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Best Fertilizer for Cannabis

Last Updated: March 23, 2023
Roy Stevens
Product Review by Roy Stevens

A bountiful harvest full of healthy big buds is the ultimate end goal for the many home cannabis growers. The three main elements of a successful grow room are light, water, and oxygen.

But the fertilizer, nutrients, and schedule you choose to use are just as important to the health of your cannabis plants as the above. That’s why we’ve put together this list of some of the most popular, highly rated, and best fertilizer for cannabis.

Whether growing in soil or hydroponically, the fertilizers we’ve included will boost cannabis flower production alongside increasing your overall yield.

The best fertilizer for cannabis is entirely dependent on your method of growing, but in most cases, you’ll want a fertilizer made from the most natural organic sources. You can also opt for a synthetic powdered or liquid fertilizer for ease of use and timings.

They can offer quick fixes to many deficiencies. Many synthetic fertilizers also come with ready-made schedules that are ideal for beginners.

That’s not to say there are no drawbacks to these kinds of fertilizers, as there are a few, such as chemical burns or even the death of your beloved cannabis plants, but used correctly they can produce some impressive results.

There are plenty of fantastic products that utilize different formulas and techniques. But before we dive into the products, it’s important that you understand what NPK stands for, which is Nitrogen, Phosphorus, and Potassium.

If a bottle shows 6-4-4;

  • 6 is the level of Nitrogen
  • 4 indicates the Phosphorus
  • 4 indicates the Potassium

Now that you understand the basics, keep reading to see who made our list for the best cannabis fertilizer!

Our Reviews

FoxFarm Water Soluble Plant Foods

The Fox Farm Water Soluble Plant Foods (pack of three 1lb canisters) is without doubt one of the best plant food packages available today.

Boasting three specifically designed and scientifically developed plant fertilizers; beastie blooms, cha-ching, and open sesame, this package will help you achieve optimal crop harvests.

From first bud development all the way through the plants’ lifecycle, these three individual fertilizers will work to develop and help promote specific growth needs (dependant on the plant’s growing stage at any given time).

So, for instance, users should begin using open sesame to promote early flowering, then move over to beastie blooms when the plant is mid-flowering and then change to cha-ching to produce essential oils and help develop heavy resins.

This clever sequential feeding scheme takes the worry and complexity out of growing and allows growers of all varieties and experiences to achieve optimal growing conditions with a minimum of fuss.

Easy to use and exceptionally well priced, this fertilizer delivery schedule has been created by experienced growers and will enable all users to achieve optimal plant growth.


  • Easy to use
  • Helpfully scheduled for specific growing cycles
  • Highly rated
  • Quality ingredients & brand


  • Requires extra flushing

Jacks Hydroponic 5-12-26 25lb bag of fertilizer

If you are looking for a trusted, well-designed, and versatile fertilizer, then Jacks Hydroponic 5-12-26 25lb bag of fertilizer could be just what you are looking for.

With a new and improved design on Jacks classic “Part A” formula, this redesigned blend is the perfect hydroponic base for all your growing needs.

Incredibly versatile, the fertilizer can be adapted to such a degree that with very few slight modifications, this fertilizer is capable of providing any combination of nutrients that you need.

With an excellent balance of macro, secondary, and micronutrients, this fertilizer is capable of delivering a specific and efficient selection of nutrients dependant on your specific growing needs.

This fertilizer is well-liked among growers and is normally recommended to be used in conjunction with the 15-0-0 calcium nitrate (Part B) as part of a two-part system.

Significantly less expensive compared to some liquid fertilizers, the 5-12-26 fertilizer is an effective, efficient, and cost-effective method of providing excellent nutrition to your plants.

Highly sought after and with a comparatively excellent price, the Jacks Hydroponic 5-12-26 25lb bag of fertilizer is an excellent choice for new or experienced growers alike.


  • Excellent nutritional efficiency
  • Great value for money
  • Improved product


  • None

GAIA Green 4-4-4 Organic All-Purpose Fertilizer

GAIA Green 4-4-4 Organic All-Purpose Fertilizer (2kg bag) is one of the most versatile and proficient fertilizers on the market today.

Capable of improving the growth of a wide variety of plants, flowers, and vegetables, this incredible all-purpose fertilizer even helps promote healthy growth in trees and lawns.

Amazingly easy to use and with longevity rarely seen in other fertilizers, this mixture provides valuable nutrient release over a longer period so that feeding plants can consume their much-needed nutrients all season long.

