Best Fertilizer Formula for Tomato Plants: High Phosphorus and Potassium

Tomatoes need modest nitrogen but abundant phosphorus and potassium for fruit development.

Ideal Ratios

• Top choice: 5-10-10
• Good alternatives: 9-12-12, 10-10-10

Why Low Nitrogen?

Excess nitrogen → tall, lush plants with few/small fruits. Phosphorus (root/bloom) and potassium (fruit quality/disease resistance) drive production.

Application

Apply at planting and side-dress when fruits set. Follow label rates—more isn't better.