How to Prevent Black Spots & Blossom End Rots on Tomatoes

Are black spots appearing on your tomatoes? Learn what causes black spots to appear. Find out what steps you can take to prevent them from appearing on your tomatoes again.

Cause of Black Spots on Tomatoes

If you see black spots on your tomatoes then you are most likely dealing with a condition called blossom end rots. This is a fairly common problem that tomato gardeners may experience.

Blossom end rots tend to occur when the tomato growing season starts out wet. You will start to notice the rot when the fruits are about half their full size. Vegetable and fruits like tomatoes need a health intake of calcium in order to develop. The blossom end of the tomato will start to break down when there’s a lack of calcium.

The shortage of calcium can be caused by a number of factors such as moisture fluctuation, low-pH soil, or the presence of too much fertilizer. While pests don’t directly contribute to blossom end rots, you may want to take the appropriate steps to keep them at bay. Common tomato pests may include flies, slugs, and caterpillars.

Tomato Blossom End Rot Prevention Tips

It’s most likely too late to salvage tomatoes affected by bottom end rots. Here are a few steps you could take to prevent blossom end rots for future tomato crops.

Soil pH Level
The soil pH should not be too acidic or too alkaline. The optimal pH level for tomatoes is between 6.2 and 6.8. This soil condition will enable the tomato plant to take in more calcium.

Fertilizer Usage
Don’t over-do the fertilizer. Too much nitrogen, especially during the early fruiting stage, may tie up the calcium to the soil chemistry.

Moisture Stress
The soil should be kept evenly moist. One way of maintaining an even level of moisture is to apply mulch on top of the soil. Mulch can minimize evaporation from the soil.

Calcium Spray
You can apply calcium spray to tomato plants as a temporary measure. Calcium sprays can be made at home using calcium nitrate or calcium chloride. Combine four tablespoons of either powder with a gallon of water. Pour the solution into a spray bottle and shake well.

When ready, spray the calcium solution on the leaves and stems when the first bloom starts to appear on the tomato plants.