The GAIA Green 4-4-4 Organic All-Purpose Fertilizer is the only fertilizer on the market that combines fossilized carbon complex with glacial rock dust, thus releasing a scientifically developed nutrient hit that not only boosts growth but also helps promote overall soil health.

Used by farmers, landscape gardeners, and solo growers over the past decades, this highly adaptable fertilizer come with some amazing recommendations, and with its long list of growth-boosting attributes, it’s easy to see why.

Capable of improving both small and large gardens and available at a comparatively excellent price, the GAIA Green 4-4-4 Organic All-Purpose Fertilizer (2kg bag) is well worth trying.


  • Specially engineered long-lasting formula
  • Highly adaptable
  • Easy to use


  • Expensive shipping costs

Coast of Maine Organic Plant Food

For anyone looking to revitalize their crops and wanting an effective, fast-acting, nutrient-rich organic plant food, then the Coast of Maine Organic Plant Food could be just what you are looking for.

Made with alfalfa, kelp, worm castings, fish bone meal, feather meal, to name just a few, Coast of Maine Organic Plant Food massively increases organic matter in the soil and is an incredibly effective soil conditioner and builder.

Alfalfa is an important forage crop and a perennial flowering legume in the pea family that takes nitrogen from the air and holds it within nodules on its roots in a process called “nitrogen-fixing”.

When alfalfa is dehydrated and ground into a meal, it then becomes an amazingly effective fertilizer that boosts the organic matter within the soil, providing quicker, stronger, and healthier grows.

Perfect for revitalizing soil and improving crop yields, the Coast of Maine Organic Plant Food is also incredibly versatile and able to be used in gardening beds as fertilizer.

With an excellent price tag and amazingly easy to use, this is yet another Coast of Maine product that is both affordable and effective and well worth purchasing for any growers looking to improve crop yields.


  • Fast-acting
  • Easy to use
  • Scientifically engineered


  • None

Fox Farm Marine Cuisine Dry Fertilizer

If you are looking for an extremely powerful and nutrient potent fertilizer, the Fox Farm Marine Cuisine Dry Fertilizer could be just what you need.

The four-pound Marine Cuisine dry fertilizer is not just powerful either it has also been scientifically developed to cleverly release the correct nutrients in a time-released manner, meaning that plants receive a balanced, consistent feed all year long.

The benefits of providing a steady, consistent, and well-organized feed throughout the year are that it encourages the growth of microbe populations which are needed for optimal growing conditions.

Able to be used on trees, shrubs, acid-loving plants and is considered to be perfect for growing vegetables by many experienced growers.

Containing specific ocean bi-products and low salt plant nutrients that are known to boost the growth of plants and cultivate a positive growth environment.

Additionally, the Marine Cuisine dry fertilizer naturally defends the soil against harmful nematodes, making it the perfect fertilizer for vegetable and flower gardens.

With a comparatively excellent price based on the long term benefits to growers and including a fantastic one-year guarantee, the Fox Farm FX14016 Marine Cuisine Dry Fertilizer is an ideal purchase for experienced gardeners or beginners.


  • Easy to use
  • Great price
  • Long term feeding plan


  • Not for use in organic crop or food production

Fox Farms Happy Frog Organic All-Purpose Fertilizer

For anyone looking to begin their journey into gardening and looking for an excellent, easy to use, all-purpose fertilizer, then look no further than Happy Frog Organic All-Purpose Fertilizer.

Using a scientifically developed mixture of the best fertilizers, soil, and microbes to assist growers in delivering optimal nutrition for your plants.

Additionally, mycorrhizal fungi are included in the powerful blend, and this helps improve root efficiency, which has a corresponding positive impact on water absorption and nutrient uptake.

Developed specifically to help improve container gardening, including perennial flower gardens, vegetable gardens, and all ornamental plantings.

Reviewed and listed by the Organic Materials Review Institute and containing only registered fertilizing materials approved by the California Department of Food and Agriculture, this fertilizer is an excellent product for all growers, especially those just starting their growing journey.

Exceptionally well priced and affordable for most growers budgets, the Fox Farms Happy Frog Organic All-Purpose Fertilizer is a great product that can help get you growing.


  • Excellent nutrient content
  • OMRI listed
  • Easy to use


  • More specialized fertilizers are available

FoxFarm Happy Frog Jump Start Organic Fertilizer

The FoxFarm Happy Frog Jump Start Organic Fertilizer is the perfect fertilizer for use on repotted container plants or transplanted seedlings.

