Fertilizers are products that you use to make sure that the plants that you are growing are well-supplied with essential mineral elements that they need.
You often fertilize plants outside and for that purpose, you use conventional fertilizers. These products come in larger bags and are spread out by hand or using spreaders.
When it comes to fertilizing your indoor cannabis plants, those conventional fertilizers may not be the best choice. Fear not, we have a few options for you.
The products we have selected for you are all-in-one solutions for the serious indoor marijuana grower. They virtually work with all cannabis strains and growing conditions.
- Top 5 Best Fertilizers for Growing Cannabis
- Things to Consider When Buying Fertilizer for Growing Cannabis
- Frequently Asked Questions – FAQs
- What is the Importance of N-P-K Ratio?
- What are the Benefits of Organic fertilizers?
- Are Chemical Fertilizers Environmental Friendly?
- Can Nonorganic Fertilizers Cause Cancer?
- What are Slow-Release Fertilizers?
- What is Quick-Release Fertilizer?
- What is the difference between Complete and Balanced Fertilizers?
- What is a Combination of Fertilizer?
Top 5 Best Fertilizers for Growing Cannabis
#1 Osmocote Smart Release Plant Food
The Osmocote Smart Release Plant Food is a balanced formula that promotes strong root development and consistent top growth.
The granules in the formula are coated with a distinctive resin that helps to control the release of nutrients over a longer period. It releases nutrients slowly for up to four months.
The fertilizer comes with simple, easy to follow instructions for indoor or outdoor plants. The instructions are in English as well as Spanish.
This plant food has a good n-p-k ratio of 15-9-12. This ratio is ideal for both existing and new cannabis plants.
What We Like:
- Contains all the three main nutrients cannabis need
- Slow-release action feeds up to four months
- Simple and easy to follow instructions for beginner growers
- Formulated for colorful blooms and flavorful vegetative growth
- Boosts strong root development and top growth
What We Didn’t Like:
- May arrive with a damaged container
#2 Miracle-Gro All Purpose Plant Food
Grow cannabis plants twice as big with the Miracle-Gro All Purpose Plant Food. It is the easiest way to grow bigger and more beautiful marijuana plants.
This all-purpose plant food starts feeding your marijuana plants instantly, and it is suitable for both indoor and outdoor use.
This plant food has wider coverage. You can feed roughly six hundred square foot with 1.5 pounds of Miracle-Gro.
The fertilizer analysis for this formulation is 24-8-16, which is safe for all your cannabis plants. You will need to feed your plants every seven to fourteen days.
What We Like:
- Quick-release action works instantly
- It is safe for all indoor and outdoor plants
- Comes with easy to follow application instructions
- Has a wider coverage area per gallon
- You can feed slow-growing plants less often
What We Didn’t Like:
- Does not last long enough
#3 JR Peters Classic Blossom Booster
The brand was established in 1947. They manufacture fertilizers for specialty growing. The JR Peters Classic Blossom Booster is the perfect choice for cannabis growing.
The plant food is rich in phosphorous. It is usable during transplanting because of its fast nutrient absorption, making it suitable for both indoor and outdoor weed plants.
The fertilizer analysis for this product is 10-30-20. This combination boosts the production of more flowers as well as brighter colors.
For excellent results, you should apply the booster every seven to fourteen days. Use the formula during bud set to increase the size as well as the number of blossoms.
What We Like:
- Fast nutrient absorption makes it usable during transplanting
- It feeds easily through leaves and roots
- Suitable for indoor as well as outdoor flowering plants
- Increases the size and number of blossoms
What We Didn’t Like:
- Nonorganic may lead to excessive application and harm your plants
#4 Fox Farm Liquid Nutrient Trio Soil Formula
Fox Farm is a decent, family-owned brand with a focus on producing high-quality plant food for both indoor and outdoor plants.
The Fox Farm Liquid Nutrient Trio Soil Formula comes in a complete bloom booster package with excellent ratings on Amazon.
This three in one formula is the perfect choice for boosting the flowering stage of your cannabis plants. You should expect bigger and colorful blossoms.
In order to obtain the best results, you are advised to use the formulas in sequence. You should start with grow big, then switch to tiger bloom and conclude with the big bloom.
