Brown Spots on Homegrown Tomatoes

There are a number of fungi, bacteria and viruses that can leave your tomatoes with brown spots. Some leave the fruit itself spotty and some attack the leaves or stem. Prevention is the best medicine. Plant and maintain the tomatoes in the best conditions and watch them carefully. Some problems can be solved by catching them early. Brown spots do not always make the fruit inedible, but keep any diseased or pest-infested plants out of the compost heap.

There are three most likely suspects when brown spots appear on your tomatoes. Bacterial speck or spot is a bacteria that causes spots on the leaves and fruit. The specks on the fruit are raised and look like small bumps or scabs. The leaves might have larger brown spots or specks. If it comes late in the season, the fruit will be usable, but early on it may destroy most or all the fruit. Bacterial speck and bacterial spot are spread when you water from overhead instead of at the base of the plant. Rain can also be a factor.

If a smoker is in the garden, either smoking or touching the fruit, your tomatoes may develop brown spots called tobacco mosaic. It stunts the plant and mottles the leaves. But the fruit gets spotted brown and sometimes streaked with brown. Even using tools that have come into contact with plants affected by tobacco mosaic virus can spread the disease. Destroy these plants and caution smokers to be careful in the tomato patch.

Early blight is a prime contender for creating brown spots. This fungus first yellows and browns leaves. The spots on leaves at first may look like concentric circles. If you catch it early, remove the damaged leaves and use a fungicide on the plant. Unchecked early blight will get worse during the warmer months. Mulching plants goes a long way toward prevention because the fungus is found in the soil and mulch prevents them from being blown onto the plant.

All tomato conditions can be abated or prevented by keeping a clean garden. That means mulch plants, don't let moisture set on leaves, add organic compost to soil and keep weeds down. Don't plant tomatoes too close together because they need air to circulate between them. Keep watering patterns consistent throughout the growing season because fluctuations in moisture can invite disease.