The specially formulated blend of fertilizers supplies the perfect amount of both calcium and phosphorus to your growing plants, two elements that are integral to develop strong, healthy, and well-developed plants.

Calcium is the element that helps build stronger cell walls, and this, in turn, helps the plants become more disease resistant.

The FoxFarm Happy Frog Jump Start Fertilizer also includes mycorrhizal fungi, which helps increase root efficiency and massively improves nutrient uptake, making the plant stronger and healthier.

This fertilizer is perfect for those growers who have just started on their plant growing journey and are looking for a simple, effective, and easy-to-use fertilizer to help grow their first seeds.

As with all Fox Farm products, this fertilizer is competitively priced and is a great jumping-off point for anyone interested in growing and not wanting to trawl through hundreds of different fertilizers to find their initial one.

With glowing reviews, a well-developed effective fertilizer blend, and a great price, the FoxFarm Happy Frog Jump Start Fertilizer is one of the best fertilizers for beginners on the market.


  • Easy to use
  • Excellent for beginners
  • Great price


  • None

General Hydroponics Flora Grow, Bloom, Micro

General Hydroponics Flora Grow, Bloom, Micro Combo Fertilizer Set, 1 Quart contains primary, secondary and micronutrients for enhanced yields and better crop quality.

This pack-of-3 allows users to adjust the mixtures to suit the needs of their crops. FloraBloom stimulates flower and fruit development while enhancing the aroma, flavor and essential oils in soil cultivated and hydroponic plants.

The General Hydroponics Flora Grow, Bloom, Micro Combo Fertilizer set formula contains highly purified concentrates for maximum solubility, superior formulation and reliability.

This formula is PH balances for ease of use and is the choice for NASA and Antarctic research scientists!

The Flora Grow, Bloom and Micro provide high phosphorous, potassium, magnesium and sulfur. The building blocks approach also provides nitrogen and calcium.


  • Mixture is adjustable
  • Builds strong roots
  • Contains highly purified concentrates
  • Suitable for beginners
  • Great value for money


  • Be careful, it’s easy to burn the plants if you don’t follow the instructions

Grow Girls Grow Organic Fertilizer

Designed for all types of cannabis grow set-ups, Grow girls Grow Organic Fertilizer is the ideal solution for your cannabis plants when in the vegetative stage. Add this fertilizer to your growing regime if you’re looking to grow healthy, strong, big buds!

Featuring a 8-4-6 NPK mix, with well over 50 micronutrients including humic, fulvic acid, kelp calcium, magnesium, and an array of mineral compounds, vitamins, enzymes, and more, the Grow girls Grow Fertilizer is ideal for beginners and pro’s.

Add Grow Girls Grow to your water schedule, then sit back and wait for your cannabis plants to explode! This concentrated powder is perfect for soil, coco, and hydroponic grow set-ups.


  • Perfect for veg stage plants
  • Can be used in all mediums including Soil, Coco, Hydroponics setups
  • Top rated


  • Pricey

Jacks 15-0-0 Calcium Nitrate 25lb Fertilizer (Part B)

Jacks 15-0-0 Calcium Nitrate 25lb Fertilizer (Part B) is an excellent accompaniment to Jacks new versatile Hydroponic 5-12-26 25lb bag of fertilizer.

Part of the new, two-part system that Jack recommends to achieve the best growing results, the Calcium Nitrate allows growers to raise media pH and reduce ammonium, sodium, and high micronutrient levels.

A high quality and superb, soluble form of calcium that is easily absorbed by plant roots and helps supplement the plants’ calcium and nitrate-nitrogen levels.

Jack’s new and improved two-part fertilizer system is extremely versatile and allows growers to customize their hydroponic fertilizer to beat suit their growing needs.

Incredibly adaptable and working in conjunction with the Hydroponic 5-12-26 25lb bag of fertilizer, Jacks have developed a near-perfect fertilizer nutrient distribution system.

With the emphasis on the quality of the fertilizer being so paramount and the recommendations to use with other Jacks products, some growers may be put off by the potential high expenditure.

However, if you are looking for a thorough, efficient, and effective fertilizer system, then Jacks 15-0-0 Calcium Nitrate 25lb Fertilizer (Part B) should definitely be top of your list.


