How To Calculate Liquid Fertilizer Rates

You need to know how to calculate liquid fertilizer rates using formulas, and not just how to measure fertilizers. Remember that fertilizers will only be able to do their job well if you use them appropriately for your garden and plants. One can assume that fertilizer application will only be optimal if you know the correct rate and measurement. 

More so, proper fertilizer management plays a significant impact on the environment and other living things close to the area. Those who need to use liquid fertilizer can do basic calculations to determine the rate themselves. And as time goes on, you can get used to the concepts, making rate calculations almost like second nature. 


How To Calculate Liquid Fertilizer Rates

Comprehensive Guide On How To Calculate Liquid Fertilizer Rates


Step #1. Understand the formula

The first step in calculating liquid fertilizer rates is understanding the formula. It might be overwhelming to read the formula upon a glance, but it is straightforward. Over time, you’ll get comfortable in inserting the values. For example, read the label to find the N-P2O5-K2O content of your fertilizer. 

You’ll also need to do a soil test, which is crucial before handling fertilizers. This will let you know your target rate and use the ideal fertilizer that will provide your plants’ needs. The third part of the formula is the total area of where you’ll use the fertilizer, which is self-explanatory. 

And lastly, what differentiates a liquid fertilizer rate from other rates is that you’ll also need to know the material’s density or weight. This is applicable only if you’re using a liquid fertilizer. Understanding these four values will help you apply the formula and calculate it without issues. 


Step #2. Apply the formula


Example #1.

To further help you understand the formula, let us use an example of calculating the liquid nitrogen fertilizer rate for a crop like corn. Using the formula, you will find the N application rate in gallons per acre and the amount you’ll need to apply 160 pounds of N on the area. You will need the values mentioned earlier, which means you should be aware that a 30% UAN liquid N fertilizer will suffice for 500 acres of corn. 

In this example, 10.86 pounds per gallon of fertilizer contains 30% nitrogen, which means you’ll get 0.30 pounds of N per pound of the fertilizer. One can simplify the calculation as 10.86 pounds per gallon multiplied by 0.30 pound Nitrogen per pound of fertilizer, and you’ll get the pound of N per gallon of fertilizer. 

You will also get the gallon of UAN per acre by dividing 160 by the amount you’ve had previously. Using the values from the previous two computations, you can get the tons for 500 acres. Overall, the calculation for liquid fertilizer rate is similar to how you’d compute the rate of dry fertilizers. 

Still, you’ll also account for the liquid fertilizer’s weight to find out its nutrient content.


Example #2.

If you’re still confused with using and applying the formula, a simplified equation would be multiplying the required nutrient application rate by 100 and dividing it by the percent nutrient in the fertilizer multiplied by the fertilizer weight. Let’s say that you need to apply 15 pounds of nitrogen using a liquid fertilizer with 30% nitrogen per weight, and the weight of UAN is 10.86 pounds per gallon. How can you use the formula?

You’ll get the fertilizer rate first, which means multiplying 15 by 100 and dividing it by 30. You’ll then get 50 pounds, and you’ll divide this by 10.86. Therefore, you will need 4.6 gallons of liquid fertilizer. 


How To Calculate Nutrient Requirements

Besides the liquid fertlizer rate, you also want to know how to calculate the nutrient requirements. Remember that you will only get the fertilizer’s correct rate if you know the crop nutrient requirements. Therefore, do a soil test first to ensure that you’ll meet the goals of your garden’s productivity. 

Remember that over time, the nutrients in the soil gets depleted. Some nutrients require a yearly application, while others require more frequent addition. An annual application of phosphorus and potassium should suffice, but nitrogen might be more periodic. 

If you’re growing in the greenhouse, you also need to adjust the amounts because the fertilizer recommendations are commonly used for large areas. You don’t want to guess the amounts due to the risk of over-fertilizing and under-fertilizing. You can use a simple equation of pounds recommended per 1000 square feet multiplied by square footage divided by 1000 square feet. 



Knowing and calculating fertilizer rates is crucial to avoid over-fertilizing and under-fertilizing. You can learn how to calculate liquid fertilizer rates by understanding the formula and how to apply the values. While it can be daunting to see how lengthy the formula is, it’s straightforward. 

One can simplify it into the required nutrient application rate multiplied by 100 and divided by the percent nutrient in fertilizer multiplied by the fertilizer weight. You’ll be taking the liquid fertilizer’s weight into account because this pertains to its nutrient content. Additionally, don’t forget the importance of soil test before calculations because it will ensure your plants’ fertilizer needs and avoid problems. 

