How To Add Nitrogen To Hydroponics (Gardener Advice)

There are many types of fertilizers and nutrients that you can use to feed your hydroponics system. The type you choose depends on what plant you want to grow and how much effort you want to put into the process. 

In this article, we’ll go over some common additives used in hydroponics gardening as well as their benefits/drawbacks so you can make an informed decision about which one works best for you!

How To Mix Hydroponic Nutrients THE RIGHT WAY

Always use high-quality nutrient solutions with the proper balance of essential macro and micronutrients.
Monitor nutrient levels regularly and adjust them as needed, depending on the growth stage and type of plants you’re growing.
Check pH levels frequently and adjust them to maintain the ideal range for your plants.
Use reliable sources to learn about hydroponic nutrient mixing and make sure to follow the recommended ratios and dosages.
Avoid nutrient deficiencies by keeping an eye on the health of the plants and rectifying any deficiencies immediately.

Liquid Fish Emulsion

If you’ve ever eaten sushi or sashimi, you’re already familiar with fish emulsion. Fish emulsion is a liquid fertilizer made from the waste of fish processing plants that can be bought in concentrate form. 

It’s used to supplement nitrogen in the soil of plants grown from seeds and cuttings. The process for adding liquid fish emulsion to your hydroponic setup is very straightforward: just add it to water and dilute as needed!

Liquid fish emulsion is very handy because it provides nitrogen in such high concentrations that you don’t need an expensive test kit before adding it to your setup—you’ll know if there are too many nutrients by how well your plants grow!

To add nitrogen to your hydroponics system, you can use different methods such as dry/powder nutrients or liquid nutrients. Our gardener advice guide provides more insights into how to add nitrogen to your hydroponic system, along with the recommended dosages and tips for maintenance.

Solid Fish Meal

Solid fish meal is a high-protein, nitrogen-rich organic fertilizer. It’s made from the dried, ground remains of fish that have been processed through a heat treatment at high temperatures. T

his process preserves the nutrients contained within the fish and makes them easily accessible to plants when they’re added to your hydroponic system or garden soil.

Solid fish meal can be used in either hydroponic systems or non-hydroponic gardens.

Liquid Fish KELP

Liquid Fish KELP is a liquid fertilizer that is made from fish oil, water and salt. It’s used to promote the growth of plants. 

Liquid Fish KELP contains all the nutrients in fish emulsion and is available in bottles or buckets for home use.

Liquid fish emulsion (LFE) is a slow release fertilizer that can be used on all plants at any growth stage. The nitrogen in LFE comes from natural proteins found in fish oil, so you don’t have to worry about introducing unknown chemicals into your garden

The nitrogen content of this product should not be more than 4% by volume if using it as a foliar spray or dressing; however, if using it as an irrigation solution then increase this amount up to 8%.

Hydroponics systems require certain nutrients in order to maintain healthy plants. If you’re considering setting up a hydroponics system, make sure to check out our expert advice guide on how to do it properly. This guide covers everything from selecting the right hydroponics system to choosing the right plants and nutrients to use.

Alfalfa Meal

  • Alfalfa meal is an excellent source of nitrogen, trace minerals and can be used to slow-release nutrients into the soil.
  • Alfalfa meal contains potassium and calcium which are both essential for plant growth. It also has a high protein content as well as being high in magnesium, sulfur, phosphorus and boron.
  • Alfalfa meal is a slow release fertilizer that will last much longer than other types because it does not dissolve easily in water so it won’t be washed away by excess water or rain showers.


Crustations are an excellent source of nitrogen and other nutrients for your hydroponic garden. They’re a byproduct of the lobster industry and contain over 70 percent protein, making them an excellent supplement to your plants’ diet. 

Crustations also contain calcium and magnesium which are essential elements for plant growth.

In addition to being rich in nitrogen, amino acids and proteins, crustations are also high in trace minerals such as zinc, copper, selenium and manganese that you may not find in other fertilizers. 

These additional nutrients will help give your plants a boost when they’re struggling with disease or pests that don’t respond well to chemicals like pesticides.

