Growing a great tomato garden is simple if you follow a few simple rules. You understand when you bite into a juicy tomato that it is largely water. Over 95% actually, and this means you can’t allow this plant to get too dry. As soon as it is too dry, it will get a condition called Blossom End Rot where the end of the tomato goes black, shrinks up and looks like a fungus has hit it. It’s a water-related problem.
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This is also a temperature problem; when the spring temperatures are too cold for the pollen and the fruit isn’t properly pollinated, the fruit will abort. This is one reason we plant tomatoes when the ground is warm and there is absolutely no danger of frost or cold summer nights.