What is the Best Water-Soluble Fertilizer?

Written by Amir Tajer


Posted on June 17 2024

Home growers and commercial farmers alike are constantly looking for ways to make life easier while improving crop outcomes. The manner in which you feed your plants is one of the best ways to optimize growth cycles and encourage more bountiful harvests.

That’s why it’s worth investing in a high-quality water-soluble fertilizer.

Wait - what is a water-soluble fertilizer? More importantly, what is the best water-soluble fertilizer for vegetables, fruits, or anything in between? Your search ends here at Greenway Biotech.

Our water soluble fertilizer is sustainably sourced and meticulously crafted to deliver optimal results across a multitude of plants. Whether you’re looking for the best fruit tree fertilizer or the best organic vegetable fertilizer, you can count on us to deliver a safe, effective solution. Here are some of our top choices:

Not sure which is right for you? Read on below to learn more about the best organic water-soluble fertilizer, what makes this style the #1 choice for all types of gardeners, and how to actually use it. 

Or, get in touch with our customer service team and we’ll offer a personalized recommendation to point you in the right direction and set you up for success this growing season!

What is a Water Soluble Fertilizer? Pros and Cons to Consider

First, what is a water-soluble fertilizer? As the name suggests, these are compounds that dissolve completely in water, allowing nutrients to be delivered directly to plants in a liquid form. 

This method of fertilization is highly efficient, as it ensures that nutrients are immediately available to the plant roots, facilitating rapid absorption. While there are obvious benefits to this style, it’s important that you’re aware of potential drawbacks as well.

Pros of Water-Soluble Fertilizers:

  • Immediate Effect: The nutrients in water-soluble fertilizers are readily available to plants, which is particularly beneficial during critical growth phases.
  • Uniform Distribution: When applied via watering systems, these fertilizers provide uniform nutrient distribution, ensuring that each plant receives the same level of nutrition.
  • Versatility: They can be used for a variety of application methods, including foliar feeding and drip irrigation, making them adaptable to both small-scale gardens and large agricultural fields.
  • Control: Gardeners and farmers can easily adjust nutrient ratios and concentrations to meet specific plant needs, offering greater control over plant nutrition.

Cons of Water-Soluble Fertilizers:

  • Leaching Risk: If not applied carefully, these fertilizers can leach into the groundwater, potentially causing environmental pollution.
  • Frequent Application: Because the nutrients are so readily available, they can also be quickly depleted, requiring more frequent application than their slow-release counterparts.
  • Cost: Regular application can lead to higher costs over time compared to less frequent applications of slow-release fertilizers. You do get what you pay for, though, as the application is more straightforward, saving time (which is money, after all!).
  • Chemical Dependency: Overreliance on water-soluble fertilizers can lead to reduced soil fertility, as the natural soil ecosystem may be bypassed or diminished. You’ll need to use organic fertilizer to avoid this - the good news is we have water-soluble organic fertilizers to choose from here at Greenway Biotech.

What Nutrients are Included in These Fertilizers?

Greenway Biotech water soluble fertilizers for garden

One of the most common questions we get asked is in regards to the nutrient composition of water-soluble formulations. These are no different than any other type of fertilizer in that they provide the big 3 (NPK), and in some instances, secondary nutrients and micronutrients.

The most important are nitrogen (N), phosphorus (P), and potassium (K) - here’s the role each plays:

  • Nitrogen (N): Essential for the synthesis of proteins and for leaf and stem growth, giving plants their lush, green color. Extra important during the early stages of growth when energy needs are high.
  • Phosphorus (P): Supports energy transfer and photosynthesis, leading to the development of roots and flowers. It plays a role in transforming solar energy into chemical energy, aiding in plant maturation and the strength of the root system.
  • Potassium (K): Known for its role in water absorption and enzyme activation. Strengthens plants’ abilities to resist diseases and aids in the development of strong stems and overall vigor.