  • High quality
  • Easy to use
  • Time-efficient


  • Pricey

Mother Earth Farmer's Market All Purpose Mix 4-5-4 Granular Fertilizer

Mother Earth Farmer’s Market All Purpose Mix 4-5-4 Granular Fertilizer is without doubt one of the best all-purpose fertilizers available on the market today.

Able to be used on everything from delicate roses to wilting trees, the specially designed blend of nutrients in the fertilizer means that it provides optimal nutrition regardless of whether you are feeding your lawn, flowers or shrubs.

Developed specifically to include all the primary nutrients that plants require, this all-purpose fertilizer not only feeds the plant but encourages cellular strength and builds up the plants resistance to disease.

With the Mother Earth Farmer’s Market All-Purpose Mix, there is no need to constantly change to different fertilizer mixes dependant on the plant’s stage in its lifecycle.

Rather, this all-purpose fertilizer can continue to be used throughout the plant’s life, saving you untold amounts of time, effort, and money.

In addition to the efficiency savings mentioned above, you will also be purchasing this fertilizer at an exceptional price in the first instance as well.

So with an excellent price, a phenomenal nutritional blend, and some pretty rave reviews, it’s easy to see why Mother Earth Farmer’s Market All Purpose Mix 4-5-4 Granular Fertilizer is flying off the shelves.


  • Able to be used through plant life
  • Cost-effective
  • Easy to use


  • More specifically designed alternatives available

Mother Earth LiquiCraft Bloom Plus LiquiCraft Grow Fertilizer

Mother Earth LiquiCraft Grow 4-3-3 Liquid Fertilizer is yet another impressive premium fertilizer product from the incredible guys at Mother Earth.

Scientifically developed to provide the best nutrition possible at the times when you most need it, this fertilizer works best on plants in their vegetive state.

Amazingly easy to use, the LiquiCraft Fertilizer just requires two teaspoons to be added into a gallon of watering, and just like that, you have a versatile, nutritious, and powerful fertilizer ready to use.

The specifically designed mixture helps encourage fast growth in both leaf and branch and is doubly effective during the crucial vegetive stage when plants need a targeted, nutritional boost.

Focussing on both the primary and secondary nutrients that your plants need, Mother Earths Liquicraft gives you the security to know that your plants aren’t missing out on critical nutrients when they need them most.

This mixture is perfect for shrubs, herbs, vegetables, and annual flower crops and is available in multiple sizes to suit your fertilizing needs.

Perfect for growers who have just started a new grow and are looking to add a fertilizer with substantial nutritional value and coming with a very competitive price tag, Mother Earth’s LiquiCraft Grow 4-3-3 Liquid Fertilizer ‘is an excellent investment.

A natural linear successor to LiquiCraft Grow and best used in conjunction with it, Mother Earth’s LiquiCraft Bloom 2-4-4 Liquid Fertilizer picks up the fertilizing baton and takes supplementing your plant’s nutrients to the next level.

When your plants begin fruiting or blooming, it is important to give them the nutrients that they require for optimal growth during this phase; these nutrients are inevitably different from the ones needed during the previous phase as the plant’s needs continue to change.

Mother Earth’s LiquiCraft Bloom 2-4-4 Liquid Fertilizer builds upon the nutritional platform created by the LiquiCraft Grow, and goes one step further, and provides specific nutrients designed to increase and optimize blooming.

Syncing perfectly with not just LiquiCraft Grow but also the whole Mother Earth product range, it is important to remember that LiquiCraft Bloom is the second part of a two-part system and that you will achieve the best results by using the whole range as this then caters for all your plant’s needs.

With an excellent price and some phenomenal results (especially when used with LiquiCraft Grow), this is a fertilizer that will help you get your buds big.


  • Strengthens young plants
  • Premium liquid foundational fertilizer
  • Fast-acting
  • Part of a two-part growing system
  • Helps optimize plant growth during bloom
  • Easy to use


  • Pricey

Mother Earth's Root Down Plant Starter Mix 3-6-3 Granular Plant Fertilizer

Mother Earth’s Root Down Plant Starter Mix 3-6-3 Granular Plant Fertilizer is a fantastically versatile fertilizer that caters to a massive variety of growers needs.

The Starter Mix is able to be used in a number of different settings such as hydroponics, raised grows, in-ground as well as being developed to be used indoors and outdoors.

This versatility means that regardless of your experience level as a grower, then this Starter Mix will be perfect for you.

