Plant problems
Yellow Leaves on Tomato
Why tomato leaves turn yellow: watering, nitrogen, pests, or disease, and what to do in each case.
Yellow leaves on tomato are not a single problem: watering, nutrients, root suffocation, or pests. Check if the veins remain green, if there are insects, and if the substrate is soaked or dry as a rock.
Quick Diagnosis
Uniform yellowing in old leaves is usually nitrogen or aging. Green veins and yellow blade indicate iron or pH issues. Irregular spots or veil: fungus. Molasses and ants: aphids. The crop and the stake influence: a fallen plant ventilates worse. General guide: tomato, cultivation, and care.
What to Do
Water deeply and less frequently; do not waterlog. Aerate the substrate with perlite or expanded clay if the pot is compacted. Control aphids and ants (see ants in the garden). Restore verticality with stakes so that sunlight and air reach all leaves.
