hydroponic marijuana fertilizer

A Guide On Cannabis Nutrients For Hydroponic Systems

Are you sure you’re using the correct products for your hydroponic system? These will differ quite significantly from soil solutions. Make sure you know what to use, and in which quantities.


When growing without soil, nutrients will be a crucial factor to consider when trying to achieve the best yields possible. With the right combination, you’ll be sure to get the best buds in terms of quantity and quality.

In hydroponic systems, the nutrient solution you choose will replace the micro and macronutrients that soil would normally provide. The advantage of hydroponic growing, however, is that you can replicate a soil medium without the unpredictability.

The first thing you should look for when purchasing nutrients is the ratio of three essential nutrients: nitrogen, phosphorus, and potassium (N-P-K). These are the macronutrients. They are called this because they are absorbed in the largest quantities by the plant.

Nitrogen is responsible for leaf growth and pigmentation. When there is a lack of nitrogen, older leaves turn yellow and soft. This can lead to a lethal condition if not fixed in a timely fashion. Phosphorus is what you’ll need for the proper development of stems, roots, and flowers. Because of this, during the flowering stage, your plants will require more phosphorus to produce bountiful yields. A phosphorus deficiency during the flowering stage can affect the quantity and quality of your buds drastically, so be careful. Potassium is of slightly lesser importance, but still contributes to the development of the buds, stems, and roots. It also ensures that proteins are synthesised.


With so many brands and combinations of nutrients out there, which one is best for your grow? This is an important decision, but one you’ll be learning more and more about as you go. Only experience will help you assess the correct nutrients for your situation. It all depends on what you’re trying to achieve. But here are a few pointers to get you started.

Make sure that the bottles contain no organic matter; this will cause root problems and spur the formation of bacteria. The minerals you use should be chelated. This is when nutrients are covered by an organic molecule that is less sensitive to pH changes. This gives the plant a wider pH range in which it can properly absorb nutrients. And finally, the ideal NPK ratio will also be crucial.

NPK will be displayed on nutrient bottles as a ratio of 3 digits, each describing the percentage of the corresponding nutrient. The remaining percentage will be composed of micronutrients. The ratio of nutrients will change depending on the stage of growth. During the vegetative stage, your nitrogen value should be high, phosphorus should be medium-high, and your potassium, high too. When you move into flowering, make sure you decrease the nitrogen percentage. This should be kept low while the other two remain high.


There are some nutrients that are more easily absorbed by cannabis roots than others. Independently of the nutrient brand you choose, your plants can still face deficiencies if the pH is not correct.

Cannabis plants function improperly when the pH around the root zone moves into an undesirable range. This is why you need to be ready to act when you spot a deficiency. These tend to first show in the colour of the leaves. When they turn yellow, either you’re lacking nutrients, or the plant isn’t able to absorb the essentials it needs.

In hydroponic systems, nutrients tend to be better absorbed when the pH around the root zone is between 5.5-6.5. But the ideal value you should aim for is 5.7. When looking to dial-in your pH, don’t necessarily trust a pH-stabilising solution. This kind of product still requires your constant attention. You’ll be better off flushing your system every now and then before purchasing pH-adjusting products.


With hydroponic systems comes the obvious advantage of having more control over what the plant is absorbing. Having constant access to water and oxygen, you just have to control which nutrients you give your plants, and in what amounts. But using this more experimental system can also detract from some of the beauty of growing weed in a traditional way.

In a soil medium, manure can be added, which is a nutrient-rich material that will certainly improve the general health of your plant. This is something that a nutrient solution can’t replicate. Soil contains microbes that help turn organic material like guano, worm castings, etc. into usable nutrients for your plants. But in hydroponics, it is necessary to feed your plants the micro and macronutrients directly. Independently of the quality of your soil, you’ll always be needing extra supplements to obtain the best results. This is where hydroponic systems most differ from soil-based mediums.

Micronutrients like iron, copper, and magnesium are widely available in most soil mediums. Therefore, hydro solutions must contain more of these to compensate. Soil also contains more nitrogen. This is why hydro nutrients receive a hefty dose of nitrogen in the vegetative stage.


