5 Best Fertilizer for Watermelon: Ensure The Best


Although some may claim that their watermelon plants are thriving on their own, any veteran gardener will tell you that fertilizing them from time to time yields amazing results.

However, finding the Best Fertilizer for Watermelon isn’t as easy as it seems. To alleviate your worries, we’ve come to save the day. This article contains the top 5 fertilizers for watermelon on our list.

To take things up a notch, we’ve also included a buying guide to help you pick one. So without further ado, let’s hop right in. 

Photo of a watermelon plant
Photo by Tchara

Comparison Table

Miracle-Gro Plant Food Plus Calcium 3002610N-P-K Ratio : 10-5-15

Product Dimensions: 4.13 x 9.8 x 7.5 inches

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EcoScraps for Organic Gardening Plant Food
N-P-K Ratio: 5-4-6

Product Dimensions: 4 x 13.5 x 6 inches

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The Old Farmer’s Almanac Organic Plant Food Fertilizer
N-P-K Ratio: 8-4-8

Product Dimensions: 8 x 4 x 11.25 inches

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Burpee Organic Tomato and Vegetable Granular Plant Food
N-P-K Ratio : 3-6-4

Product Dimensions: 4 x 10.25 x 12.5 inches

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Dr. Earth Premium Gold Fertilizer 
N-P-K Ratio : 4-4-4

Product Dimensions: 2 x 13 x 20 inches

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1. Miracle-Gro Plant Food Plus Calcium 3002610

Product Overview

First off, we have the Miracle-Gro Continuous Release Plant food. Wondering how this is different from your ordinary fertilizer?

To begin with, it’s enriched with calcium that ensures you get stronger roots. Since root health is directly connected to your plant, you can be assured of getting strong and sturdy plant growth. Besides, calcium also encourages cell growth, preventing any plant disorders that stem from a calcium deficiency. 

Moreover, it doesn’t contain any harsh or harmful chemicals. Enriched with natural nutrients, this fertilizer directly enriches the soil and encourages healthy bacteria to flourish.

When you start applying this to your plants, you’ll notice that your plants are growing stronger, and yielding more fruits. 

Another feature that we really enjoyed was how easy this fertilizer is to use. All you need to do is shake the bottle and pour the granules directly on the plant. Next, water as usual and that’s all there is to it. 

You can use this on any fruits and vegetables, and the fertilizer will continuously feed your plant for up to 3 months!

If you’re wondering about the NPK ratio, this Miracle-Gro fertilizer comes with a 10-5-15 count. That means you’re getting 10% nitrogen, 5% phosphorus, and 15% potassium for your plants. 

The high percentage of potassium in this fertilizer helps the plant in absorbing water and also retaining nutrition from the soil. This helps your plants in growing stronger and taking up all of the soil’s goodness. 

2. EcoScraps for Organic Gardening Tomato & Vegetable Plant Food

Product Overview

Looking for an organic fertilizer that will also help you contribute to the climate? Then this fertilizer from EcoScarps has your name written all over it. 

According to a survey, Americans waste around 30 million tons of food every year! Although food waste is a spectacular fertilizer on its own, it has a nasty odour that may be unbearable. 

On the other hand, this product uses these food waste and recycles it. Next, these are converted into fertilizer so that you can use it on your watermelon plants. 

Fret not, there’s no manure or animal waste included, that could stink up your garden. All in all, you’re nourishing your plants but also saving the environment!

Moreover, this fertilizer is super easy to use too! Simply mix around 2 tablespoons of fertilizer with every gallon of potting soil and you should be good to go. 

Another benefit is that this fertilizer is super versatile. You can use it not only on your tomatoes but also all of your fruits and veggies. It’s particularly great for watermelon too. 

The NPK ratio of this fertilizer is 5-4-6. Since there’s not a drastic difference between the numbers, this fertilizer is pretty balanced to cater to all of your plant needs. 

3. The Old Farmer’s Almanac Organic Tomato & Vegetable Plant Food Fertilizer

Product Overview

Now there are a ton of fertilizers out there in the market which is labeled as ‘organic’. But how many of them guarantee this?

If you’re looking for a fertilizer that’s purely organic, look no further than this fertilizer from The Old Farmer’s Almanac. That’s because it’s an OMRI listed fertilizer.

In case you’re unsure of what that means, it proves that the fertilizer has been approved by the Organic Material Review Institute. So, when it comes to reliability, you’ll have no worries whatsoever. 

Another noteworthy feature is that this fertilizer contains a mix of slow and fast release granules. That means the soil can retain the fertilizer for a long time and show results.

Now, organic fertilizers often have a bad rep for being difficult to apply or having bad smells. But this fertilizer takes care of that too. Since it has no manure or harsh chemicals, there’s no scope of any odors.

Also, one 1.2 kg bag of fertilizer can cover up to 250 sq feet! What more so, the fertilizer provides continuous nutrition to the soil for 6 to 8 weeks. So you’re definitely getting your money’s worth. 

