Blossom End Rot is a consequence of a calcium deficiency of a plant, affecting tomatoes, melons, cucumbers, squash, and peppers. Blossom End Rot doesn’t spread between plants and isn’t a condition that can be corrected by using pesticides or fungicides. When Blossom End Rot first begins, you’ll notice a softening of the fruit in a small spot at the blossom end (end opposite the stem). The spot will become brown and watery, enlarge, darken, and then turn black and flattened.
Photo by Chris Pagliarulo & Gene Giacomelli; UVM Center for Teaching and Learning DSpace Repository
Causes of Blossom End Rot
- It can be brought on by sudden drought when the roots of the plant can’t bring water and calcium to the developing fruit.
- Overwatering and downpours can leach calcium from the soil.
- Installing plants in substandard conditions can also bring on End Rot by impairing the plant’s ability to establish an adequate root system.
- Soils with an overabundance of salts can bring on rot because salts will diminish the availability of calcium.
- High nitrogen plant food can make the problem worse.
How to Avoid Blossom End Rot
- Use a mix of soils and composts for planting, which are well draining and aerated so plants can easily develop healthy roots. If soils are too heavy, roots may have a difficult time establishing themselves.
- Don’t rush tomato growing by planting in colder soils. Wait until temps are warm enough to plant tomatoes out. When planted in cold heavy soil, tomatoes have a very good chance of developing Rot.
- Make sure to check watering when the weather is hot or there are drying winds present.
- Mulching around plants can help by keeping moisture near the roots.
- Use food that’s high in superphosphate and low in nitrogen and you’ll lessen the chances for Blossom End Rot
What to do Once End Rot Starts
- Once the problem has begun, you can use Bonide Rot-Stop, which is calcium chloride sprayed on the foliage; however, nothing will replace good tomato growing practices.
- Pick affected fruits so the plant can send energy to healthy fruits.