Skip to Content

Fertilizing Tomato Plants – How To Give Your Tomatoes Perfect Power!

When it comes to fertilizing your tomato plants with the perfect dose of power and energy, you might just be surprised at what works best to produce incredibly healthy plants and a big harvest!

Tomatoes are one of the heaviest feeders of all vegetable plants in the garden. Unfortunately, no matter how rich and fertile your soil might be at planting time, there simply are not enough nutrients available long-term to power maximum growth and production.

Along with the “BIG 3” of nitrogen, phosphorous and potassium, tomato plants need plenty of calcium, magnesium and a host of other micro nutrients to thrive and produce. And the only way to give them all of those nutrients once they are growing is a with a little boost of fertilizer.

fertilizing tomato plants
Giving your tomato plants the power they need in a form that is easy to absorb can help them develop strong, healthy stems and foliage – and lots of tomatoes!

But – and this is key – what you boost them with, how much you give them, and how you apply are all critical in just how successful your tomato plants will be.

If you don’t give your plants enough of the right nutrients, they will struggle to grow and produce. On the other hand, give them too much power or too much of the wrong power all at once, and it can create massive plants that look ultra-healthy – but that produce small yields or even no tomatoes at all!

Here is the good news – it’s not difficult to fertilize tomatoes. Nor is it hard to give them exactly what they need for optimum growth. With that in mind, here’s an in-depth look at how to provide your plants with the perfect dose of power!

Fertilizing Tomato Plants For Success

Using The Right Nutrients For Growing – And For Blooms!

One of the biggest mistakes gardeners often make when fertilizing tomato plants is giving them too much nitrogen. Yes, nitrogen is important. It is vital for helping grow thick stems and foliage. And that in turn helps the plant gain more energy through photosynthesis.

But too much nitrogen is a bad thing for tomato plants. Yes, it gets them deep green and healthy looking. And yes, it grows them big. But when a tomato plant gets excess nitrogen, it uses it to only grow big. And at the expense of setting blooms and producing tomatoes!

tomato nutrients in the soil
No matter how rich your soil is at planting time, your tomato plants will eventually use up in the nutrients in it. But with a little bit of fertilizer, you can keep giving your plants the energy they need deep into the season.

That is exactly why when selecting a fertilizer, make sure at the least it has a good balance when it comes to its N-P-K ratio, and especially not higher in Nitrogen. In fact, it’s actually even better to have a higher phosphorous number. Why? Because phosphorous powers blooms – and blooms create future fruit! Nitrogen, on the other hand, just grows the plant bigger.

We will cover more on specific fertilizer choices in a bit, but for now, it’s important to first cover the best method for delivering fertilizer to your plants. And for us, the only way to go is with liquid fertilizer!

Why Liquid Fertilizers Work Best – Fertilizing Tomato Plants With Perfect Power

For going on ten years now, we have used a very simple method for fertilizing our tomato plants. And it works equally well whether growing tomatoes in our main garden, or in our buckets and containers.

There are certainly a lot of choices for fertilizing tomatoes. In fact, from granular mixes, to powders, liquid concentrates and more, the selection can mind-boggling! But for us, especially when it comes to fertilizing tomatoes and other vegetable plants, liquid fertilizers are the ideal solution.

We have always been partial to liquid fertilizers for a few very important reasons. For one, nearly all liquid fertilizers can be absorbed in two ways, through the roots and through the foliage. And that double dose of goodness means plants get the energy they need fast.

For Even More Fertilizing Tips, Listen To Our How To Fertilize Tomatoes Podcast Below!

Even better, however, is that they can be applied as part of your watering routine, giving the plants moisture and nutrients all at the same time. Here is a look at how we fertilize our plants, along with what we like to use and the timing and strength of each dosage.

Selecting The Best Liquid Fertilizer

There are some great all-natural liquid fertilizer options on the market. Some, like Espoma Tomato Liquid Plant Food, are even created with powering tomatoes in mind. With a 1-3-1 N-P-K ratio, it gives a higher dose of phosphorous for more blooms, but at a slower, steady pace that won’t overpower your tomato plants.

