How to Fertilize Tomatoes in June for an Even Bigger Harvest – and the 1 Feeding Mistake That Can Hurt Your Plants

June is here and that means for most gardeners across the US, it’s time to transplant your tomatoes. Transplanting time is also the perfect moment to give your tomatoes a boost with their first dose of fertilizer for the season.

Maybe you live somewhere warm and you’ve already put your tomatoes in the ground or you live in the far north and you’re still waiting for that final frost date. Either way, whether you’ve already moved your plants into the garden or that’s on your to-do list for this weekend, now is the ideal time to fertilize tomatoes.

But before you start feeding your favorite vegetable, it’s important to understand exactly what kind of fertilizer your tomatoes need at this stage in their lifecycle. It’s also vital to apply fertilizer in the right way to ensure your plants get the biggest benefit and you don’t accidentally set back their growth.

I’ll walk you through how to fertilize tomatoes in June for a huge harvest this summer. Plus, I’ll reveal the biggest tomato feeding mistake that can potentially ruin your plants for the rest of the season.

Do You Have to Fertilize Tomatoes in June?

June is a great time to start fertilizing tomatoes. Most gardeners begin transplanting tomatoes outdoors between mid-May and mid-June. The exact date varies depending on your growing zone and last frost date in spring.

But by mid to late June, almost everywhere in the contiguous US should be free of frost, which means it’s safe to plant your tomatoes outdoors. When you transplant your tomatoes outdoors, you should also give them their first dose of fertilizer.

Benefits of Fertilizing Tomatoes in June

Fertilizing tomatoes in June at the time of transplanting or just after planting tomatoes outdoors gives them a head start that will benefit them for the rest of the summer. It helps them establish a healthy root system that will set them up for strong growth the rest of the summer. Fertilizing in June also provides them with a much-needed boost of nutrients that will help them transition from indoor growing to thriving outdoors in the garden.

If you started tomatoes from seed, by June, your seedlings have likely depleted all the nutrients that were stored in the original seed. Most seed starting mixes don’t include much fertilizer – if any at all – so by the time your seedlings are big enough to transplant, they are in need of more nutrients.

Fertilizing tomatoes in June, just after planting, replenishes your plants with necessary nitrogen, phosphorus, potassium, and other micronutrients they need to thrive. If your tomato seedlings are turning yellow, that’s a clear sign that they need a dose of fertilizer when you transplant them.

How to Fertilize Tomatoes in June

The easiest way to fertilize tomatoes in June is when you transplant them into the garden. There are two ways you can do this. The first way is to amend the soil in each individual hole. After you dig the hole for each tomato plant, add a dose of a slow-release organic fertilizer. My favorite tomato fertilizer is this one from Jobe’s on Amazon. Follow the instructions on the package for the proper dosage. Then mix the fertilizer into the surrounding soil and plant your tomato.

The other way to fertilize tomatoes at planting is to amend the soil in the entire area where you plan on putting your tomatoes. Again, use an organic slow-release granular fertilizer that will gently feed your plants all season. Follow the recommended dosage on the package for the size area you need to cover. Then use a rake or one of my favorite gardening tools, the Garden Weasel from Amazon, to incorporate the fertilizer into the soil and plant.

Water plants after you finish transplanting your tomatoes to help spread the nutrients to your tomatoes’ roots. Always water plants after fertilizing and transplanting to help them settle into the soil and prevent transplant shock.

If you’ve already transplanted your tomatoes into the garden and forgot to fertilize, don’t worry – it’s not too late. You can apply a side dressing of an organic granular fertilizer to your plants now to give them a boost. Simply sprinkle the recommended amount around each plant and gently use your fingers to mix it into the soil. Don’t get too aggressive with this or you could damage some of the roots. Next, water in the fertilizer to help it seep down into the roots.

Alternatively, you can use a liquid tomato fertilizer like this organic option from Espoma. Mix the recommended dosage for your number of plants into a watering can and drench your plants at the soil line. After the first dose of fertilizer for the season, keep reapplying your organic fertilizer of choice every two to four weeks or follow the directions for the specific plant food you use.

Don’t Make This Feeding Mistake

Feeding tomatoes in June can give them a huge boost that will serve them well during the peak of the summer growing season, but there’s a common fertilizing mistake that can actually set back plants. You should never fertilize plants during the heat of the day.

Fertilizing tomatoes in the middle of a hot June afternoon is a recipe for disaster. It can cause fertilizer burn on plants and scorch the foliage they need to capture the sun for photosynthesis to grow. Young plants, especially newly transplanted ones, are most at risk of fertilizer burn and leaf scorch.

The best time to fertilize plants is in the morning. This allows time for any excess water that may get on foliage to dry before the end of the day. That’s important because wet leaves invite many common tomato diseases. So give your plants a dose of fertilizer in the morning some day this month for an even bigger harvest of tasty tomatoes later on in the summer.

Tomato Fertilizing Essentials