What is Blossom-End Rot?

Blossom-end rot is a common problem in many fruit crops, particularly tomatoes, peppers, and melons. It is a physiological disorder that results in a sunken, dark, and leathery area at the blossom end of the fruit. This is caused by a lack of calcium in the fruit, which can be due to various factors, including uneven watering, low soil calcium levels, compacted soil, or high levels of nitrogen fertilization.

Blossom-end rot can also be exacerbated by high temperatures, drought stress, or other environmental conditions that restrict water uptake by the plant. 

What Plants are Affected by Blossom-End Rot?

Blossom-end rot is a common problem that affects many types of fruit-bearing plants, including tomatoes, peppers, watermelons, zucchinis, and eggplants. Blossom-end rot can also affect other plants, including cucumbers, pumpkins, and cantaloupes.

How to Identify Blossom-End Rot?

To identify blossom-end rot, look for a dark, leathery, or sunken spot on the bottom of the fruit that is usually larger than a quarter of an inch in diameter. The affected area may also be slightly raised and have a tan or brown color. If you cut open the fruit, you may see a soft, mushy texture in the affected area.

What Causes Blossom-End Rot?

Blossom-end rot is caused by a lack of calcium in the fruit, which can be due to several factors, including:

1. Water stress: Irregular watering, drought conditions, or sudden heavy rainfall can lead to water stress, which can reduce the uptake of calcium by the plant.

2. Soil pH: Soil with a pH below 6.0 can reduce the availability of calcium to the plant.

3. Root damage: Any damage to the plant's roots, such as from cultivation or soil compaction, can reduce its ability to absorb calcium from the soil.

4. High soil salinity: Soils with high salt levels can also reduce the uptake of calcium by the plant.

5. Over-fertilization: Excessive amounts of nitrogen fertilizer can reduce the plant's ability to absorb calcium from the soil.

How to Prevent Blossom-End Rot?

Ensure the plants have an adequate water supply and proper soil moisture. This can be achieved by watering deeply and regularly, especially during periods of drought.

Avoid over-fertilizing with nitrogen, as this can increase the risk of blossom-end rot.

Mulching around the base of the plants can help to conserve soil moisture and regulate the temperature of the soil.

Proper soil preparation before planting can also reduce the risk of blossom-end rot. This includes testing the soil pH and nutrient levels and adding any necessary amendments to achieve the proper growing conditions for the plants.