Q.what would cause no tomatoes on my plants
My plants are big and green, lots of flowers, but no tomatoes!

Certified GKH Gardening Expert
There are several reasons why you may fail to get fruits. Most common would be too much nitrogen fertilizer, which can be offset with the addition of phosphorus rich fertilizer or bone meal. You may also have an issue with poor pollination, which you can remedy by hand pollinating. The following articles wil provide additional information that should help: https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossoms-no-tomatoes.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/pollinate-tomatoes.htm