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Why are some of my tomatoes rotten on the bottom? And when do they stop setting fruit?

That's blossom end rot. It occurs when water fluctuations in the plant prevent calcium from reaching the tip of the tomato. The cells die and start to rot. It's usually the first tomatoes that are affected. We can avoid this by using calcium sprays. It seems strange in our calcereous soils that we should need calcium, but it's the water fluctuations that prevent the calcium from reaching the fruit. So, the sprays can help early in the season.

Try to keep the soil moisture as moderate as you can; don't let it get extremely wet or extremely dry. Of course, you can't control the seasonal gullywashers!

The best news is that as the season goes on, the tomatoes are usually fine. Sometimes it's the variety, as well, so note which varieties are most problematic for you.

When the weather gets hot, tomatoes don't set fruit. We're really kind of a spring and fall tomato season, which is why we encourage you to get your tomatoes early and pot them up until the freeze weather passes.

If you want some tomatoes through the heat, choose the smaller variety types, like cherry tomatoes.

Finally, look out for pests and diseases. Keep the soil mulched to help prevent leaf diseases from the soil splashing up. Even then, you may get some fungal disease. Again, not the variety, since some are more susceptible than others.

You can also spray with fungicides to help the problem, but avoid application in the heat of day.

What I usually like to do instead is just prune off the lower leaves that are starting to get leaf spots, and continue to fertilize and water. Keep an eye out for aphids and spider mites and control with some insecticidal soap.



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