Crab Shells

  • Crab shells (and other crustacean shells) are high in calcium, phosphorus, and magnesium.
  • Crustaceans don’t need the nutrients in their shells to survive, so they will shed them when they molt.
  • You can get crab shells from a seafood market or from a friend who likes to eat crabs!

The most common way to use crab shells is by putting them directly into your hydro setup. However, you can also put them in an airtight container with some water and allow them to soak for 24 hours before using. 

This method works well if you have a lot of crabs or other shellfish available because it makes it easier for your plants to absorb the nutrients from the shells due to increased surface area contact between plant roots and the material being soaked.”

Adjusting the PPM (Parts Per Million) is an important aspect of hydroponics, as it helps to regulate the nutrients in your system. Check out our expert advice guide to learn more about how to adjust PPM in your hydroponics system, the tools required, and the best practices to keep it running smoothly.

Soybean Meal

Soybean meal is a high-protein supplement that has been processed into a powdery form. It can be used as an organic fertilizer, soil conditioner and compost ingredient because it contains the essential nutrients needed for plant growth in one easy-to-use package.

Soybean meal tends to be better suited for long-term use than other forms of nitrogen, as it breaks down more slowly and evenly over time. Additionally, soybean meal contains significant amounts of phosphorus, potassium and sulfur all important nutrients for plants’ growth cycle.

Cottonseed meal

Cottonseed meal also known as cotton seed flour, is a byproduct of cotton ginning. The seeds are dried and then crushed into a powder. 

Cottonseed meal contains up to 60 percent protein, which makes it a great food source for houseplants, vegetables and fruiting plants. Another benefit of using cottonseed meal is its ability to help promote root development in your hydroponics system.

Cottonseed meal can be used in all stages of plant growth: seedlings, vegetative growth and flowering plants.

Nutrient levels in the hydroponics system need to be adjusted from time to time. Our expert advice guide provides tips on how to identify nutrient deficiencies, and how to adjust nutrient levels to ensure that your plants stay healthy and thrive.

Bone Meal

Bone meal is a good source of nitrogen, phosphorus, calcium and magnesium. It also contains sulfur, potassium and many other trace minerals that are important for plant growth. Bone meal can be used in soil or hydro systems to supply nutrients for the plants.

Bone meal is a good source of nitrogen because it contains about 10% protein (N), which is needed by your plants to make amino acids and proteins necessary for their growth. Phosphorus helps promote root growth while calcium aids photosynthesis. 

Sulfur plays an important role in root development and flower production. Potassium promotes overall health while trace minerals help maintain healthy roots

Blood Meal

Blood Meal is a byproduct of the slaughtering process. It’s high in nitrogen and phosphorus and can be used as a slow-release fertilizer for your plants. It is an organic source of nitrogen that works well in hydroponics gardens because it provides long-lasting nutrients to help your plants thrive.

The pH level in your hydroponics system is a critical factor that affects the nutrient uptake of your plants. Our guide on adjusting hydroponic pH covers the essentials of maintaining proper pH levels in hydroponics systems, including the tools and techniques required to balance pH levels in the system.

Hoof and Horn Meal

Hoof and Horn Meal is a popular slow release source of nitrogen, calcium and phosphorus. It contains high levels of all three nutrients.

It’s especially useful for hydroponic systems because it releases these nutrients over time, so you can add less Hoof and Horn Meal than other fertilizers to get the same effect.

Feathers and Feather meal (slow release)

Feathers are a good source of N and P. Feather meal is a slow release fertilizer, it is also high in nitrogen which makes it suitable for use as a base or top dressing on plants. 

Feather meal also contains other nutrients such as amino acids and phosphorus, this makes it an excellent soil conditioner that provides plants with additional nutrients at the beginning or end of their growth cycle.