Last but not the least, the NPK ratio of this product is 8-4-8. With 8% nitrogen, you’re getting optimal growth and color on your leaves. 4% phosphorus ensures that you achieve healthy watermelons whereas the 8% potassium takes care of the roots.

4. Burpee Organic Tomato and Vegetable Granular Plant Food

Product Overview

Another fertilizer that we couldn’t go without mentioning is the Burpee Organic tomato and vegetable plant food. 

If you’re someone who likes to grow their own fruits and vegetables, you know how hard it gets to grow healthy ones. Sometimes, no matter how careful you are, the fruits end up being infested by bugs or just not healthy enough.

With this fertilizer, you can say goodbye to such woes. The granules in this start working on the roots quickly but also lasts up to 3 months. 

Another interesting feature of this fertilizer is that it contains microbes. These microbes are super beneficial for your plants and keep bad bacteria away.

By applying them to your watermelon plants, you can yield bigger and better fruits, minus the harmful chemicals that you can find on traditional fertilizers. Moreover, just like the previous fertilizer, this organic fertilizer from burpee is also OMRI Listed. 

A bag of fertilizer contains 4 lbs or 1.81 kg worth of product. So you can easily fertilize all of your vegetable and fruit plants and also have fertilizer left. 

This product comes with an NPK ratio of 3-6-4, contributing to the fast growth of the plants. A high 6% phosphorus content promotes the buildup of new cells, making the plants grow bigger and more beautiful. 

5. Dr. Earth Premium Gold Fertilizer 

Product Overview

If you want to take an organic fertilizer up a notch, consider investing in a Dr. Earth Premium Gold All-purpose fertilizer. That’s because it’s the only fertilizer in the USA that’s Non-GMO project verified. 

That means you’re guaranteed that your fertilizer is not only organic but also natural.

What’s the point of proving this statement? This fertilizer is also safe for you and your pets. It’s free of any chemicals, synthetic additives, or chicken manure that may contain GMOs.

Wondering then what’s in it? This Dr. Earth’s fertilizer contains human and feed grade ingredients. In other words, it’s a rich blend of multi-minerals, carbohydrates, proteins, and other trace elements that upgrades the soil to it’s healthiest version.

And we all know that healthy soil contributes to beautiful healthy plants, keeping an array of problems at bay. Moreover, these fertilizers are also sustainably made, in a way that doesn’t harm the environment.

One bag of fertilizer contains 12 lbs or 5.44 kgs of product. That amount can easily feed 165 sq feet of soil!

All you need to do is use one cup of fertilizer for every 10 sq feet area of your watermelon plants outdoors, and then water thoroughly. Repeat this process every 2 months, year-round, for optimal results.

Moreover, this fertilizer is a balance of all essential nutrients. No wonder, it has an NPK ratio of 4-4-4. 

Buying Guide

Now that we’ve talked about the good and bad about all the fertilizers, we hope you have an idea on which one to buy. If not, that’s alright too. 

After all, it can get quite confusing. To help you even further, we’ve listed out some crucial factors that you need to keep in mind when you decide to buy fertilizer. Let’s see what they are.

Release Factor

When deciding on fertilizer, you may be confused as to what kind to pick- Fast action fertilizers that show immediate results of fertilizers that are retained in the soil for months.

This depends entirely on your plant needs. If your plants hit a bug stump, or you fear that their health is deteriorating, a fast-action fertilizer may be best.

However, slow-release fertilizers may be best in the long term, for plants that don’t have any existing major concerns. 

The Right NPK Ratio

Now if you’re new to gardening, the various big numbers may have your brain in a jumble. If you’re confused about how much of which nutrients your plants need, here’s a quick tip. 

Watermelons do well with a high level of nitrogen fertilizer in the initial stages. However, once they reach adolescence, low nitrogen fertilizer will yield better results and harvest.

So ultimately, it depends on your plant needs and what growth stage your watermelon plant is in. 


Question: How do I make my watermelon sweeter when growing?

Answer: To ensure sweet watermelons, pick a seed variety known for its sweetness. Next, apply fertilizers regularly and also make sure that the environment is warm. Don’t forget to keep the soil moist by regular watering and pick the watermelons when they’re at their best stage.

Question: Do watermelons like coffee grounds?

Answer: Using raw coffee grinds on your watermelons could result in more bad than good since it could be too acidic for watermelons. However, mixing it with compost could give a growth boost to watermelons, but shouldn’t be used as a replacement for fertilizers. 


With that, we come to the end of our post. We hope you enjoyed this article and it helped you pick the fertilizer you’re going to use on your watermelons.

If you have any residual doubts on which is the Best Fertilizer for Watermelon, don’t forget to let us know in the comments below, and we’ll get back to you.

Until then, stay happy and safe!

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Celina Nance

It’s been a life-long wish of Celina Nance to have a lawn full of colorful flower beds. But living in Arizona city, that seems kind of impossible. But Celina Nance didn’t stop and created a full-form balcony garden instead. And she often shares stuff that she does/solves/innovates throughout the journey.

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