When Should You Fertilize Your Tomato Plants?

Tomatoes are a favorite among gardeners for their versatility and ease of growing. A well-cared-for tomato plant will produce healthy, juicy fruit all season long. One important aspect of caring for your tomato plants is fertilizing them, but when should you fertilize them? Let’s take a closer look at the best times to feed those tomato plants.

Before Planting

Although the best time to fertilize tomatoes comes after planting, giving them a boost beforehand doesn’t hurt. Tomatoes require nutrients like nitrogen, phosphorus, and potassium to thrive. A week before planting your tomato seedlings, work a balanced fertilizer into the soil. Look for a fertilizer with numbers on the label indicating an equal amount of nitrogen, phosphorus, and potassium, such as a 10-10-10 blend.

At Planting Time

When it’s time to plant your tomato seedlings, mix a slow-release fertilizer into the soil at the bottom of each planting hole. The slow-release formula will provide your tomato plants with nutrients over a longer period of time. Choose a fertilizer that contains calcium to help prevent blossom end rot, a common tomato disease. The ideal time to plant tomatoes is when the soil has warmed to at least 60°F (15.5°C) and all chance of frost has passed.

Throughout the Growing Season

Tomato plants require regular feeding throughout the growing season. As soon as the first tomato blossoms appear, it’s time to start fertilizing. Use an all-purpose fertilizer with higher potassium (K) content, such as a 5-10-10 or a 10-20-20 blend. Apply the fertilizer according to the manufacturer’s instructions, usually every two weeks. Be careful not to over-fertilize, as this can lead to excessive leaf growth and reduced fruit production.

Additional Tips

Tomato plants will also benefit from organic fertilizers like compost and manure. These natural materials help build soil structure, promote healthy microbes, and enhance nutrient absorption. Incorporate 1-2 inches (2.5-5 cm) of compost or aged manure into the soil around the plants every few weeks. Remember to water the soil thoroughly after fertilizing to help the nutrients penetrate to the root zone.

Finally, keep in mind that fertilizing tomato plants too late in the season can interfere with ripening. Avoid fertilizing your plants within four to six weeks of the first average frost date in your area. This will allow the fruit to mature naturally and develop their full flavor.

Conclusion

Fertilizing your tomato plants at the right time is essential for healthy growth and abundant fruit. Providing a balanced fertilizer before planting, adding calcium at planting time, and using a high-potassium fertilizer throughout the growing season are all important steps. Remember to supplement with organic fertilizers, water the soil after applying fertilizer, and avoid feeding too late in the season. By following these tips, you’ll be well on your way to growing the tastiest tomatoes of the season.