Some of the blossoms on my tomato plants are disappearing. The plants are too tall to be affected by rodents and there are no signs of insects. Could the blossoms just be dropping off? Any ideas or recommendations?
Your observations and process of elimination are very good. Tomato blossoms can fall off prematurely when it is very cool or very hot, or the soil is dry. Michigan’s summer so far has been unseasonably cool, but with plenty of moisture.
Your solution is to improve growing conditions by “turning up the heat.” When temperatures continue to be cool, mulch with black plastic to warm up the soil. You can pair that with wrapping clear plastic on stakes around the plant to form a mini-greenhouse. Keep water consistent, watering when the soil is dry 1 to 2 inches beneath the surface.