Overgrown Tomato Plants Without Flowers

Tomatoes have no flowers but lots of leaves. 

Question: My tomatoes are growing lots of leaves but have no flowers or fruit. What is the problem? What do I do? 

Answer: Tomatoes that grow many leaves but produce few or no flowers are usually getting too much nitrogen, too little sunlight, excessive heat, or too much water.

Here is what to do now:

1. Stop fertilizing with high-nitrogen fertilizer. Avoid lawn fertilizer, manure, or products with a high first number, such as 20-10-10. Use a tomato fertilizer with less nitrogen and more phosphorus and potassium, such as 3-5-6, 4-6-8, or 5-10-10.
2. Give them maximum sunlight. Tomatoes need at least 6–8 hours of direct sun, preferably eight or more.
3. Water deeply, but less often. Let the top inch or two of soil begin to dry before watering again. Constantly wet soil encourages leafy growth.
4. Do not heavily prune them. Remove only yellow leaves, leaves touching the soil, and a few overcrowded shoots. Cutting back the main stems can delay flowering further.
5. Check the temperature. Tomato flowers may not form—or may drop—when daytime temperatures regularly exceed about 90°F or nights remain above 70–75°F. During very hot weather, provide light afternoon shade and keep the roots evenly moist.
6. Be patient after changing care. Once excess nitrogen or heat stress improves, flower clusters may begin appearing within roughly one to three weeks.

If the plants are extremely tall and sprawling, gently tie them to stronger supports rather than cutting them back severely.