When a plant produces fruits as delicious and juicy as tomatoes, you know it needed a ton of nutrients to support it along the way. The right organic fertilizer can supply all those needed nutrients, fuel your tomato’s growth, and even increase your harvest throughout the season.

Before we get into the best liquid fertilizer for tomatoes options, let me say one thing: Start with good soil.

Tomatoes love growing in soil that’s not just rich in organic matter, but that also provides the roots some structure and good drainage. Tomatoes will need lots of nutrients to form flowers and then ripen fruit. And they’ll also need to feel like their roots are nice supported when they’re bearing all that heavy fruit. (Learn more about the best soil for vegetable gardens.)

best liquid fertilizer to maximize your tomato harvests. tomato plants with large and small tomatoes.

This post contains affiliate links, which means I earn a small profit when you click on the link and purchase my recommendations. As an Amazon Associate I earn from qualifying purchases. Thanks for supporting my small business! 

WHY USE A LIQUID FERTILIZER?

Liquid fertilizers can be easily applied to the soil by watering around your tomato plants’ roots. This provides quick nutrient absorption, which is particularly beneficial during periods of rapid growth or fruit production. When you’re shopping for a liquid fertilize, look for a water-soluble fertilizer. Make sure to follow the manufacturer’s instructions for the correct application rates.

Photo of roma tomatoes. Best Liquid Fertilizer for Tomatoes - Why Use a Liquid Fertilizer

THE BEST LIQUID FERTILIZERS FOR TOMATO PLANTS

When it comes to nourishing your organic tomato plants—or any edible plant—I recommend sticking with organic fertilizers. These products are derived from natural ingredients and offer a healthier, more sustainable way for fertilizing tomatoes. All that to say, you’ll feel really good about each tomato you pop into your mouth straight from the vine.

Here are the some of the best products to help your tomatoes thrive in your garden:

MicroLife’s Maximum Blooms 

Don’t let the word blooms fool you into thinking this fertilizer is only for flowers. Every single tomato, after all, comes from a flower. I actually use MicroLife’s Maximum Blooms for all my fruiting plants.

This organic liquid fertilizer provides over 100 vitamins and minerals, including those that encourage flowers, but you don’t have to worry about it burning your plants.

You have two application options: mix it up in a watering can before watering around the base of the plant, or dilute it, pour it into a spray bottle, and use it as a foliar spray on the leaves.

Compost Tea

Compost tea is a type of fertilizer you can brew at home. Make your own compost tea by steeping organic compost in water for about 24 hours. The result will be a nutrient-rich liquid that can be applied directly to the soil, providing a quick boost of nutrients and beneficial microorganisms.

Arber’s Organic Plant Food

I love Arber’s line of certified organic concentrates for the garden. Their plant food has all the necessary nutrients for healthy plants in your vegetable garden, and what’s really cool is it’s made from recycled grocery store food waste.

It can encourage your tomato plants to produce thicker leaves, more blooms, and deeper roots to support the weight of all that heavy fruit. It even gives your plants a little immunity boost to help them fight off pests and various disease.

All you have to do is mix 4 ounces into 1 gallon of water and apply every 2 weeks. You can also use this product as a foliar spray.

 

OTHER TOMATO FERTILIZER OPTIONS

Don’t feel limited to liquid fertilizers. I use a combination of liquid and the other types of fertilizers mentioned below in my own garden. The key is just to avoid over-fertilizing. I’ll talk about timing your fertilizer applications in a bit.

Organic Compost

Tomatoes love compost, which is basically just broken-down organic materials. Compost is rich in essential nutrients that spur healthy growth. Even better, it acts as a slow-release organic fertilizer, so you can apply compost around the base of your tomato plants as often as every week without running the risk of burning, or overstimulating, your plants.

Compost is just good for your overall garden health because it improves the soil structure and fertility over time. It even helps retain soil moisture in the hot summer months.

Give your tomatoes a good start by adding some compost to the garden when you’re planting tomato seedlings. Every couple of weeks, you can push fresh compost around the base of your plants to give them more support as they grow (this is called hilling).

Worm Castings

Worm castings (vermicompost) is a natural source of vitamins and nutrients produced by our little earthworm friends. In other words, it’s worm poop. Like compost, worm castings can enhance soil fertility, improve water retention, and provide much-needed essential nutrients for tomatoes and all your other fruits and veggies.

