Most tomato problems in the UK come down to a small number of causes: cold, inconsistent watering, too much or too little feed, poor light, or disease. This page is the quick way to work out which one you have. Below is every common tomato problem, how to recognise it, and a link straight to the full fix for each. Start with the symptom that matches your plant, because the same underlying cause often shows up in several different ways, and treating the cause beats chasing each symptom.
Find Your Tomato Problem
Match your plant to the symptom below, then follow the link for the full diagnosis and fix. If more than one applies, work through them in order, because early problems like cold and irregular watering are usually behind the later ones.
Seedlings Tall, Thin and Floppy
Young plants that stretch, lean and grow pale and spindly are short of light and often too warm, a condition called legginess. It is extremely common on early windowsills, and while a leggy seedling can be rescued by burying it deeper when potting on, prevention is better. Full detail in why tomato seedlings go leggy.
Yellowing Leaves
Yellow tomato leaves have several causes, from the natural loss of the lowest leaves, to cold, overwatering, or a genuine feeding shortage. Where the yellowing appears on the plant, and whether the veins stay green, tells you which one it is. Full detail in why tomato leaves turn yellow.
Lots of Leaves but Little or No Fruit
A big leafy plant that will not set fruit is usually a feeding or pollination problem: too much nitrogen drives leaf at the expense of flowers, and in a still greenhouse the flowers may not be pollinated at all. Easy to fix once you know which it is. Full detail in why tomato plants produce no fruit.
Flowers Dropping Off
Flowers that form and then fall without setting fruit are usually reacting to stress: temperatures too hot or too cold, dry roots, or poor pollination. Steady watering and a gentle tap of the flower trusses to spread pollen usually solves it. Full detail in tomato flowers dropping and poor fruit set.
Sunken Brown Patch on the Bottom of the Fruit
A dark, leathery, sunken patch on the base of the fruit is blossom end rot. It is not a disease and not something to spray. It is caused by irregular watering blocking the plant from taking up calcium, and the cure is consistent watering, especially in pots and grow bags. Full detail in caring for tomato plants and watering.
Split or Cracked Fruit
Tomatoes that split are almost always reacting to uneven watering: a heavy soak after a dry spell makes the fruit swell faster than its skin can stretch. The fruit is still fine to eat, and steady watering prevents it. Full detail in watering tomatoes consistently.
Brown, Blotchy, Fast-Spreading Leaves and Fruit
Brown patches that spread quickly across leaves, stems and fruit in warm, wet weather, giving a scorched look, are late blight. This one is serious and there is no home cure once it takes hold, so recognising it fast and acting to save the crop matters. Full detail in tomato blight.
Other Marks, Spots and Diseases
Not every mark is blight. Tomatoes get a range of other leaf spots, moulds and viruses, most far less serious, and telling them apart stops you panicking or over-treating. Full detail in tomato diseases in the UK.
Plants Stalling or Wilting in Heat
Plants that wilt in the afternoon sun but recover by evening are simply thirsty in the heat and need more consistent water, often twice a day in a hot greenhouse. Persistent wilting that does not recover is a watering or root problem worth investigating. Full detail in tomato plant care in hot weather.
Slow to Ripen
Green tomatoes that hang for weeks without colouring are usually just waiting for warmth, or the plant is carrying too much fruit and foliage. Removing lower leaves, stopping the plant in late summer and patience all help, and any that refuse to ripen make excellent chutney. Full detail in growing tomatoes successfully.
The Causes Behind Most Tomato Problems
Look down that list and the same few culprits appear again and again. Inconsistent watering causes blossom end rot, splitting, flower drop and wilting. Cold checks seedlings and stalls young plants. Too much nitrogen gives lots of leaf and no fruit. Poor light makes seedlings leggy. And warm, wet, airless conditions invite disease. Fix those underlying causes, water steadily, feed sensibly, give plants warmth and light and air, and most of the problems on this page never appear in the first place. My guides to caring for tomato plants and growing tomatoes cover the good habits that prevent the whole list.
Frequently Asked Questions
What is the most common tomato growing problem?
Inconsistent watering is behind more tomato problems than anything else. It causes blossom end rot (the sunken brown patch on the fruit base), splitting, flower drop and wilting. Watering steadily and evenly, especially for plants in pots and grow bags, prevents all four.
Why does my tomato plant have lots of leaves but no fruit?
Usually too much nitrogen feed, which drives leafy growth at the expense of flowers, or poor pollination in a still greenhouse. Switch to a high-potash tomato feed once flowers form, and tap the flower trusses gently to spread pollen. It is one of the most common and most fixable tomato problems.
What is the brown patch on the bottom of my tomatoes?
Blossom end rot. It is not a disease and not something to spray for. It is caused by irregular watering stopping the plant taking up calcium, so the fix is consistent watering rather than any treatment. It is far more common in containers and grow bags, which dry out fast.
How do I know if my tomato has blight?
Late blight shows as brown, blotchy patches that spread fast across leaves, stems and fruit in warm, wet weather, giving the plant a scorched look. It moves in days rather than weeks. Slower, more localised marks are usually a less serious disease. There is no home cure for late blight once it takes hold.
Why are my tomatoes not ripening?
Usually a lack of warmth, or a plant carrying too much fruit and leaf. Remove the lower leaves to let light in, stop the plant by pinching out the top in late summer so it puts energy into ripening rather than growing, and be patient. Any that will not ripen before the cold make excellent green tomato chutney.
A Sensible Place to Start
If your tomato is in trouble right now, find its symptom in the list above and follow the link for the full fix. If you are reading this before anything has gone wrong, which is the better time, know that the great majority of tomato problems trace back to just a few things: water steadily and evenly, do not overfeed with nitrogen, give plants warmth, light and airflow, and keep an eye out for blight in warm, wet spells. Get those right and most of the problems on this page simply never happen. Tomatoes look fragile, but they are forgiving once you understand the handful of things that actually matter.