The debate between growing in soil vs using a hydroponic system continues to unfold. We assume you’ve already made the difficult choice and are ready to commit to your method. Once the commitment is established, you’ll have to make the decision of purchasing the best products for your situation. These will depend on personal preference, level of experience, and commitment to the grow operation. You might prefer nutrient solutions that require less attention, or you might be looking to control every single factor that can influence your yields.

These are all decisions you’ll have to make on your own, independently of what you read. No matter your level of experience, you’ll always run into problems that will likely require your intervention. This is how you learn. Just don’t let the death of a plant demotivate you or stop you from trying again. Hydroponic systems have the potential of yielding ridiculously potent, high-quality buds. The effort will pay off.

Good luck with your system and just remember that attention is key. As long as you’re confident in reading your plant’s signals, you shouldn’t worry. Have a good harvest.

Learn more about what to look for when purchasing nutrients for your hydro system and how these differ from a soil medium.

Best Hydroponic Nutrients for Weed in 2020

We reviewed hundreds of nutrients available on the market today as of July 2020 and created a simple list to help you pick the best nutrients for your grow.

When it comes to a hydroponic or soil grow, these nutrients are the best in market when it comes to growing your cannabis or weed grow with the most trusted, reliable, and affordable nutrient brands in the market. We also compiled a list of frequently asked questions for cannabis growers to understand the what to look for with nutrients and how the process actually works.

Have a question about any of these nutrients? Ask us in the comments!

Best Cannabis Nutrients For Growing Weed

  • 1 Best Nutrients for Weed: Quick Product Comparison Chart
  • 2 Things To Consider Before Buying
  • 3 Reviews of the Best Hydroponic Nutrients for Growing Weed 2020
    • 3.1 General Hydroponics Flora Grow
    • 3.2 Runner Up: Advanced Nutrients Bloom/a>
    • 3.3 Fox Farm – Big Bloom, Grow Big, Tiger Bloom
    • 3.4 Humboldt’s Secret Base A & B
    • 3.5 Dyna-Gro DYFLO008 Foliage Pro
    • 3.6 Orga Grow Holland
    • 3.7 CANNA Coco A&B
    • 3.8 House & Garden Aqua Flakes A&B
    • 3.9 Botanicare Liquid Karma
    • 3.10 General Hydroponics GH Gardening Flora
  • 4 Frequently Asked Questions
    • 4.1 What Should I Know About Nutrients?
    • 4.2 What Do Cannabis Plants Need To Grow And Thrive?
    • 4.3 What About Micronutrients
    • 4.4 Growing Cannabis Plants Using Hydroponics
    • 4.5 Growing Cannabis Plants In Soil
    • 4.6 Nutrients For Each Stage Of Growth
    • 4.7 Guarding Against Feeding Problems
    • 4.8 Getting The pH Balance Right
    • 4.9 Growing Healthy Plants

Best Hydroponic Nutrients For Weed 2020: Product Comparison Chart

Things to consider before buying

There are a couple of things you absolutely need to consider before choosing the best nutrients for growing weed:

1) Nutrients: It’s imperative when researching nutrients and buying products that you ensure you look at the labels. Almost all nutrients in the market should have a label and should indicate the three core nutrients: Nitrogen, Phosphorus and Potassium (NPK). For example if a bottle indicates the following numbers: 3-1-3, this shows the different levels (Nitrogen, 3), (Phosphorus, 1), and (Potassium, 3). To be “complete”, a hydroponic nutrient needs to go beyond NPKs and have all of the essential elements for plant growth:

  • – Nitrogen (N)
  • – Potassium (K)
  • – Phosphorus (P)
  • – Magnesium (Mg)
  • – Iron (Fe)
  • – Calcium (Ca)
  • – Sulphur (S)
  • – Zinc (Zn)
  • – Chlorine (Cl)
  • – Boron (B)
  • – Manganese (Mn)
  • – Copper (Cu)
  • – Molybdate (Mo)

2) NPK Ratios:

When thinking about starting your grow, you’ll want to understand the amount of nutrients you’ll need to shower your plants with. You’ll find differing opinions everywhere you research, but from our experience as well as the guidance from very well respected growers, the table below is a good illustration of the amount of nutrients you should provide your plants throughout each stage.

Vegetative Stage Flowering Stage
High Nitrogen Low Nitrogen
Medium Phosphorus Medium to High Phosphorus
High Potassium High Potassium

Remember to keep your nutrient ratio balanced – it’s important to understand where phosphorus or potassium is needed for healthy growth, otherwise, you risk your plants dying unexpectedly.