Feathers and Feather Meal (Slow Release) Table

Slow release of nitrogen and phosphorusBreakdown time can vary depending on the type of feather meal
High in nitrogen concentrationOverapplication can lead to plants burning or stunted growth
Can improve soil structure and water retentionThe sourcing of the feathers may raise ethical concerns
Can be an organic and cost-effective optionThe nitrogen content can vary depending on the drying process and quality of the source

Bat Guano (hard to find organic – mostly high in P)

Bat guano is a by-product of the process bats use to digest their food. It’s rich in nitrogen and phosphorous, which makes it great for growing plants. It can be used on both soil and hydroponics systems because it contains so many nutrients.

Bat guano is also organic, meaning it’s a natural fertilizer that won’t harm your plants or add any extra chemicals to your garden. If you’re looking for an all-natural way to feed your plants, bat guano should definitely be on your list!

In addition to being naturally rich in N and P, bat guano has other benefits as well:

Dry Chicken Manuer pellets (slow release)

If you’re looking for a slow-release source of nitrogen, look no further than dry chicken manure pellets. 

These are made from dehydrated chicken manure mixed with sawdust or other ingredients to provide moisture-retention and prevent caking. They can be used as a soil amendment (mixing them into your existing soil), as well as an additive to potting soils or substrate mixes.

Dry Chicken Manure Pellets (Slow Release) Table

Slow release of nitrogenStrong odor that may attract pests or animals
High in nitrogen concentrationOverapplication can lead to the burning of the plants
Easy to apply and spread over timeNeed to be stored in a dry place to prevent clumping
Improves soil quality over timeInitial cost can be high compared to other options
Can be an organic and sustainable optionThe nitrogen content can vary depending on the brand


With so many options on how to add nitrogen, it can be hard to choose what fertilizer will work best for your plants. 

If you’re looking for one that’s easy and doesn’t require any special equipment, then fish emulsion is a great choice! It’s also a great way to get your feet wet before diving into something more complicated like solid fish meal or crab shell powder.

Further Reading

Here are some other useful resources you can check out to learn more about hydroponic nutrient mixing:

ZipGrow’s guide provides a detailed explanation of how to mix hydroponic nutrients for various types of hydroponic systems.

WikiHow’s article covers the basics of hydroponic nutrient mixing, including the types of nutrients you’ll need and how to properly mix them.

Home Guides SF Gate’s article provides a clear explanation of the key elements to creating a successful nutrient mixture for hydroponic gardening.


What are hydroponic nutrients, and why are they important?

Hydroponic nutrients are the essential minerals and other elements that plants need to grow, thrive, and produce fruit or vegetables in a hydroponics system. These nutrients are critical because hydroponic systems do not rely on soil to provide plants with key nutrients.

What are the different types of hydroponic nutrients?

Hydroponic nutrients can be broadly categorized into three types – primary, secondary, and micronutrients. Primary nutrients include nitrogen (N), phosphorus (P), and potassium (K), while secondary nutrients include calcium, magnesium, and sulfur. Micronutrients are essential elements like iron, copper, zinc, and manganese that are required in much smaller amounts.

How can I measure the nutrient levels in my hydroponic system?

One of the most accurate methods to measure nutrient levels is through Electrical Conductivity (EC) measurements, which measure the concentration of minerals in a solution. Another popular method for measuring nutrient levels in hydroponic systems is using Total Dissolved Solids (TDS) meters, which measure the total amount of minerals in a solution.

How often should I adjust the nutrient levels in my hydroponic system?

The ideal frequency of adjusting nutrient levels in your hydroponic system depends on several factors, such as the type of plants you’re growing, the system you’re using, and the stage of the plant’s growth. However, some general guidelines suggest adjusting nutrient levels every 7-10 days or after a complete nutrient cycle.

How can I avoid nutrient deficiencies in my hydroponic system?

One of the most effective ways to avoid nutrient deficiencies is by using high-quality nutrient solutions that have the ideal amount of essential macro and micronutrients. Additionally, it’s important to monitor nutrient levels and maintain the correct pH levels to avoid any adverse effects on the plant’s growth. Keeping a regular check on the plants will also help in identifying nutrient deficiencies and rectifying them immediately.