Growing Tomatoes: Fixing the 8 Most Common Problems

Blossom End Rot

Black, leathery patches on the bottom of fruit. Not a disease — it is a calcium deficiency caused by inconsistent watering preventing calcium uptake. Solution: consistent, regular watering (never let soil dry out completely between waterings). Calcium sprays are secondary — watering consistency is the primary fix.

Fruit Cracking

Radial or concentric cracks in fruit. Caused by rapid water intake after a dry period (rain after drought). Solution: consistent watering to prevent the drought-then-flood cycle. Harvest at the first sign of colour — fruit completes ripening off the vine.

Yellowing Lower Leaves

Normal ageing of the oldest leaves — this is not a problem. If upper leaves yellow: nitrogen deficiency (feed immediately). If interveinal yellowing (veins remain green): magnesium deficiency (apply Epsom salts at 1 tablespoon per litre as foliar spray).

Few Flowers or Poor Fruit Set

Too much nitrogen (lush foliage but few flowers), inadequate pollination, or temperatures above 35°C or below 10°C preventing pollination. Solution: reduce nitrogen when plants are established. Shake flowers gently on warm days to distribute pollen. Shade cloth reduces heat stress.