Troubleshooting
Dark patches on the bottom of fruits are a nutritional disorder known as blossom end rot. This is best prevented by growing tomatoes in well-prepared soil with constant light moisture. Yellow leaves may indicate a lack of magnesium, so apply a liquid feed. In Australia fruit fly are a pest of tomatoes. Place any infested fruit, or fruits that have fallen to the ground, in a sealed plastic bag in the sun for at least 7 days to kill the eggs and larvae. Do not compost infested fruits as this will lead to the fruit flies completing their life cycle and the problem recurring.