Understanding the optimal NPK ratio for your specific variety is one of the most important steps to feeding them what they need. But, they also need other nutrients in smaller quantities - these are known as secondary nutrients. These are three of the most essential:

  • Calcium: Important for cellular development and growth. It contributes to the stability and structure of plant walls.
  • Magnesium: A core component of chlorophyll. Pivotal for photosynthesis and helps in the creation of other vital plant nutrients.
  • Sulfur: Involved in the creation of vitamins and essential amino acids. Contributes to the flavor and odor in many plants.

Finally, there are also micronutrients your plants may need. While not all of these are necessary for every plant, here are some of the most prominent:

  • Iron is necessary for chlorophyll synthesis.
  • Manganese aids in the metabolism of chlorophyll and some enzymes.
  • Zinc influences growth hormones and enzyme systems.
  • Copper acts as a catalyst in photosynthesis.
  • Molybdenum is vital for nitrogen fixation.
  • Boron helps in cell wall formation and energy transfer.

Each nutrient has a specific role, contributing to a plant’s growth, health, fruit and flower production, and overall resilience. Take the time to research your crop’s specific nutritional needs to make sure you’re choosing the right water-soluble organic fertilizer.

What Plants Can Use Water-Soluble Fertilizer?

You may be wondering - can I even benefit from getting the best water-soluble fertilizer? Absolutely! 

These nutrient solutions are incredibly versatile and can be used for both indoor and outdoor gardening across a wide variety of plants. Here are some of the most common use cases:

  • Houseplants: Indoor plants often have limited access to natural soil nutrients, making water-soluble fertilizers particularly useful for promoting healthy growth and vibrant foliage. They can be easily applied through regular watering routines.
  • Vegetable Gardens: These fast-acting and efficient fertilizers are excellent for vegetables that need consistent nutrient levels to produce bountiful crops. They support rapid growth cycles, especially in fast-growing leafy greens like spinach and lettuce.
  • Flower Gardens: They can help produce more vibrant blooms and denser foliage in flowering plants. You can quickly address nutrient deficiencies that may prevent optimal blooming.
  • Container Plants: Nutrients can deplete quickly in pots and containers as they are not replenished naturally like in garden soil. Water-soluble fertilizers can replenish these nutrients at every watering, ensuring container plants remain healthy and vigorous.
  • Fruit Trees and Shrubs: These larger plants benefit from deep watering mixed with water-soluble fertilizers, which improves fruit yield and quality by ensuring that nutrients reach the root system.
  • Lawns: Water-soluble fertilizers are used in lawn care to promote lush, green growth across extensive areas efficiently. They are often applied using hose-end sprayers that distribute the fertilizer evenly.
  • Hydroponics: Plants grow without soil in these systems, making these types of hydroponic nutrients a must for all the necessary nutrients directly in the water solution.

Natural vs Chemical Water Soluble Fertilizers

You’ll come to a crossroads in your search for the best water-soluble fertilizer: should you go with an organic vs synthetic fertilizer

The obvious answer is to stick with a more natural solution given its impact on crop, environment, and consumer health. However, there’s more to the story than meets the eye. We’ll help you make the right choice below.

Natural Water-Soluble Fertilizers:

These are a sustainable option for enriching soil derived from organic sources such as animal manure, compost, or plant extracts. They not only supply essential nutrients but also improve soil structure and increase microbial activity, which enhances soil fertility over time.


  • Environmental Sustainability: Natural fertilizers are renewable and minimize the risk of chemical runoff that can harm local ecosystems.
  • Enhanced Soil Health: These fertilizers contribute organic matter that supports soil microbes for plant nutrient uptake. Healthy soil = healthy plants!
  • Safer for Plants: They are less likely to cause nutrient burn due to their gentle release of nutrients.
  • Better for Consumption: You won’t have to stress about residual chemical intake when you eat your fruits or veggies come harvest day - the crop tends to taste better when grown organically, too.


