And how to prevent it.
How to Prevent Blossom End Rot in Your Tomatoes
If you’re growing tomatoes this season, you might have heard of Blossom End Rot. Despite its name, it’s not a disease or fungal problem - it’s a physiological disorder caused by a lack of calcium within the plant. Tomatoes that are too wet or too dry can struggle to take up calcium properly, and the blossom end of the fruit is the first to suffer.
Blossom End Rot is a common issue in tomatoes and can also affect eggplant, capsicum and zucchini plants.
Blossom End Rot usually appears as a leathery, sunken blotch at the blossom end of your tomatoes, which can expand across the bottom of the fruit and eventually cause it to rot. While it can be frustrating, the good news is that prevention is straightforward.
1. Add Calcium to Your Soil
One of the best ways to prevent Blossom End Rot is to make sure your soil has enough calcium.
- Before planting: Mix some lime into the soil.
- For potted tomatoes: Try a water and lime slurry around the base, as calcium can easily leach from potting mix.
2. Feed Your Plants Well
A high-quality tomato fertilizer containing calcium will not only nourish your plants but also help prevent Blossom End Rot.
- Apply Tomato Food around the base of your plant - feed regularly for extra support.
3. Keep Watering Consistent
Water deeply and regularly, keeping the soil evenly moist.
- Too much water floods roots and dilutes nutrients, while too little water prevents the plant from absorbing calcium at all.
- Calcium moves through the plant with water in a process called transpiration—think of it like sweating for plants. Leaves and stems get calcium first, and the fruit is last in line, which is why consistent watering is so important.
- If you’re going away, ask someone to water your tomatoes or set up a simple irrigation system to maintain consistency.
By keeping your watering consistent and feeding your plants properly, you’ll give your tomatoes the best chance to grow healthy, juicy, and free from Blossom End Rot.
Quick Tips for Preventing Blossom End Rot
- Mix lime into the soil before planting.
- Use a water and lime slurry for potted tomatoes.
- Apply calcium-rich tomato fertilizers like Brunnings Tomato Food.
- Feed regularly with liquid tomato feed such as Flourish Tomato Food.
- Water consistently - avoid letting the soil dry out or become waterlogged.
- Set up a watering system if you’re away to maintain regular moisture.
By following these steps, you can greatly reduce the risk of Blossom End Rot and enjoy healthy, juicy tomatoes all season long.
