Early blight is the most common tomato disease in the home garden, and it is also one of the most recognisable once you know the signs. It starts on the lower leaves as small, dark spots with concentric rings — a target or bullseye pattern — and it works its way up the plant through the season, yellowing and defoliating the leaves until the plant is bare at the bottom and the fruit is exposed to sunscald. It rarely kills a tomato plant outright, but it shortens the season, reduces the yield, and makes the garden look sick. The good news is that it is a disease of conditions you can change: spacing, airflow, watering and hygiene.
This guide explains the symptoms, the conditions that favour early blight, cultural prevention, what to remove, what not to compost, and the control options. If you are not sure the spots on your tomatoes are early blight, the plant disease checker can help you compare, and our late blight on tomatoes guide covers the more serious disease it is most often confused with.
Symptoms
Early blight starts on the older, lower leaves as small, dark brown or black spots, usually with concentric rings inside them — the target pattern that is the best identification clue. The tissue around the spots yellows, the spots grow and merge, and the leaf turns yellow, then brown, and drops. The disease moves up the plant through the season, so by midsummer the lower half of the plant may be bare. The stems can show dark, sunken spots, and the fruit can show dark, leathery spots at the stem end, often with the same concentric rings.
The key difference from late blight is the pattern and the pace: early blight has concentric rings, starts on the lower leaves, and progresses slowly up the plant over weeks. Late blight has water-soaked spots with no rings, a white fuzz on the leaf underside in humid weather, and it can destroy a whole plant in days. If your tomatoes have target-pattern spots on the lower leaves and the plant is still producing, it is early blight.
Conditions that favour it
Early blight is favoured by warm, humid weather, wet leaves, and plants that are stressed or crowded. The fungus overwinters on infected debris and in the soil, and it spreads by spores carried on the wind and in splashing water — which is why the lower leaves, closest to the soil, are always hit first. Overhead watering, rain splash, crowded plants and poor airflow all make it worse. It is most common in midsummer, when the plants are large, the weather is warm and humid, and the lower leaves are shaded and slow to dry.
Stressed plants are more vulnerable: drought, overfeeding with nitrogen, and heavy fruit load all make a plant more likely to be attacked. The fungus can also survive on seed and on the debris of other plants in the same family — potatoes, eggplant and peppers — so rotation matters for the whole family, not just tomatoes.
Cultural prevention
Cultural prevention is the most effective control, and it starts before the disease appears. Space tomato plants generously — at least 60 cm apart, and more for indeterminate varieties — so air moves freely between them. Stake or cage the plants and prune the lower leaves, removing the bottom 30 cm of foliage so no leaves touch the soil, since soil splash is the main way the disease spreads. Mulch thickly to prevent soil splashing onto the leaves, and water at soil level, in the morning, so the leaves stay dry.
Avoid overhead watering entirely, and never handle the plants when they are wet, since the spores spread easily on wet hands and tools. Feed steadily with a balanced fertiliser and avoid heavy nitrogen feeding, which produces soft, vulnerable growth. Choose resistant varieties where they are available — many modern tomato varieties are bred for early blight tolerance, and your local extension service or seed supplier can advise on what suits your area. Rotate tomatoes, potatoes, eggplant and peppers to fresh ground each year, and do not grow them in the same bed more than once in three or four years.
What to remove, and what not to compost
Remove infected leaves as soon as you see them, and put them in the bin or a sealed bag — do not compost them, because the fungus can survive in a cool home compost heap and reinfect the next crop. At the end of the season, clear away all tomato vines, leaves and fallen fruit, and do not leave them in the bed over winter. Do not compost any of it unless your heap reliably stays hot enough to kill fungal spores — and if you are unsure, the bin is the safe choice. Check your local extension service for composting guidance in your area. Wash your hands and tools after handling infected plants, and avoid working with tomatoes when the leaves are wet.
Treatment, in order
1. Cultural control first. Prune the lower leaves, improve airflow, mulch to prevent splash, and water at soil level. Remove infected leaves promptly and keep the plants off the ground. This alone can slow early blight substantially, and it is the foundation of any treatment plan.
2. Remove and isolate. If a plant is heavily infected, remove the worst-affected leaves and, if necessary, the whole plant, rather than letting it become a source of spores for the rest of the bed. Check the neighbouring plants daily and remove any leaves that show the first spots.
3. Copper and other least-toxic options. Copper-based fungicides can protect healthy leaves if applied early and thoroughly, and they are the traditional treatment for early blight. They are protectants, not cures — they do not cure leaves that are already infected, and they need reapplying after rain. Copper accumulates in the soil, so use it sparingly and only when needed. Neem oil and bicarbonate sprays have limited effect on early blight. Always read the label, apply in the evening, and check your local extension service for products approved in your area. Avoid broad-spectrum fungicides as a routine — they harm soil life and beneficial fungi.
4. Know when to stop. Early blight progresses through the season, and a plant that is badly defoliated by late summer will not recover. The honest answer at that point is to harvest what is ripe, remove the plant, and clear the bed, rather than to keep spraying. The spores will be waiting for the next planting if the debris is left behind.
Frequently asked questions
Will early blight kill my tomato plants? Rarely outright, but it defoliates the plant through the season, reduces the yield and shortens the season. A badly affected plant may produce little after midsummer, and the exposed fruit can suffer sunscald.
Is early blight the same as late blight? No, though they are often confused. Early blight has concentric-ring spots on the lower leaves and progresses slowly. Late blight has water-soaked spots, a white fuzz on the leaf underside, and it can destroy a whole plant in days. See our late blight on tomatoes guide for the comparison — late blight is the more serious disease, and it needs a faster response.
Can I eat tomatoes from a plant with early blight? Yes, if the fruit itself is healthy. The disease affects the leaves and sometimes the stem end of the fruit — cut away any affected part of the fruit and wash it well. Do not eat fruit that is badly spotted or rotting.
Should I compost tomato leaves with early blight? No, unless your compost heap reliably stays hot. The fungus can survive in a cool home compost heap and reinfect the next crop. Put infected leaves and vines in the bin.
How do I prevent early blight next year? Space plants for airflow, prune the lower leaves, mulch to prevent splash, water at soil level, choose resistant varieties, rotate the whole tomato family, and clear away all debris at the end of the season. Check your local extension service for resistant varieties suited to your area.
Early blight is a disease where the habits matter more than the cure. Give the plants space and air, keep the leaves off the soil, water the soil and not the leaves, and remove the spotted leaves promptly — and the season will usually last long enough to bring in a good harvest. For the more serious tomato disease, see our late blight on tomatoes guide, and for the related fruit problem, our blossom end rot guide. For general help, use the plant disease checker.