Is There a Dark Spot on Your Plant? It Could Be Blossom End Rot
If you see a large circle on the blossom end of a fruit or vegetable in your garden, it could be blossom end rot. The circle starts out as a slight water-soaked area and then transforms to dark brown or black in color and sunken or leather-like in appearance. It’s important to remember this is a physiological disorder, not a disease. As the fruit or vegetable continues to grow, the spot darkens further before eventually covering its majority. This is due a calcium imbalance within the plant and is a common garden problem for tomatoes, peppers, watermelon, squash, apples, carrots, cucumbers, and eggplant.
Left: healthy tomato Right: Tomato with blossom end rot
Fruits and vegetables can get blossom end rot if they lack adequate transportation of calcium. Calcium helps with normal cell growth. Blossom end rot also occurs when there are wide fluctuations of moisture, which reduces the uptake and movement of calcium into the plant. When there is more demand for calcium than the plant can handle, it can lead to tissue breaking down. Calcium deficiency can be a result of water shortages, poor uptake of calcium through the stem, or too much nitrogen in the soil/fertilizer.
It is fairly typical to see blossom end rot the most on early fruit, but as the season progresses, the effects should lessen and the plant should continue to grow like normal. If blossom end rot is still present throughout the season, it helps to remove the affected fruit so the plant continues to blossom normally.
If the issue is persistent, you can try multiple different things: test the soil, adjust how much fertilizer you are using, avoid moisture stress, spray plants with a calcium solution that is made specifically for this disease, and add lime to the soil. Vegetables grow best in soil where the pH level ranges from 6.2 to 6.8. However, if blossom end rot continues to be an issue, it helps to make sure the pH level is a little higher than normal, about 6.5 to 6.8 by adding ground limestone, which also contains calcium. Some fertilizers and soil amendments also contain calcium. ARBORChar™ All Purpose Grow and Root, Flower & Fruit contain 6% and 10% calcium along with a variety of other nutrients needed for optimum plant development.
Prevention is the best medicine as the saying goes, so make adjustments now to your soil and watering practices to help keep blossom end rot from affecting your plants. Use mulch and set up a drip watering systems to keep the soil evenly moist. You can also try not to over-fertilize because too much nitrogen can tie up calcium in the soil chemistry. Spraying tomato plants with a calcium solution for blossom end rot is not a long-term solution, but it can be an interim step before you take the other actions.
Have you experienced blossom end rot? What actions did you take to battle it? For more options to battle this problem in your garden, visit Arborjet.