Prevent blossom end rot in tomatoes by testing the soil, adjusting the soil's pH, adding calcium to the soil, and watering the soil correctly. You must also mulch and fertilize the soil properly.
- Test the soil
Get a soil sample for testing. Preventing blossom end rot in tomatoes requires a soil pH of 6.5 to 6.8. Test the soil early in the year to allow time for results and to give any soil additions time to be effective.
- Adjust the soil's pH
Based on the soil test, apply the recommended soil additions. Lime is often suggested to increase the pH. Use a fast-acting lime if applying it in the early spring. Ground limestone can be used during the fall or winter because it takes time to work into the soil.
- Add calcium
Calcium helps fight blossom end rot. Lime is a good source of calcium, making it a doubly beneficial addition to tomato gardens. Egg shells, either in compost or crushed and worked into the soil directly, also add essential calcium.
- Water correctly
Before tomatoes begin to flower, let the soil get a little dry. This encourages a deeper root system, which allows better calcium absorption. After flowering begins, keep the ground evenly moist. Tomatoes need 1 to 1.5 inches of water a week. Monitor rainfall to avoid over-watering.
- Mulch and fertilize properly
Use mulch to prevent moisture loss. This is crucial in hot climates, where daily watering may be needed. Don't over-fertilize. Avoid adding too much nitrogen to the soil because it hinders calcium uptake.