Q.Tomatoes dieing off early
I have 3 varieties all from seed, some in growbags in the greenhouse, some in pots outside, some directly in the ground outside. They have all stopped growing at two trusses, and the flowers have not opened and are dying, as are some of the plants. The ones in the greenhouse are the worst. They have been watered regularly.
In the greenhouse what are the temperatures. Though Tomatoes need warm weather, if the temperature is too hot, they plants will suffer.
Check that the soil is well draining. These links will help you pinpoint the issue.
https://www.gardeningknowhow.com/edible/vegetables/tomato/tips-for-growing-tomatoes.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-blossoms-no-tomatoes.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-plant-problems.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-pots-containers.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-temp-for-tomatoes.htm