Whether you are just beginning your growing journey and need help with your homegrown fruit and vegetables, or whether you are a more experienced grower with a more extensive hydroponic setup, the Starter Mix helps meet all growing needs.

Scientifically developed to encourage and improve plant growth as well as strengthening and increasing root development in young plants and seedlings, the Starter Mix provides the perfect blend of nutrients to grow healthy, strong, vivacious plants.

Competitively priced and recently garnering rave reviews from growers, Mother Earth’s Root Down Plant Starter Mix 3-6-3 Granular Plant Fertilizer represents excellent value for money and provides an excellent platform to start your growing journey or some much-needed assistance to boost your plants for more experienced growers.


  • Perfect for young plants and seedlings
  • Encourages vigorous growth
  • Versatile


  • Bit of an odor

What Should my Plants Nutrients Include?

There are few things to consider before adding nutrients to your schedule. The secret to choosing the right nutrients is understanding the requirements of your cannabis plants and having an awareness of how they absorb and utilize nutrients. Once you have this knowledge, you can make a decision about which nutrients to buy without wasting your money and damaging your plants

What Are The Best Nutrients for Cannabis Grown In Soil?

Soil differs from hydroponic soilless blends because it contains organic matter such as compost, manure, humus, and worm castings.

Organic matter contains a lot of micro and macronutrients which need to be processed by microbes and fungi that live in the soil in order to be useful to your cannabis plant.

Organic nutrients and fertilizers contain fewer nutrients that are soluble with the elements that have benefits for organisms naturally in the soil. Therefore, If you want to grow your plants in soil, you should use organic nutrients and fertilizers.

Organic fertilizers have plenty of essential nutrients such as nitrogen, phosphorus, potassium, sulfur, magnesium, and calcium. Some of the blends contain the ideal mix of nutrients for your convenience.

What’s the Difference Growing Cannabis using Hydroponics?

If you choose to use hydroponics to grow your cannabis, you will need specific nutrients because you won’t be using soil.

Most nutrients that are sold for growing marijuana plants are those for hydroponic techniques. They’re made using concentrated mineral salt and are often available in liquids but can also be sold in powder form.

There are two types of hydroponic growing;

  • Bloom solutions have high phosphorus level to encourage flower development
  • Grow solution has a high nitrogen level to aid vegetative growth.

Adding too many nutrients can damage or even kill your plants, so it’s important that you take care during the application. It’s useful to be cautious and only apply 25% of the recommended amount, working up gradually to full strength.


Cannabis plants require the following micronutrients;

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

Your plants will only need a small amount of these elements, however, they’re beneficial to the plant’s overall health and growth.

How Can I Achieve Healthy Cannabis Plants?

Cannabis plants need macronutrients that come from water, air, and some from the soil.

Oxygen, Hydrogen, and Carbon come from the water and air. Phosphorus, Nitrogen, Potassium, Calcium, Magnesium, and Sulfur come from the soil.

As we mentioned in the introduction, when you purchase fertilizer, you’ll find three numbers on the packaging. These numbers show the levels of nitrogen, phosphorus, and potassium in the mixture.

Cannabis Plants And Feeding Problems

You should be cautious when you’re growing cannabis because too many nutrients could damage your plants. If you’re in any doubt, only add nutrients to the water every alternate watering.

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

If your feeding problems persist, flush pure water through the soil for several days before resuming with half doses of the nutrient mix.

It’s normal to be cautious when you’re growing cannabis plants for the first time. If you follow our tips and tricks, your plants should be healthy and meet your expectations!


When it comes to choosing the best fertilizer for cannabis, there are many brands to consider. But before you make a decision, remember to look at all the reviews and research as much as you can. What nutrients you choose to use can ultimately be the success or failure of your cannabis crop.

Consider every aspect of your set-up, from the cannabis strain you’re choosing to the equipment, and grow system you utilize. Growing hydroponically will require a completely different fertilizer to growing with soil, as would growing indoors under LEDs or growing outdoors.

Ultimately, the best fertilizer for cannabis is the one that works best for your situation and grow set-up. Giving your cannabis plants the right nutrients and fertilizer is a delicate balance to get right, but once you succeed, you’ll achieve a healthy and bountiful harvest.

Our top pick out of the fertilizer we’ve reviewed today is Jacks Hydroponic 5-12-26 25lb bag of fertilizer (part A). The highly rated, quality fertilizer is pricey, but most cultivators would say the results far outweigh the price tag.

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