7 Best Fertilizers For Watermelon 2022 [Application Guide]

When your tender watermelon plants are looking healthy it doesn’t always mean they will bear plenty of fruit. Because as the plant grows vigorously it needs more and more nutrients from the soil to support the flowers and fruits in them. And this is why you shouldn’t sit back and watch. Rather you should give them proper care and healthy feeding.

Here, it is crucial that you apply the correct fertilizer in the right way since watermelons are pretty delicate. But the thing is, so many fertilizers are available in the market that we become easily confused about choosing the correct one.

Say no more! Because we have picked the 7 best fertilizers for your watermelon. In this article, you will find the features of every product and the method of application. So that you can make a well-thought decision about which fertilizer to choose for your garden on your own.

So, let’s get started already-

Top 7 Fertilizer for Watermelons – Comparisons

FertilizerNPKTypeForm Price
Miracle-Gro Plant Food24-8-16InorganicWater-soluble granule 
Dr. Earth Fertilizer4-6-3OrganicWater-soluble granule 
Down to Earth Fertilizer4-4-4OrganicWater-soluble granule 
Tomato-tone Fertilizer3-4-6OrganicWater-soluble granule 
Jobe's Plant Food2-3-5OrganicWater-soluble granule 
Miracle-Gro Plant Food18-18-21Inorganic Water-soluble granule 
Osmocote Plant Food14-14-14Inorganic Resin Coated Granule 

Top 7 Fertilizer for Watermelons

1. Miracle-Gro Water Soluble All Purpose Plant Food

Miracle-Gro Water Soluble All Purpose Plant Food

If you want to feed your watermelons an instant feeding then this Miracle-Gro Water Soluble All Purpose Plant Food will come in very handy. Because it quickly dissolves in water and reaches the plant root within a short time.

This product has an N-P-K ratio of 24-8-16 and a bounty full of other nutrients including all the necessary micronutrients like manganese, chelated iron, molybdenum, and zinc.

Moreover, it supplies phosphorus and potassium in readily available form. So it feeds the plant instantly and improves the watermelon’s quality and size within a few weeks. As a result, you get healthier and bigger watermelons fresh from your garden throughout the whole season.

One of its best features is, it is completely safe for all plants and doesn’t even burn the leaves when you use the product as instructed. Apply this water-soluble fertilizer every one or two weeks on the base of your watermelon plants during the whole growth period.

Besides this product is very versatile so you can use it on any kind of plant including all vegetable plants, flowering plants, indoor plants, trees, and shrubs. Here is how you can feed them-

  • Take a gallon of water and half a tablespoon of fertilizer.
  • Mix it properly with water.
  • Pour into a watering can and feed your watermelons at the base and soak the soil nicely.


2. Dr. Earth Organic Tomato, Vegetable & Herb Fertilizer

Dr. Earth Organic Tomato, Vegetable & Herb Fertilizer

Dr. Earth organic fertilizer is a premium quality choice for vegetables and fruits. Because it is made with 100% natural elements. Additionally, it contains TruBiotic technology. That means it has microbial organisms that make your watermelon plant drought tolerant.

Also, it contains seven probiotics that give your plant extra nutrition. And it helps to release a part of the nutrients in the soil quickly. And it releases the rest of the portion slowly so that your plant doesn’t run out of food for months. As a result, you get tasty, nutritious, and healthy fruits without even needing any chemical fertilizers.

It contains 4-6-3 NPK ratio which is basically derived from all organic sources like alfalfa meal, kelp meal, fishbone meal, fish meal, potassium sulfate, etc. Moreover, it’s completely free from any synthetic material, chicken manure, and any toxic ingredients. These features make it highly environment friendly.

For incorporating in the soil –

Mix ¼ cup of this product with 5 gallons of soil and then mix thoroughly. Add sufficient amounts of water to help it mix with the soil and activate the fertilizer.

To feed your watermelon plants–

Apply one cup per square foot of area every two months. You can also use it as a foliar spray occasionally on your plants to give them a boost of nutrients before flowering. In this case, mix one cup in one gallon of water.


