Hi, I have Roma tomatoes growing at the moment - do them every year. We feed them reguarly with both tomato food and seaweed spray, along with constant watering. I also companion plant with marigolds and have no bugs or caterpillars on the plants. I've noticed that on some of the fruit, they look perfect with no blemishes, colour consistent through and firm to touch, yet when I cut them open the centre where the seeds are is all rotted. Not all of them are like this. Any ideas on what would be causing this? Cheers Farina.

Hi Farina, it sounds like it could be blossom end rot which is caused by a lack of calcium and magnesium, applications of lime and epsom salts will help fix this, but inconsistent watering in summer, where the plant has dried out and then been watered can also lead to blossom end rot. Blossom end rot usually shows up with a brown blemish on the bottom of the fruit, make sure your tomatoes are regularly watered, deep watering is better than a light sprinkle. Alternatively, it could be a fruit worm, even though you say the fruit is unblemished, have a very close look for a pin prick size hole in the fruit. Or, when the fruit is cut open there will be tiny worms inside - about the size of a grain of rice. There isn't much that can be done if it is a fruit worm as it is inside the fruit and on the outside for such as short time, remove the infected fruit and disposing of in the rubbish bin to stop the insect overwintering in the soil.