  • Lower Nutrient Concentration: They generally have lower nutrient levels compared to synthetic options, requiring larger quantities to achieve the same effect.
  • Variable Nutrient Ratios: The exact composition can vary between batches, making precise nutrient management challenging (unless you’re sourcing from a reliable, consistent source like Greenway Biotech!).

Chemical Water-Soluble Fertilizers:

These fertilizers are manufactured through chemical processes and are designed to provide a quick and controlled release of nutrients. Commonly used chemical fertilizers include urea, ammonium sulfate, and monopotassium phosphate.


  • Immediate Nutrient Availability: Chemical fertilizers are highly soluble, providing rapid nutrient uptake that is beneficial for fast-growing plants.
  • Consistency: They offer predictable and consistent nutrient ratios, essential for targeted fertilization practices.
  • High Efficiency: Smaller amounts can deliver larger doses of nutrients due to their concentrated formulas.


  • Environmental Impact: Overuse can lead to nutrient runoff, contributing to water pollution and ecosystem disruption such as algal blooms.
  • Soil Health Degradation: Prolonged use can lead to soil acidification and decreased microbial activity, potentially reducing soil fertility.
  • Potential for Plant Damage: Misapplication can result in nutrient burn or toxicity due to their high solubility and concentration.

Which is Right For You?

Ultimately, only you can determine whether you should go with a natural or synthetic solution. Each has its pros and cons, and fortunately, you don’t have to look far for either option. Greenway Biotech has both styles! So, without any further ado, let’s get into the best water-soluble fertilizer below.

What is the Best Water-Soluble Fertilizer?

So, what is the best water-soluble fertilizer? Now that we’ve covered everything you need to know about this type of nutrient solution it’s time we introduced you to some of the top picks. Choosing the right one is going to depend on how you grow and the specific crop at hand. When in doubt, reach out!


This is perhaps the best nitrogen-rich fertilizer as it contains 46% nitrogen, perfect for promoting lush vegetative growth. Its rapid solubility in water allows for swift absorption by plants, facilitating a quick greening response and sustained growth. 

Its ease of application through broadcasting, side-dressing, or fertigation, and its ability to integrate smoothly into different farming systems, make it a go-to choice for efficiency and effectiveness.

Ammonium Sulfate

This fertilizer offers a blend of 21% nitrogen and 24% sulfur. It works particularly well in alkaline soil conditions, enhancing the uptake of essential nutrients like nitrogen. 

Its highly soluble nature ensures quick availability to plants. It’s perfect for both soil-based and foliar applications, making it a versatile choice across various agricultural settings.

Boric Acid (Organic)

As a micro-nutrient fertilizer, boric acid facilitates the transfer of sugars and nutrients, which is essential for growth and yield. It's especially important for reproductive success in plants, influencing pollination and seed development. 

With a formulation that is easily soluble and efficient in small quantities, it corrects boron deficiencies effectively without risk of toxicity. It’s a must in your gardening arsenal if you’re growing plants/in conditions prone to boron deficiency.


This balanced blend of Nitrogen, calcium, magnesium, and iron (2-0-0) prevents common nutrient deficiencies such as blossom end rot in tomatoes and peppers and tip burn in leafy vegetables. 

The soluble form of Cal-Mag Plus ensures that these essential nutrients are quickly available to plants, enhancing overall health and boosting yields in a variety of crops

Calcium Nitrate

This fertilizer not only supplies essential nitrogen but also has 19% calcium to address deficiencies that could impact plant cellular function and strength. 

It’s highly soluble and efficient, perfect for use in hydroponic systems as well as traditional soil gardens. Across growing scenarios, it promotes healthy plant structure and resilience against diseases.

Ferrous Sulfate (Organic)

Ferrous Sulfate is key in chlorophyll synthesis, helping to correct iron deficiencies that cause yellowing of leaves (chlorosis). Its high solubility ensures that iron is readily available to plants, promoting vibrant, healthy growth. 