What We Like:
- Grow Big formula gives your cannabis abundant green growth
- Tiger Bloom formula helps with budding
- Big Bloom formula increases nutrient cycling
- Three in one solution for guaranteed high yields
What We Didn’t Like:
- Cost of this three-pack is relatively high
#5 General Hydroponics Liquid Kool Bloom Fertilizer
The brand was established more than forty years ago. It is an innovative brand that uses the latest research as well as manufacturing process to enhance the growth of your plants.
This formula has a good price point and it is available in four sizes. The formula focusses on early transition phases from vegetative to flowering.
It boosts faster ripening and improves bloom density. You are advised to use this formula at the beginning of the reproductive cycle.
The fertilizer analysis for this product is 0-10-10 and its application depends on your normal watering schedule.
What We Like:
- Contains stress-reducing vitamins
- Boosts faster ripening
- Improves bloom density
- No burning issues only vibrant flowering
What We Didn’t Like:
- Not suitable for large scale application
Things to Consider When Buying Fertilizer for Growing Cannabis
Fertilizers come in many forms as well as different formulas. Therefore, you must be keen when selecting a fertilizer for your cannabis plants.
Understanding Fertilizer Numbers (N-P-K)
Nitrogen, phosphorus, and potassium are the essential nutrients that your cannabis plants can obtain from the soil.
These nutrients are so important for marijuana productivity. So, you may have to add these nutrients to your growing medium through fertilizers.
N-P-K (Nitrogen-Phosphorus-Potassium) is the fertilizer ratio. This refers to the relative proportion of the major nutrients to one another.
There’re several ratios from which to choose. These choices are based on a soil test. Routine soil or growing medium tests will show if any of the major nutrients are lacking.
You can supply nutrients to your cannabis individually from several fertilizer sources or in combination with other types of nutrients.
For example, when potassium and phosphorus are plenty in the growing medium/soil, a fertilizer with a ratio of around 3-1-2 should be sufficient.
Three parts nitrogen to one part phosphorus to two parts potassium is frequently enough during your cannabis growth cycle.
An example is 15-9-12. This ratio tells you that 15% of the formulation is nitrogen, 9% is phosphorus, and 12% potassium.
You may add other nutrient elements or combine them with nitrogen, potassium, and phosphorus as needed.
Organic vs. Inorganic Fertilizers
You can choose either organic or inorganic fertilizer for growing cannabis.
This type of fertilizer builds up the growing medium and provides your marijuana plants with nutrition.
Organic fertilizers are usually obtained from organic materials, including animal, mineral and plant sources. Not to mention that they have to occur naturally.
Organic manures vary depending on the nutrient needs of your marijuana plants. In most cases, organic manures are made up of a single ingredient.
The ingredient and nutritional value of organic manures may not provide you with an immediate solution when compared to nonorganic manures.
What organic fertilizers do best is improve the fertility of your growing medium and enhance the aeration, drainage, and texture of your grow medium.
Inorganic fertilizers are mainly composed of artificial ingredients. They are usually formulated from synthetic compounds or mined from mineral deposits.
There are several types of nonorganic fertilizers on the market, including:
- Specially formulated
Which One Should You Choose?
So, what’s the difference between the two? Organic manures feed your plants while building the growing medium/soil.
Repeated use of nonorganic fertilizers, which usually provide only the three macronutrients, can deplete soils while harming microorganisms that keep your soil alive.
Organic manures provide secondary nutrients, such as calcium, sulfur, magnesium, boron, manganese, zinc, iron, and copper.
Using natural organic manures in combination with soil amendments, such as compost (which contains lots of organic materials) keep the soil alive.
Resorting only to nonorganic chemical fertilizers may result in compacted soil that is lifeless and unable to hold water and nutrients. So, choose your fertilizers wisely.
Dry vs. Liquid
Dry manures are available as slow-release pellets or granules. Generally, dry composts are integrated into granules.
Dry manure blends can be formulated by mixing different granular manure of known ratios, such as 0-0-60, 18-46-0, or 46-0-0.
If you have access to blended dry fertilizer, you can fine-tune your cannabis plants fertility. This will potentially enhance growth efficiency.
Liquid composts are liquid powders or concentrate that you need to dissolve in a liquid before you can apply them to your growing medium or soil.
These manures are normally incorporated with a dye that is meant to help you distinguish one product from another. Liquid concentrates are usually rich in nitrogen.