3. Down to Earth Organic Vegetable Garden Fertilizer

Down to Earth Organic Vegetable Garden FertilizerDown To Earth has been one of the leading organic fertilizer brands since the 1980’s. They make premium quality fertilizer with the highest quality raw ingredients. So this one is an excellent alternative choice for your watermelons and any other fruits and veggie plants instead of other harmful chemical fertilizers.

The best thing about this fertilizer is they are made from the best quality organic nutrients in ideal amounts. Moreover, this fertilizer doesn’t contain any low-quality poultry or other wastes. So you can use this one without any hesitation for your watermelons and see it grow into the best quality one.

And there is more. This organic fertilizer has multi-purpose use. You can use this for amending your garden soil too. Apply the fertilizer for any kind of flowering and vegetable plants and herbs.

It contains 4-4-4 ratio of NPK, 1% water-soluble magnesium, and 0.4% iron. These ingredients are very effective in producing good-quality watermelons.

To apply this fertilizer on your watermelons–

Mix 2 tablespoons in a gallon of soil in a container for preparing the garden. And for garden soil put 2.5 kg (6lbs) for every 100 feet and mix thoroughly with the soil.

And to feed the plant use 50-100 grams of water and spray it on the watermelon’s roots every month during the growing season.


4. Tomato-tone Organic Fertilizer

Espoma Organic Tomato-tone

Espoma tomato tone organic fertilizer has been a leading organic fertilizer since 1929. For complete balanced nutrition, this organic fertilizer is a top-notch choice. It’s excellent for growing watermelon as well as tomato, brinjal, squash, and pepper plants.

You see, watermelons bloom in abundance. But sometimes the blossoms start to root. The good thing is this tomato tone organic fertilizer contains 8% calcium which prevents the blossoms from rotting. Moreover, it has 6% potash that helps to produce more flowers. As a result, you will get more watermelons.

The best feature of this product is, it has all the 15 essential nutrients in a balanced amount. And this tomato tone won’t even burn your plant leaves.

Besides, it contains beneficial microbes to help improve the soil and it doesn’t contain any toxic ingredients. Since this one is a slow-release fertilizer, once you apply it you don’t have to fertilize your plant for a while.

To apply this fertilizer–

Mix one part of tomato tone fertilizer with 30 parts of soil of container-grown watermelons. Or you can dig up small holes near the plant and put a teaspoon of the fertilizer if you are growing it in the field.

Apply on your watermelon plants after 10-14 days of germination and when the plant is established apply every 15 days interval during May to August.


5. Jobe’s 09026NA Plant Food Vegetables & Tomato

Jobe's 09026NA Plant Food Vegetables & TomatoIf your garden soil is lacking nutrients continuously then this Jobe’s Organics Vegetable & Tomato Fertilizer is the one for you. It also increases nutrient uptake as well as improves the soil condition of your garden. And we aren’t finished here yet. This Jobe’s plant food reduces insect attack and disease occurrence in watermelon.

This fertilizer is specially formulated to help your watermelon grow more fruit. This one is a certified organic fertilizer that ensures no use of any synthetic product.

In addition, it acts very quickly in the soil and supplies essential nutrients. Because it contains some microorganisms that help to break down the ingredient very fast.

The N-P-K ratio is 2-3-5. This feature makes it a very suitable choice for using on the flowering and fruiting stage. Because the higher ratio of potassium helps to produce good quality fruits.

To use it on the soil–

Apply in the soil before planting. Use 300-350 grams every 10 square feet area. And after the watermelon plants have been established, use 1.5 cups of fertilizer per foot of plant spread.


6. Miracle-Gro 2000422 Plant Food

Miracle-Gro 2000422 Plant FoodThis one is another popular product of Miracle-Gro that is specially formulated for tomatoes and melons. It instantly supplies nutrients to the plant helping to grow bigger and tastier watermelons. And not only just for watermelons, but it is also amazing for other vegetable plants like tomato, squash, pepper, etc.

