Yes, it is blossom end rot. It is casued due to the lack of calcium in the plant. This occurs when the tomato plant experiences periods of wet soil and very dry soil. A balance needs to be maintained for roots to proeprly absorb calcium from the soil. Tomato plant needs evenly moist to properly absorb the calcium to promote the fruit production. Add plenty of composted materials to the soil, this will help retain moisture and prevent the roots being exposed to overly dry soil. Avoid letting the soil dry out completely between waterings. Uneven watering seems to be the biggest contributor of blossom end rot. Maintain a PH of 6.5 for optimum calcium absorption. Bone meal or manure will increase the calcium in the soil.
Avoid high nitrogen fertilizers as these may bind the calcium and prevent absorption. Choose organic nutrients high in phosphorus and potassium for healthy tomatoes.
Last edited by afgreyparrot; Aug 24th, 2012 at 10:49 PM.