With a proper understanding of the values and the formula itself, you should be able to calculate the rate of your liquid fertilizer without confusion. You can check out different examples from university extensions as well. 


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How To Prevent Root Rot In Hydroponics: 3 Useful Tips

If you’re a newbie gardener who’s looking to find ways to hone your skills, you’d want to learn how to prevent root rot in hydroponics even before this problem affects your plants.

Hydroponics can be advantageous to crops in more ways than one. However, it also comes with risks of diseases, such as root rot, which can be destructive or even lethal to your plants.

Unfortunately, there are no effective methods to recover the wilted parts that were affected by the root rot once it hits your plants. The only thing you can do if you do not want this catastrophe to befall your crops is to prevent it before it happens. Read on to learn more about this subject.


What is Root Rot?

Root rot is a disease that attacks the plant roots and causes them to suffer decay. This usually happens when a lack of oxygen supply occurs in the substrate.

To give you an idea, think about plant roots that are submerged in water that only has a little oxygen in it. Over time, the plant suffocates and dies.

Aside from rot and decay, this disease also leads to the proliferation of fungi that are naturally present in the soil. These include Rhizoctonia, Alternaria, Pythium, Botrytis, Fusarium, or Phytophthora. As soon as fungi colonies start to grow, they tend to target the weakened roots and infect your precious plant babies.

Once the plant becomes infected, they won’t be able to take in what they need to grow – water, oxygen, and other nutrients. When this happens, it won’t be long before the plant dies.


What is Hydroponics?

In case you’re not aware, the term hydroponic is derived from a Latin word that means “working water”. To put it simply, hydroponics is an art that involves growing various types of plants without soil. If you’re like most people, the first thing that comes to mind when somebody talks about hydroponics would be a picture of plants with roots suspended into the water without using any type of growing medium.


Avoiding Root Rot in Hydroponic Systems

Detecting and identifying root rot can be tricky. When your plants get infected, their leaves and roots gradually wither until the whole crop itself dies from the lack of nutrients, which is a common symptom of many diseases.


What causes root rot in hydroponics?

One of the requirements in hydroponics systems is oxygen. Without it, your plants are basically on the road to death. On the other hand, lack of such is one of the major triggers for root rot, and it must be avoided at all costs.

Just like when planting in soil, you loosen up the ground so that your plants’ roots can have their required intake of oxygen. That is the case for crops grown in aqueous solutions as well. If they cannot breathe, they would not be able to grow.

Another agent for root rot is the temperature. The last thing you would want in your system are parasites that leech nutrients intended for your plants and infect the water during the process. In common terms, these fungi are called molds.

One of the best breeding grounds for these is warm and moist areas. For this reason, if the water temperature inside your reservoir is high, then you are susceptible to it. Something as minor as letting the solutions exposed to sunlight can already be a risk factor.


3 Useful Tips on How to prevent root rot in hydroponics

There is good news! Root rot in hydroponics can be prevented! Just follow these tips:

Tip#1: Use the right air pump

If you do not want root rot to affect your plants, you merely have to avoid its causes. If you need oxygen, keep the water bubbling by providing an air pump of appropriate size, and also give importance to proper ventilation in the room.


Tip #2: Maintain the temperature

The temperature should be maintained within the 70 to 80 degrees F range. Get rid of any materials that can make your system vulnerable to infections, and make sure not to disturb your crops while they are trying to grow.


Tip #3: Get rid of the rotten parts

However, if you failed in preventing the disease, then the rotten parts should be removed immediately. Cut them off as there is no chance of reviving them, and focus on the potential new growth instead. Fix your hydroponics system and eliminate the risks.


Why Give Greenhouse Gardening a Try?

Greenhouse gardening offers numerous benefits to greens aficionados who dare to take their gardening experience to the next level. Aside from acting as a shield against the effects of inclement weather, a mini, hobby, or semi-pro greenhouse can also serve as a protective layer that keeps harmful bugs and critters at bay.

What’s more, its enclosed structure allows you to control your plants’ growing conditions including the temperature, light, moisture, and ventilation of the greenhouse’s internal environment. With a controlled environment, you’ll be able to extend growing seasons and grow plants that aren’t native to your area.



No matter how well-informed you are about how to prevent root rot in hydroponics, you cannot completely eradicate the risks. Therefore, to avoid the worst-case scenario, you should be prepared to sacrifice the infected for the sake of others. While you’re at it, consider trying your hand at greenhouse gardening as well.


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