Blossom End Rot is not a disease or fungal issue in Tomatoes, but a physiological disorder caused by a lack of Calcium within the plant.

Blossom End Rot is so called because it begins as a leathery blotch at the blossom end of the tomato and enlarges across the bottom end of the fruit and then begins to rot.

Prevention is the best cure to Blossom End Rot. Adding some Lime to your soil before planting will greatly reduce the problem as will a slurry made with Water & Lime poured around your plants. This method works particularly well with potted tomatoes as the Calcium will readily leach from the potting mix.

A good quality food will contain Calcium and will also help feed your plants as well as help to stop the disorder. We would recommend a combination of the Brunnings Tomato Food applied around the base of the plant and a regular liquid feed with Flourish Tomato Food. 

Lastly, a regular watering regime is also essential as irregular watering disrupts the tomato plants ability to utilise Calcium.

Plants that are too wet or too dry will suffer, so if you're going away for the summer ask someone to drop in and water your plants on a regular basis or set up a watering system.