automatically mean the plant needs fertilizer. Checking watering, sunlight, pests, soil, and the location of the symptom together gives a much better diagnosis.
