Tomatoes should be fertilized regularly throughout their growing season, but the frequency depends on the growing conditions and type of fertilizer used:

• For in-ground tomatoes, fertilize once every 4 to 6 weeks during the growing season

• For tomatoes grown in containers, fertilize more often, about every 2 to 3 weeks, because container soil nutrients deplete faster

• Some gardeners prefer organic liquid fertilizers weekly for better success, especially during active growth and fruiting

• Slow-release pellet fertilizers may only need to be applied every 3 to 4 months, but supplementing with liquid feed weekly once fruit appears is common

• Fertilizing is recommended at key stages: before transplanting, at planting, before flowering, and when fruits are small. Different fertilizer formulations can be used at these stages to meet nutrient needs

• Liquid fertilizers are often applied weekly from flowering through fruiting to support healthy growth and abundant harvests

In summary, a general guideline is to fertilize in-ground tomatoes every 4 to 6 weeks, container tomatoes every 2 to 3 weeks, and use weekly liquid feeding once flowering and fruiting begin for best results. Adjust frequency based on fertilizer type (slow release vs. liquid) and plant growth stage.