By Haueter
United States 
None of my 50 tomato plants has developed a single fruit. I planted 50 seeds, half Burpee Marglobe Heirlooms and half Burpee Big Boy hybrids. The plants are growing well, have bloomed, but none have developed fruit. I planted seeds about 1 April. I have 20 plants in the ground and 15 plants in pots. What's going on? I've successfully grown tomatos in MN and AZ and a few in MT in previous years, but have never had a 100% frailure, such as this year.
15 Jul, 2012
Answers
Have you had flowers?
If you have try misting them regularly if the atmosphere is very dry and tap the plants lightly to disturb the pollen
You could add a weak high potash feed when you water just in case
15 Jul, 2012
Often, gently tapping the flowers in the morning will set plenty of fruit, if the bees aren't doing it for you. If you are in a part of the U.S. that is getting 105ยบ plus weather lately, your tomato pollen may have died, so you will have to use a tomato setting spray to get fruit.
16 Jul, 2012
Previous question
Are there insects around to pollenate the flowers?
15 Jul, 2012