Suitable for a range of applications from lawns to vegetable gardens, its role extends beyond fertilization to include water treatment and as a colorant in various industrial applications. It’s one of our most popular picks for this reason.

Gypsum (Organic)

Unlike other options on our list of the best water-soluble fertilizers, gypsum offers a slow-release source of calcium and sulfur. It's especially useful for improving soil structure and combating sodic soil conditions. 

While not immediately soluble, its long-term benefits include improved water penetration, nutrient uptake enhancement, and better soil structure, making it an essential component for sustainable agricultural practices.

Crop Specific Fertilizers

Looking for something more specific, such as the best fertilizer for strawberries or the best fertilizer for tomatoes? We have specialty fertilizer for some of the most common crops:

These are just the tip of the iceberg. If you still aren’t seeing what you need, get in touch with our customer service team and we’ll help you find the perfect solution!


How to Use Water-Soluble Organic Fertilizer

Before wrapping up this guide to the best organic water soluble fertilizer, we want to set you up for success with some tips on effective application. From mixing to applying, storing, and more, here’s how to use water-soluble fertilizer.

Mixing Instructions

Always follow the label instructions for the correct water-to-fertilizer ratio. Most water-soluble fertilizers are designed to dissolve quickly in water to create a nutrient-rich solution that can be easily absorbed by plants.

Using warm water can help dissolve the fertilizer more thoroughly, ensuring that the nutrients are evenly distributed in the solution.

Depending on the optimal range for your plant’s nutrient uptake, you may need to adjust pH after mixing the fertilizer. This will prevent nutrient lockout which would otherwise lead to deficiencies.

Application Methods

There are a few different ways you can go about actually applying these fertilizers, either as a foliar spray or directly at the roots (Note: Not all of the fertilizers mentioned in this article are suitable as a foliar spray).

Foliar application involves spraying the fertilizer solution directly onto the leaves. It is highly effective because plants absorb nutrients through their leaves quickly. It’s ideal for correcting mid-season nutrient deficiencies.

On the other hand, applying the solution directly to the soil allows the roots to absorb the nutrients. This can be done using a watering can or through sophisticated drip irrigation systems, which help deliver the fertilizer solution directly to the root zone.

Always be sure to follow the application rates provided with the product of your choice. For example, our tomato fertilizer should be applied at a rate of ½ teaspoon per gallon of water. On the other hand, our ferrous sulfate solution should be applied at a rate of 1/2 to 1 cup per 100 square feet.

Timing and Frequency

Apply fertilizers in the early morning or late afternoon when temperatures are cooler to avoid nutrient evaporation and ensure maximum absorption.

It’s also essential that you’re delivering nutrients when your plants need them most, so follow a meticulous feeding schedule. You’ll typically want to feed numerous times over the course of your crop’s growth cycle. This could be as frequent as every 2-4 weeks.

Monitoring and Adjustments

Monitor plant response after application. Improved vigor and color indicate effective absorption, while signs of burning or leaf curling may suggest over-application. Depending on the plant’s response, you may need to adjust the concentration of the fertilizer solution. 

Storage and Handling

Keep the fertilizer in a cool, dry place to maintain its efficacy. Moisture can cause water-soluble fertilizers to clump, making them difficult to dissolve. Do not mix up more than you need and attempt to store it as a liquid.

Person applying greenway biotech azomite powder volcanic ash to potted plant

See What a Difference the Best Organic Water Soluble Fertilizer Can Make in Your Backyard Garden or Commercial Farm Today!

There you have it - everything you need to know about the best water-soluble fertilizer. These provide rapid, efficient nutrient delivery, enhancing plant growth and productivity through easy application methods. 

Whether you're aiming for lush foliage, vibrant blooms, or bountiful yields, the right fertilizer can elevate your gardening success to new heights. It’s just a few clicks away at Greenway Biotech, so what are you waiting for? 

Tap into the benefits of precision nutrition for your plants. Order your nutrient solution today and discover firsthand what a difference it can make in the vitality, yield, and quality of your crops!



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