Granular Fertilizer

Granules make for great slow-release organic fertilizers. They provide a steady supply of nutrients over a long period of time, without the risk of overfeeding or creating nutrient imbalances.

Look for granular fertilizers with a balanced NPK ratio. I’ve had great results with MicroLife’s Ultimate Organic Granular Fertilizer.

 

 

STEPS TO FERTILIZE TOMATOES

Tomatoes are heavy feeders, so they need a steady diet of nutrients to produce high yields of fruit. But the key nutrients they need changes slightly as they grow. For best results, you’ll fertilize your plants in 2 stages.

First stage: young plants

Don’t forget to add a 2- to 3-inch layer of compost to the top of your bed before planting your seedlings.

In these early days, our focus is to encourage the tomato plants to grow strong roots and stems. I like to add an all purpose organic fertilizer such as MicroLife Ultimate Organic Fertilizer to accomplish this.

All purpose fertilizers provide a well-balanced blend of essential nutrients, including nitrogen (N), phosphorus (P), and potassium (K). Nitrogen supports vigorous leaf growth, phosphorus promotes root development and flowering, and potassium enhances overall plant health and disease resistance.

 

young tomato plant growing in a raised bed garden. best liquid fertilizer for tomatoes

Second stage: mature plants

As soon as you see the first flower forming on your tomato plant, it’s time to switch up your fertilizer routine. You now want to avoid adding too much nitrogen, which will encourage the plant to produce more green leaves instead of flowers and fruits.

Instead, you want to add a potassium- and phosphorus-rich fertilizer to encourage flowering. This is when I would add something like MicroLife Maximum Blooms to ensure higher yields of fruit.

Throughout the full growing season, you can, of course, continue to add compost to the base of your plants to make sure you’re supplying any additional nutrients tomatoes need.

 

tomato plant flowering. best liquid fertilizer for tomato plants.

THE BEST WAY TO APPLY FERTILIZER

No matter which type of tomato fertilizer you’re using, make sure to follow the label’s directions. Water around the base of your tomatoes thoroughly before applying any fertilizer to prevent root burn. Spread the fertilizer evenly around the base of the plant, avoiding direct contact with the stem.

Liquid fertilizer

For liquid fertilizers, follow the package instructions for the recommended dilution ratio and apply directly to the soil. You can also follow the package instructions to make a foliar spray for the leaves of the plant for a fast nutritional boost. For example, I fill my 2 gallon watering can with water and 1/2 cup of Maximum Blooms to water in at the base of my tomato plants. 

Granular fertilizer

Lightly scratch the surface of the soil with a hand rake to incorporate the granules and water gently after application. 

 

watering in maximum blooms liquid fertilizer to tomato plants.

ADDITIONAL TIPS TO GROW HEALTHY TOMATOES

Here are some easy things to keep in mind to maintain overall plant health and maximize fruit production:

Prioritize Good Drainage

Make sure that your tomato plants have good drainage. If you’re growing in a container or pot, there should be at least one good drainage hole at the bottom to allow water to escape. Use a drill to add one if needed. Tomatoes really don’t like their roots sitting in water for too long.

Give Your Tomato Plants Lots of Sun

Tomatoes need at least 6 hours of sun but will be much more productive with 8 hours a day. That being said, they can burn in afternoon sun, so try to get them more morning sunlight. If you notice your leaves are getting scorched by late afternoon sun, cover them with a shade cloth to filter some of the light.

Water Consistently

Your plants need deep, consistent watering to produce juicy tomatoes. Fluctuations in watering can cause the fruit to split or not properly form, so water your tomatoes regularly.

Tomatoes can suffer from diseases that are splashed up from the soil, so watering with drip lines or gently at the base with a wand is important to prevent these diseases. Learn more about watering your tomato plants here.

Prune Regularly

Remove discolored or damaged leaves each week. Learn more about pruning tomatoes here.

 

pruning tomato plants to keep them healthy. best liquid fertilizer for tomato plants

ENJOY GROWING TOMATOES!

 

I hope these fertilizing tomato tips help you grow the most flavorful tomatoes you’ve ever tasted.