They are applied by two methods: foliar and ground application. Foliar application is a good way to supply trace elements to your cannabis plants.
You simply need to add the ideal concentrate to your normal spray, so long as the ingredients are compatible. You can use a foliar application if you suspect a deficiency of nutrients.
The second way of applying liquid fertilizers is through the ground application. This method allows you to place nutrients in a dilute form directly in the root zone of your plants.
Nitrogen and potassium are commonly used in ground application since they are easily dissolved. Many phosphate-supplying manures are relatively insoluble.
Now that you have an understanding of how to choose a good quality fertilizer for growing cannabis. It is time you learned how to read the labels.
When shopping for manures for growing marijuana, spend a significant amount of time reading and understanding the labels.
To begin with, all fertilizer packages you come across should display three numbers (N-P-K). As we learned earlier, these numbers refer to nitrogen, phosphorus and potassium content.
Each number stands for the percentage of the package made up of the available form of each nutrient by weight.
Natural organic fertilizers have three main ingredients:
1 – Plant materials
These ingredients are normally obtained from plants. A few examples are kelp meal, alfalfa, and corn gluten meal.
2 – Manure materials
You may also come across several manure materials, including worm casting, bat guano, cricket manure, and pelletized poultry manure to mention a few.
3- Animal byproducts
These refer to byproducts of the food industry and may include crab, blood, feather, bone, and fish emulsion meals.
On the other hand, most nonorganic manures will have a guaranteed analysis label somewhere on the package.
The label may contain information on the available nitrogen, phosphate and soluble potash. You should also see the percentage of slow-release materials.
Proper interpretation of the labels will not only help you choose the ideal formulation for your cannabis but will enable you to avoid unscrupulous chemical formulations.
Frequently Asked Questions – FAQs
What is the Importance of N-P-K Ratio?
The nutrient ratio of the total fertilizer applied is important for cannabis growing in the short run, and grow medium/soil health in the long run.
What are the Benefits of Organic fertilizers?
Natural products promote rooting as well as lateral growth. They do an amazing job of improving nutrient and water retention.
Also, organic manures stabilize the root zone and build up microbes. They supply non-leaching nutrients and also add energy-rich diet to exhausted soils.
Are Chemical Fertilizers Environmental Friendly?
Excessive use of chemical composts is responsible for environmental pollution. The impacts on the environment are usually bad and may take a considerable amount of time to address.
Therefore, it is wise to use eco-friendly fertilizers while maintaining proper cannabis growth and yield.
Can Nonorganic Fertilizers Cause Cancer?
According to research, typical exposure to inorganic chemical fertilizers is not enough to potentially heighten your risk of cancer.
What are Slow-Release Fertilizers?
These are manures that contain a chemical compound of nutrients or whose physical state is such that the nutrient availability to plants is spread over time.
What is Quick-Release Fertilizer?
These fertilizers are most often dry granules that dissolve fast after being spread, providing a lot of nutrients to your cannabis plants in a short amount of time.
What is the difference between Complete and Balanced Fertilizers?
A complete fertilizer formulation usually contains all the three main nutrients (N-P-K), but they may not be in equal proportions.
A complete fertilizer can have 5-3-3 or 10-10-10 combinations. This type of product can be all-purpose manure or a specific formulation for a specific plant type.
On the other hand, a balanced fertilizer is simply a complete fertilizer but has equal proportions of all the three main ingredients. For example, a 5-5-5 or 10-10-10.
What is a Combination of Fertilizer?
This is a fertilizer that contains both quick and slow-release formulation. The combination may have granules that dissolve fast mixed with beads that release nutrients more slowly.
Your cannabis plants need nitrogen, phosphorus and potassium to prevail. The inclusion of these three elements guarantees a healthy and bigger yield.
But as you have read there are some factors to consider to choose the perfect formulation for your specific type of cannabis plants.
The ideal fertilizer choice is one that provides uniform growth throughout the grow cycle and not just short-lived success.
In other words, rather than surging rapidly for a few days or weeks after being fed, the marijuana plants grow at a steady pace the entire growing season.
Regardless of which formulation you choose, just make sure you don’t suffocate your cannabis plants with a specific nutrient. Instead, have a balanced N-P-K ratio.