3) Hydroponic or Soil: You’ll want to understand the use cases for nutrients when it comes to hydroponic or soil grows. Hydroponics setups without soil is used by large-scale growers that are primarily indoors. Many of the cannabis/weed related nutrients are sold for hydroponic set ups. One important point to note is that if you are using organic nutrients, it is not recommended to use organic nutrients with hydroponic setups – it can ruin your water/grow with bacteria. All of the liquid nutrients below can be used for hydroponic growing and soil grows. Again – it is perfectly fine to use these hydroponic nutrients in soil and vice versa, these are all perfect for all types of grow when it comes to your cannabis.

Reviews of the Best Hydroponic Nutrients for Weed in 2020

Editor’s Choice: General Hydroponics Flora Grow

Average Amazon Review: 4.6 stars

# of Amazon Reviews: 903 +

Runner Up: Advanced Nutrients Bloom, Micro & Grow

Average Amazon Review: 4.5 stars

# of Amazon Reviews: 260+

Fox Farm FX14049 Liquid Nutrients

Foxfarm offers many different types of soil mixes including a soil conditioner if you are in need. This product is complete with micro-nutrient and macro-nutrient formulations and have a nice blend of natural fertilizers. This product is easily mixed with water for easy growing.

At Productiongrower, we love this product because it’s the perfect one for intro hydro gardeners as well as more experienced ones. It is a convenient 3-pack of the top liquid fertilizer products for hydroponics. It’s easy to use since you use them in sequence all season long. You should start with the Grow Big for abundant green growth and then switch over to the Tiger Bloom when you start to see your first buds grow. Lastly, use the Big Bloom throughout each growing cycle to heal and nourish the root systems.

Average Amazon Review: 4.5 stars

# of Amazon Reviews: 726+

Humboldt’s Secret Base – Most Reliable

Average Amazon Review: 4 stars

# of Amazon Reviews: 36+

Dyna-Gro DYFLO008 – Low Budget Choice

Average Amazon Review: Not Reviewed Yet

# of Amazon Reviews: Not Reviewed Yet

Orga Grow Holland

Average Amazon Review: 4 stars

# of Amazon Reviews: 10+


Average Amazon Review: 4 stars

# of Amazon Reviews: 52+

House & Garden Aqua Flakes

Average Amazon Review: 4.6 stars

# of Amazon Reviews: 7+

Botanicare Liquid Karma – Best Longevity

Average Amazon Review: 4.4 stars

# of Amazon Reviews: 110+

General Hydroponics Flora Nectar Sugar Cane

Average Amazon Review: 4.6 stars

# of Amazon Reviews: 121+

Frequently Asked Questions

What Should I Know About Nutrients?

If you’re growing cannabis for the first time, selecting the right nutrients for your plants can be a challenge. There are lots of options on the market, so how do you make the right decision?

The key to choosing nutrients lies in understanding precisely what cannabis plants requirement and in being aware of how they absorb nutrients and utilize them. When you have this knowledge at your fingertips, you can make a confident decision about which products to buy without wasting your money.

What Do Cannabis Plants Need To Grow And Thrive?

Cannabis plants require a number of collective elements known as “macronutrients”. These include a number of mineral and non-mineral elements. Some come from the water, some from the air and some from the soil in which the plants are grown.

These nutrients come from the soil:

  • – Phosphorus
  • – Nitrogen
  • – Calcium
  • – Potassium
  • – Sulfur
  • – Magnesium

These nutrients come from the water and air:

  • – Oxygen
  • – Hydrogen
  • – Carbon

When you buy fertilizers or nutrient solutions, you’ll see 3 numbers on the packaging. This will show the composition of potassium, phosphorus and nitrogen inside the product. The nitrogen content will be listed first, followed by the phosphorus content and finally the potassium content.

What About Micronutrients?

Cannabis plants also require micronutrients. These are required in much smaller amounts. These minerals include:

  • – Zinc
  • – Manganese
  • – Iron
  • – Molybdenum
  • – Cobalt
  • – Chlorine
  • – Boron
  • – Silicon
  • – Copper

Although cannabis plants don’t need a lot of any of these elements, they’re still essential to the plant’s growth and overall health.