For us, our liquid fertilizer of choice is and will always be compost tea. Not only is it 100 percent natural and organic, it’s easy to make and apply. In addition, if you have your own compost on hand, it’s completely free to make! See: How To Make Compost Tea With Ease

Compost tea also happens to be teeming with the perfect blend of nutrients that help tomato plants thrive. Nutrients that absorb easily, and help to power a crop to a harvest that vegetable gardening dreams are made of!

But one thing is for sure, whether using a commercial liquid fertilizer or compost tea – fertilizing with a liquid approach is the answer. All that is left for big success is knowing when to fertilize your tomato plants – how much to use – and for how long to apply it.

When To Fertilize – How To Fertilize Tomato Plants Right!

Along with using the right fertilizer, knowing when to apply it and at what strength are the two final keys to growing a bumper crop of tomatoes. It is better to provide your plants with regular but light dose than just a few large applications of fertilizers.

Espoma Fertilizer
With a 1-3-1 N-P-K ratio, Espoma’s organic tomato boost s perfect for powering plants low and slow.

Remember that steady growth is great growth and allows for more blooms and production. That is one of the reasons we love compost tea for tomatoes. There is little worry of overpowering plants with compost tea. It is so balanced and natural we can use it at full strength every ten to fourteen days without worry.

The same goes for liquid fertilizers with low N-P-K ratios like the Espoma Tomato Boost. If your are using commercial liquid fertilizers with higher ratios, simply mix at half or one-third of the recommended strength before applying.

The lower dosage will keep plants from growing too rapidly. But, by applying every ten to fourteen days, it also keeps a steady supply of nutrients coming to the plants. Both of which are absolutely critical for growing tomato plants that produce!

One Final Secret Tomato Fertilizing Trick – The Worm Casting Boost!

We do add one final secret weapon to our fertilizing routine – and that is a monthly addition of 1/2 cup of worm castings spread around the soil at the base of each plant. By doing this, every time we water or it rains, the power of the castings soak down into the roots of the tomato plant.

Worm castings are another perfect, low and slow source of power. They will not overpower plants, but do they every make a difference in keeping your tomato plants strong and productive. The monthly castings dose is the final amazing push of nutrients to our plants – and it works like magic! Affiliate Product Link : 100% Pure Worm Castings

How Long To Fertilize? – The Secrets To Fertilizing Tomato Plants

It is important to allow your plants to establish in the soil a bit before fertilizing. For transplants, that means allowing them to adjust for about 10 days in the soil after planting day. If you happen to grow your plants directly from seed, allow the plants to grow at least 4 to 6 inches high above the ground before starting to fertilize.

big harvest
More phosphorous helps with more blooms. And more blooms means more tomatoes!

Once established, plants should be fertilized every 10 to 14 days for the first 10 to 12 weeks. When using a liquid fertilizer, it is best to do so in the morning hours. This will keep the sun’s rays from burning any wet foliage.

We use about one-eighth of a gallon per plant for small transplants at first. As they continue to grow and develop, we increase the amount per plant to one-quarter to one-half of a gallon for each tomato plant. To apply, use one-third of each dose to water foliage, and the remainder around the root zone of each plant.

Again, the beauty of liquid fertilizing is the plant absorbs both through its roots and through its leaves.

When To Stop Fertilizing

Once plants reach the point where they fruit heavily and the first crop starts to ripen, we stop fertilizing. We do this to allow the plant to concentrate its energy on fruiting and ripening. We do continue to use castings every month as it helps provide a boost even while they produce.

Unfortunately, fertilizing plants with liquid power later in the year will cause them to use the excess energy to grow more foliage, and not produce more flowers. All in all, our plants receive a total of five to seven doses of liquid fertilizer.

It has certainly been a formula that has worked like a charm. Here is to powering your tomato plants to an incredible harvest this year by fertilizing them for success! Happy Gardening – Jim and Mary.

Jim and Mary Competti have been writing gardening, DIY and recipe articles and books for over 15 years from their 46 acre Ohio farm. The two are frequent speakers on all things gardening and love to travel in their spare time.

As always, feel free to email us at with comments, questions, or to simply say hello! You can sign up for our free email list in the subscribe now box in the middle of this article. Follow us on Facebook here : OWG Facebook. This article may contain affiliate links.