A gardener troubleshoots a tomato plant that won't bloom by considering the current temperature, weather and pollinators and using the appropriate varieties of tomato plants. For example, tomato plants are very sensitive to temperature and some varieties live better in hot climates than others.
A tomato plant is very sensitive to temperature, refusing to bloom if it is either too hot or too cold. HGTV points out that temperatures over 85 degrees Fahrenheit can prevent some plants from flowering. The wrong humidity levels also affect specific species. The best way for a gardener to work around weather problems is to purchase a type of tomato plant best suited to the climate. Florasette, heat wave, solar set, sunchaser, sunmaster, supride and surfire are all varieties of tomato plants that thrive in hot and humid weather. Early girl, legend, matina, Oregon spring, polar baby and silvery fir tree are all colder weather varieties.
A lack of pollinators also prevents tomato plants from blooming and producing fruit. If there are not insects to spread the pollen around, a gardener has to do it by hand. In some cases, tomato plants are either not receiving enough water or insufficient magnesium. Tomatoes need to be watered deeply and regularly. If the plant has insufficient magnesium, the solution is to add seaweed extract to the soil or reduce the use of high nitrogen fertilizers.