When tomatoes, peppers, melons or eggplant end up with a rotten spot on the blossom end of the fruit in summer, the cause was in place long before you found the problem. Here is how the problem develops and what you can do now to prevent it.
Tomatoes, eggplant, melons and peppers all need calcium for healthy development. If they don't have this as they grow, the tissues on the blossom end of the fruit break down.
The problem shows up when there isn't enough calcium in the soil or when the calcium present is tied up in the soil chemistry because the pH is too low.
Also, drought stress or moisture fluctuations can reduce uptake into the plant. Another reason is that overfertilization causes the plant to grow so fast that calcium, which moves slowly, can't keep up. So what do you do?
Start now by testing the soil. A soil test measures the pH of the soil, which should be 6.5 to 6.7. When the soil is too acidic, calcium availability falls off quickly. The test will tell you how much lime to add to raise the soil pH to an ideal level. As a bonus, lime also contains calcium.
Work the lime into the top 12 inches of soil. For this season, look for a lime labeled "fast-acting." Plain, ground limestone can take weeks to react once in the soil.
Avoid overfertilization. Fertilizing during early fruitingespecially with forms of nitrogen made from ammoniacan tie up calcium in the soil.
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Blossom end rot isn't pretty, but at least it doesn't "jump" from plant to plant.
Photo: Jessica Rozmus |
Avoid moisture extremes. Use mulch to keep the soil evenly moist. In lieu of rain, water as needed. Plants need 1 to 1½ inches of water a week while fruiting.
The good news is that BER isn't a condition that spreads from plant to plant. It's all about environmental conditions. If you've done your soil tests and fertilized correctly but are still seeing BER in your plot, a sudden loss of moisture is the most likely culprit.
Roma tomatoes seem especially susceptible. The long, cylinder-shaped fruit may have a spot on the very end, but the rest of the fruit is still usable. That's good to know if you're just using it for sauce. In fact, cutting the affected portion off any affected fruit is fine since BER isn't caused by a pest or disease.
As a last resort, you can spray tomato plants with a calcium solution such as Stop Rot. However, this does not seem to work as well for other vegetables, only tomatoes.
Follow label directions. Generally, you need to spray two to three times a week, beginning when the first blooms appear.
Although spraying is not the best solution, it can help salvage your crop until you can take the other steps mentioned above.