Blossom End Rot (BER) is a common affliction that frustrates home gardeners, manifesting as a seemingly sudden decay on ripening fruit. This disorder is not a disease spread by pests or pathogens but rather a physiological condition impacting tomatoes and several other vegetables. The presence of this blemish naturally raises questions about the safety of the fruit, which is the primary concern this article addresses.
Identifying Blossom End Rot
Blossom End Rot is easily recognizable by a characteristic blemish that appears exclusively on the bottom of the fruit, which is the point farthest from the stem. The initial symptom is a small, water-soaked spot that appears while the tomato is still green or just beginning to ripen. This spot rapidly expands into a larger, sunken area that turns dark brown or black. The affected tissue eventually becomes dry, firm, and leathery in texture, giving the disorder its distinctive appearance. This condition is categorized as an abiotic disorder, meaning it stems from environmental or nutritional factors rather than an infectious agent.
Edibility and Safety Concerns
A tomato with Blossom End Rot is generally safe to eat, provided the affected portion is removed. Since the disorder is not caused by a toxic pathogen, the unaffected, healthy tissue of the tomato remains perfectly suitable for consumption. The area of the rot itself is unpalatable, as it can be dry and chalky or slightly mushy, and should be discarded. The safe practice is to slice off a generous portion of the fruit around the dark, sunken lesion, ensuring all discolored tissue is gone. The remaining tomato can then be used fresh, cooked, or preserved.
The main safety risk associated with BER is secondary infection, which occurs after the initial physiological damage. The leathery, collapsed tissue of the rot spot can develop cracks, creating an entry point for common mold, fungi, or bacteria. If the rot spot is noticeably soft, slimy, or shows visible signs of secondary fungal growth, it is best to discard the entire fruit, as the secondary infection may have penetrated deeper than the visible blemish.
Strategies for Preventing Blossom End Rot
Preventing Blossom End Rot focuses on addressing the root cause: an inconsistent supply of calcium to the developing fruit. Calcium is an immobile nutrient within the plant, meaning it can only be transported efficiently with a steady flow of water. Inconsistent soil moisture is the number one environmental trigger for BER, even when the soil contains ample calcium.
Consistent Watering
Maintaining consistent soil moisture is the most effective preventative measure. This means avoiding the cycle of allowing the soil to dry out completely and then over-saturating it. Implementing a deep, consistent watering schedule, such as providing one to one-and-a-half inches of water per week, is recommended, especially as the fruit begins to form.
Mulching
Applying a layer of organic mulch, such as straw or shredded leaves, around the base of the plant helps maintain stable soil temperatures and even moisture levels. Mulching reduces evaporation, which supports the plant’s ability to continuously take up water and transport calcium to the fruit.
Soil Chemistry
Soil chemistry also plays a role in calcium availability. The ideal soil pH range for optimal calcium uptake is slightly acidic to neutral, typically between 6.0 and 7.0. A soil test can confirm existing calcium levels and pH. If the pH is low, incorporating a calcium source like garden lime or dolomitic lime can help correct the balance. If the pH is already correct but calcium is needed, gypsum can be used to add calcium without significantly altering the soil acidity. Over-fertilizing, particularly with high-nitrogen formulas, can also contribute to BER by promoting excessive leaf growth that competes with the fruit for available calcium.