When growing tomatoes, it helps to know the various temperature ranges for healthy plant growth.
If it is too cold, it may damage the tomato plant or its fruit.
If it is too hot, plant growth will slow down, and fruit will not set or form properly.
The illustration below (as a PDF) gives a good idea of the key temperature ranges for tomato plants. (To download the file, click the download button below!)
If cold weather is the problem, check out my article on protecting tomato plants from cold and frost. Enjoy!