Blossom End Rot in Hydroponic Tomatoes: Causes, Prevention, and Fixes

Blossom end rot in hydroponic tomatoes is primarily caused by a calcium deficiency in the developing fruits. While calcium may be present in the nutrient solution, the deficiency often arises from factors that inhibit its uptake and transport within the plant. Here are the common causes:

1. Fluctuating Moisture Levels

Inconsistent watering schedules or improper nutrient solution delivery can disrupt calcium transport, leading to localized deficiencies in the fruit.

2. High Humidity

Excessive humidity reduces transpiration rates, which limits the plant’s ability to pull calcium from the nutrient solution into the fruit.

3. Imbalanced Nutrient Levels

Over-supplying nutrients like potassium, magnesium, or ammonium can compete with calcium uptake, causing a relative deficiency.

4. Rapid Plant Growth

Sudden bursts of growth can demand more calcium than the plant can supply, leading to deficiencies in developing fruits.

5. Improper pH Levels

A pH level outside the optimal range of 5.5–6.5 can hinder calcium availability in the nutrient solution.

6. Inadequate Root Health

Root damage or disease reduces the plant’s ability to absorb calcium, even if it’s present in sufficient quantities in the solution.

How to Prevent Blossom End Rot in Hydroponic Tomatoes

Maintain Consistent Moisture Levels: Ensure even water and nutrient solution delivery with a well-functioning hydroponic system.
Monitor Humidity: Aim for moderate humidity levels (50–70%) to support transpiration.
Balance Nutrient Solution: Avoid over-fertilization with competing nutrients and ensure sufficient calcium is included in the mix.
Optimize pH: Regularly check and maintain a pH level of 5.5–6.5 for optimal nutrient absorption.
Support Healthy Roots: Prevent root diseases by keeping the system clean and oxygenated.

Addressing these factors will help prevent blossom end rot and ensure healthier tomato crops in your hydroponic system. Happy Gardening!