Tomato Blossom End Rot: Causes & Solutions
The tomato may look healthy on top, but when flipped over, the bottom may be rotten. This is caused by the plant’s inability to absorb enough calcium, which is crucial for protecting the tomato’s outer layer. Without sufficient calcium, the tomato fruit rots from the bottom, a condition known as blossom-end rot. Other vegetables, like peppers, eggplants, and pumpkins, can also be affected by this issue.
Several factors contribute to tomato blossom end rot. Read on to learn more and find solutions.
Calcium Deficiency in Soil
When the soil lacks enough calcium, plants struggle to absorb and transport it to the fruit, resulting in rot. As tomato plants grow, especially larger varieties like beefsteak tomatoes, their nutrient needs increase, and calcium in the soil is gradually depleted. This is especially common in potted tomatoes, where the limited soil volume quickly runs out of nutrients.
To increase calcium in the soil, you can add crushed eggshells, oyster shells, or bone meal. However, these materials take time to break down. If your tomatoes are already showing signs of bottom rot, applying lime to the soil is a faster solution. Just be sure to test your soil first, as lime can raise the pH and cause other nutrient imbalances.
Inconsistent Watering
If you're using nutrient-rich soil or calcium-containing fertilizer and are still experiencing blossom-end rot, inconsistent watering could be the cause. During fruit development, tomato plants need regular and thorough watering. Insufficient or fluctuating moisture disrupts the flow of calcium from the roots to the fruit, leading to rot.
During the flowering and fruiting stages, the soil should remain consistently moist. Watering once a day may be necessary, and in hot weather, twice a day or more may be needed. Some growers may suggest watering less to encourage more fruit production, but this method is only effective during the vegetative stage. After flowering, ensure your plants receive enough water to support fruit growth.
For more precise watering, especially in containers, consider using a drip irrigation system. This method delivers water directly to the roots, ensuring consistent moisture and reducing water waste.
Incorrect Soil pH
If you’ve ruled out the common causes above, an incorrect soil pH could be the next factor to consider. Tomato plants prefer slightly acidic soil, with a pH range of 6.0 to 6.8. If the pH is too high (alkaline) or too low (acidic), the plant will struggle to absorb nutrients properly, even if they are present in the soil.
To check your soil’s pH, use a pH tester or test strips, which can be found at most garden centers or online. If the pH is below 6.0, you can raise it by adding lime. If the pH is above 7.0, sulfur can be used to lower it.
Soil Properties
Soils with good water retention, like loamy soil, are ideal for growing tomatoes because they can hold both moisture and nutrients. However, sandy soils drain too quickly, which leads to rapid nutrient loss and poor water retention.
If your tomatoes are already fruiting, avoid changing the soil, as this can stress the plants and cause damage. To improve water retention, consider mulching with organic materials like straw, grass clippings, peat moss, or sawdust.
Root Damage
Root damage can also contribute to blossom-end rot in tomatoes. For tomatoes grown in the ground, this could occur accidentally during cultivation, such as from a shovel. In potted tomatoes, root damage may happen while fertilizing or moving the plant. Damaged roots cannot effectively absorb calcium, which can lead to bottom rot.
If the roots are damaged, recovery can be challenging. The best course of action is to remove any rotten tomatoes and carefully monitor the plant to see if it recovers. To prevent root damage, handle the plant gently, especially when transplanting, fertilizing, or watering.