It has a slightly different NPK ratio than the previous product of Miracle-gro that we have reviewed. It contains 18% nitrogen, 18% phosphorus and 21% potassium. So the higher ratio of all the essential nutrients helps to stabilize watermelons even if they are weak. Additionally, it contains iron and water-soluble forms of magnesium and copper.

It’s an inorganic fertilizer that starts to work almost instantly without burning the watermelon leaves. Moreover, you can use this one in all kinds of veggies and herb plants without worrying about their safety.

To apply this fertilizer–

Mix a tablespoon of this fertilizer with a gallon of water and pour it evenly on the base of your watermelon plants with the help of a watering can. Repeat the same way every week.


7. Osmocote Smart-Release Plant Food Flower & Vegetable

Osmocote Smart-Release Plant Food Flower & Vegetable

Osmocote Smart-Release Plant Food Flower & Vegetable is specially made to help the development of the roots of your plant and result in a wonderful growth of them. This inorganic fertilizer is suitable for all kinds of vegetables including tomatoes, peppers, carrots, onions, bulbs, beans, and even for perennial shrubs and trees.

If you are very busy and hardly have time to engage in any garden activities every single week you can take full advantage of this product.

You must have noticed the word “smart release” in the name. This is because the nutrient granules are coated with semi-permeable resins. Because of these coatings, the nutrient release occurs during the active growing season of the plant when the soil temperature is warmer near the root zone. So there is no need to apply fertilizer every now and then.

So, once after applying it can feed your plants up to four months. This means you will get juicy and flavourful watermelons throughout the season. Moreover, it has a very balanced ratio of NPK in 14-14-14 form.

To apply this fertilizer–

Sprinkle one tablespoon of the granules in every 4 sq. ft area. After that use a spread and lightly mix the granules with the soil up to 3 inches deep. Then water the area lightly so the fertilizer can thoroughly mix with the soil. Reapply every 4 months.


How To Fertilize Watermelon Correctly

Fertilizing Watermelon Plants

  • It’s super easy. Start with tilling the soil of your garden thoroughly. Then if you are using organic fertilizer mix it with the soil.
  • Follow the label direction of your fertilizer package to know what amount to use. Because different kinds of fertilizer have different dosages.
  • But if you are using inorganic fertilizer then mix it with water as per the label instruction and pour it over the soil surface.
  • It’s better to wait for one or two days before planting.
  • Then plant the seeds of your watermelon in the soil.
  • After that, fertilize the watermelon plant every one or two weeks followed by watering. Because the water will help to mix the fertilizer with the soil more evenly.

Homemade Watermelon Fertilizer

Make Banana Peel Fertilizer for Watermelon plants


  • 8 banana peels
  • 8 tablespoons of Epsom salt
  • 6 eggshells
  • Water


  • Put all the items in the blender and grind into a paste.
  • Now take half a cup of water and mix with the paste.
  • Mix this liquid with the irrigation water and pour it on the base of the watermelons.

Frequently Asked Questions (FAQs)

1. What is the best kind of fertilizer for watermelon?

Watermelons require a fertilizer with a balanced dose of potassium and phosphorus for ideal melon production.

2. How do you increase watermelon fruit size?

Prune off the shriveled or bad fruits and just keep the good ones. This will help to shift all the energy and nutrients into healthy fruits. As a result, the healthy ones will quickly grow larger and bigger.

3. Is urea fertilizer good for watermelon?

Watermelon needs a good load of urea during the onset of growing as it contains nitrogen. Because urea helps the plant to get a good vigor and gives better support to the watermelons in the growing season.

4. How much water does a watermelon need?

Watermelons require plenty of water for their growth and development. Water them up to 1 or 2 inches of soil depth every week. Keep the soil moist during the fruiting and ripening stage.


There is no alternative to using fertilizers if you want your watermelon plant to grow and thrive. Because if you provide the ideal conditions, it will reward you with plenty of juicy and mouth-watering watermelons.

Now that we are almost at the end of our article, I hope you have a complete understanding of the top 7 fertilizers that work best for the watermelons. Each item has different kinds of advantages of its own with different kinds of growing conditions.

So, I hope all the information I put in helped you to decide what works the best on your watermelon plants.

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