Growing Cannabis Plants Using Hydroponics

If you’re going to use hydroponics to grow cannabis, you’ll need specific nutrients for your plants. You won’t be using soil, therefore, you’ll be using a substrate such as coco coir or rockwool. Be aware that lots of cannabis potting soils are soilless blends and therefore, you could be growing your plants hydroponically even when you’re using potting soil.

It’s because of this that most nutrients which are sold for growing cannabis plants are those for hydroponic growing techniques. These are made from concentrated mineral salt. Sometimes they come in powder form but usually, they are liquids.

There are two types of nutrient solution available for hydroponic growing – Bloom solutions which have a high phosphorus level to aid flower development, and Grow solutions which have a high nitrogen level to support vegetative growth.

When you apply hydroponic nutrients, you need to take a lot of care. This is because giving too much to your plants can damage them, or even kill them. Start at around 25% of the recommended level then work up gradually to the full strength.

Growing Cannabis Plants In Soil

When you grow cannabis plants in regular soil, you will need specific nutrients. Soil is different from hydroponic soilless blends because it contains organic non-inert matter such as manure, worm castings, compost and humus. These contain a lot of micronutrients and macronutrients. Lots of these substances’ nutrient value is insoluble, however, and therefore have to be processed by fungi and microbes living in the soil in order to be useful to the cannabis plant. It is less common to see non-organic nutrients for growing cannabis plants in soil since they build up rapidly in soil, causing damage to the soil-life and preventing nutrients and water from being taken into the roots. On the other hand, organic nutrients and fertilizers for cannabis plants are more commonly seen. These contain fewer nutrients which are immediately soluble together with elements which have benefits for organisms naturally in the soil. Therefore, if you’re going to grow your plants in soil, using organic nutrients and fertilizers is always advised.

There are a number of affordable organic fertilizers which you can use. These include fish and blood meal which offers plenty of nitrogen, bat guano and bone meal which supplies phosphorus, kelp meal and wood ash to supply potassium, Epsom salts which supply sulfur and magnesium, and dolomite lime which supplies magnesium and calcium. You can buy the majority of these in a garden center. All you need to do is mix them into your soil before you pot your plants. When you do this properly, watering will be all that’s required, along with adding carbohydrates occasionally. Some soil blends can also be bought which contain the ideal mix of those ingredients for greater convenience.

Nutrients For Each Stage Of Growth

Every stage of the life of your cannabis plants requires nutrients which are slightly different.

During its seedling stage, your plant probably won’t need any extra nutrients if you’re growing in soil as long as that soil is rich. If you’re growing using an artificial medium, you might want to use seedling nutrition and root boosters.

In the vegetative phase, your plants will require high levels of potassium and nitrogen as well as a moderate amount of phosphorus.

When your plants reach their flowering stage, you’ll need to reduce the nitrogen levels drastically, but increase the amount of phosphorus and maintain the potassium level. When you choose a Bloom fertilizer, the nutrients will be perfectly balanced for this stage of growth.

Guarding Against Feeding Problems

When you’re growing cannabis, caution is always recommended. If you use too many nutrients, you could damage your plants. Only add nutrients to the water every alternate watering and half the doses if you’re in any doubt.

If you notice any changes in your plant’s color or appearance, your plant is experiencing a feeding problem. Nutrient imbalances are signaled by yellowing and drooping leaves, leaves with irregular dimensions or shapes, burnt edges and brown spots.

If you adjust the nutrient balance and still experience a problem try flushing pure water through the soil for several days before starting again with a half dose of nutrient mix.

Getting The pH Balance Right

If the pH level is wrong, the plants can’t get the nutrients they need to grow and thrive, even if you add the right mix of nutrients to your water. Therefore, monitoring your pH levels is vital.

Growing Healthy Plants

When you’re growing cannabis plants for the first time, erring on the side of caution is always important. However, follow this advice and you should find that, as long as you use the right nutrients for the medium you are using, your plants meet all your expectations.

Updated: July 16, 2020 Written by Max Anderson

We reviewed hundreds of nutrients available on the market today as of July 2020 and created a simple list to help you pick the best nutrients for your grow. When it comes to a hydroponic or soil grow, these nutrients are the best in market when it comes to growing your cannabis or weed grow with the most trusted, reliable, and affordable nutrient brands in the market. ]]>