Nitrogen deficiency on tomato
A physiological disorder caused by too little nitrogen in the soil, or by heavy rain washing it out. Nitrogen moves freely within the plant — when it runs short the tomato pulls it from older leaves into young ones, which is why symptoms always start at the bottom.
Symptoms
- Even pale-green, then yellow coloring across the whole leaf blade including the veins
- Symptoms starting on the oldest, lowest leaves and working upwards
- Leaf veins and stalks may take on a purplish-red tint
- Small, stiff plants with thin stems and short internodes
- Small, upright leaves that dry and drop early
- Poor fruit set, with small fruit ripening prematurely
What it does to the crop
- Clearly stunted growth and much less leafy growth
- A large drop in yield — fewer trusses and smaller fruit
- A shorter cropping period and an early end to the season
What encourages it
- Light, sandy soils low in organic matter
- Nitrogen washed out of the soil after prolonged heavy rain
- Soil too cold in spring, holding back mineralisation
- Large amounts of straw or sawdust dug in, locking up nitrogen
- No feeding during rapid growth and fruiting
Prevention
- Base and top-dress nitrogen to match the growth stage
- Foliar feed with urea or a compound fertiliser at the first signs
- Build up soil organic matter — compost, manure, green manures
- Split the nitrogen into several small doses instead of one large one
- Test the soil before the season and correct shortages in advance
⚠️ Before you reach for a spray
This atlas is informational and still growing — different diseases can look almost identical. Confirm the diagnosis and read the product label before applying any plant protection product. If you are unsure, ask your local extension or advisory service.
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