My Tomatoes Are Wilting & Rotting on the Vine - What Is Wrong?

Blight

• Fungus can cause tomato fruits to wilt and rot early or late in the season. Alternaria solani is the fungus responsible for early blight, a condition that usually occurs after an abundant fruit set. This fungus starts in the foliage and spreads to the green fruits, causing them to rot and drop before they reach maturity. Phytophthora infestans is a fungus that causes late blight in tomato plants. This condition is most common during moist, cool weather. Spots on the affected fruits have a greenish-gray appearance. As the spots spread, they create a rough, dark surface over the fruits. Good soil drainage helps minimize the risk of blight. Watering early in the day provides ample time for moisture absorption, reducing the conditions necessary for fungal growth.

Canker

• Canker is a bacterial disease that first appears as wilting around the edges of tomato leaves. The bacterial infection starts in the lower segments of the plants and spreads upward, causing tiny raised blisters on the fruits. Along with the unripe fruits, the bacteria can cause the stems and vines to wilt and die. Removing dead vegetation and disinfecting gardening tools helps limit the spread of canker diseases.

End Rot

• Blossom end rot is common in tomato plants and usually occurs in response to a calcium deficiency in the soil. Blossom end rot causes the formation of dark spots along the bottom sides of the fruits. Depending on the extent of damage, cutting off the affected ends may allow you to use the remaining fruit. Fluctuating soil temperatures and providing too much nitrogen can lead to this calcium imbalance.

Prevention

• Carefully monitoring the moisture and soil conditions can help prevent fruit rot in tomatoes. Tomato plants require well-drained loamy soils in sunny areas. Keep the soil around a tomato plant's roots evenly moist, rather than letting the soil dry out between deep watering sessions. Using a fertilizer that is high in phosphorus, such as 4-12-4, will encourage an abundant harvest of healthy fruits.