Top 10 Best Bud Food & Bloom Booster Fertilizers

The most effective flowering fertilizers for big buds (best bloom boosters). Get the high yields & save money by knowing what they’re made of. Best nutrients for flowering cannabis.

best fertilizer for weed big buds-top

Organic Fertilizers

Organic fertilizers are made of natural ingredients. The highest concentration of nutrients come from mineral powders, manures & animal parts. Seaweed and molasses are also used in organic bud foods to promote beneficial bacteria and aide in plant growth processes. The presence of mycorrhizal fungi can help plants absorb organic nutrients like Phosphorus easier.



Overview: A lot of ‘secret’ bud enhancers are simply kelp derivative and soluble potash. Seaweed-derived products have been widely used due to the presence of a number of plant growth-stimulating compounds. Save money on expensive liquid formulas by using kelp meal like Maxicrop, which is harvested Norwegian kelp (Ascophyllum nodosum).


How it benefits flowering: NPK 0-0-17. A natural source of potassium and powerful biostimulants, Maxicrop contains more than 70 minerals, micronutrients, amino acids and vitamins to help with bigger more prolific blooms. Studies have shown that Maxicrop application increased plant root growth by 53-63%. It is also used for cloning & transplanting solutions due to the presence of vitamin B12.


Application: Dissolve 3 tbsp of Maxicrop powder per gallon of water, suitable for all cultivation set-ups. Don’t spray buds it will stick.





Happy Frog Bulb Food

foxfarm happy frog bulb food

Overview: FoxFarm’s Happy Frog dry fertilizer is a mix of granular organic bud food ingredients such as bone meal, bat guano, and kelp meal. It’s alive with beneficial soil microbes and mycorrhizal fungi inoculant that expand root development enabling plants to feed more aggressively.


How it benefits flowering: NPK 3-8-8. Happy Frog Bulb Food adds humic acid (a natural byproduct of organic matter decomposition) as an organic chelating agent to help release the long-term nutrients contained in this fertilizer for plant absorption.


Application: Follow dosage instructions on label for plant size. It can be mixed into potting mix before final transplant, probed into the root system, or layered onto the topsoil.





BioThrive Bloom

biothrive bloom hydroponic vegan fertilizer

Overview: Vegan plant food. BioThrive is loaded with a myriad of organic substances including alfalfa meal, cane sugar, copper sulphate, glacial rock powder, iron sulphate, kieserite, manganese sulphate, molasses, plant extracts, potassium sulphate, rock phosphate, sodium borate, sodium molybdenate, soybean meal and zinc phosphate.


How it benefits flowering: NPK 2-4-4. Bio Thrive contains the essential nutrients with a hearty dose of carbohydrates (sugars) known to stimulate beneficial microbial activity.


Application: Dilute 4 tsp. of BioThrive per gallon of water. This liquid fertilizer is convenient for all types of growing – from hydroponics to in-the-ground soil application.





Jobe’s Organics Bulb Food Fertilizer

jobes organics bulb food

Overview: Jobes Organics Bulb Fertilizer granular plant food is made from an all-natural blend of bone meal, poultry manure, sulfate of potash plus the addition of beneficial bacteria and Endomycorrizae.


How it benefits flowering:  NPK 3-5-4. The Archaea is a unique beneficial micro-organism which plays a role in soil carbon and nitrogen turnover. Calcium and Magnesium help strengthen plants and promote photosynthesis. Combined they make an effective bud hardener


Application: Mix in 1 1/2 cups of fertilizer granuals per each 10′ of soil area for transplants or add 1 1/2 tbsp. per each 4″ of area for seedlings.





Dr. Earth Organic Bud & Bloom Fertilizer

dr earth organic bud bloom fertilizer

Overview: Dr. Earth Organic Bud & Bloom fertilizer is made from a blend of fish bone meal, alfalfa meal, feather meal, soft rock phosphate and mined potassium sulfate. Includes beneficial soil microbes and Mycorrhizae.


How it benefits flowering: NPK 3-9-4. This well-rounded dry fertilizer is suitable as a stand-alone flowering supplement.


Application: Use ~2 cups per inch of trunk diameter. Follow the label directions for detailed guidelines. Mix it into soil medium during transplants, apply as a probe around the roots or use as a topdress.




Synthetic Fertilizers

Synthetic fertilizers are made of various elemental compounds, mostly derived from the chemical chelation of minerals. The chelation process helps transform these minerals into nutrients that are easily absorbed by plants.

Synthetic nutrients work best in hydroponics, aeroponics, or in an easy-flush, low-retention potting mix like 50% perlite, 50% vermiculite.


Jack’s Classic Blossom Booster

jacks classic blossom-booster fertilizer

Overview:  J R Peters Jack’s Classic Blossom Booster provides the essential NPK nutrients for flowering plants, plus micronutrients in an inexpensive water-soluble powder.


How it benefits flowering: NPK 10-30-20. This classic 1:3:2 nutrient ratio has proven to be the standard for blossom enhancers. A lot of hydro growers are ditching the expensive bottled nutrients and switching over to Jack’s to save money.


Application: One tablespoon of powder per gallon of water. Can be used in any grow set-up including hydroponics & aeroponics.





Flower Fuel

flower fuel big-bud fertilizer

Overview: Flower Fuel is a heavy-duty, high PK blossom booster that contains over 40 ingredients: nutrients, vitamins, hormones, amino acids, essential organic components, and every single micro and trace element.


How it benefits flowering: NPK 0-39-25. This type of high PK bloom booster is used throughout flowering to promote loads of resinous bud sites that develop into big buds right down-to the-stem.


Application: 1/4 teaspoon per gallon of water. Their 250g container treats 200 gallons of water. Suitable for any soil, coco, hydroponic or aeroponic system.





Grow More Hawaiian Bud

grow more hawaiin bud-nutrients

Overview: A hard-hitting nutrient ‘boom!’ for plants, Grow More Hawaiian Bud is packed with very high amounts of phosphorus, high amounts of potassium, a little nitrogen and chelated micronutrients.


How it benefits flowering: NPK 5-50-17. Potent PK fertilizers like Hawaiian Bud will help plants stack up heavily with multiple bud sites. This can contribute to heavy yielding big bud harvests when applied correctly.


Application: Suggested use varies at 1/4-1 teaspoon per gallon of water. Be careful of burning plants by overfeeding.





FoxFarm’s Liquid Bloom Trio

foxfarm liquid nutrient trio for flowering grow big buds

Overview: The liquid bloom trio by Foxfarm are not completely organic. While Big Bloom is organic, Tiger Bloom and Grow Big are not. A look at the label ingredients reveals the added synthetic nitrates and phosphates.


How it benefits flowering: These fertilizers are softer in comparison to other chemical fertilizers (no crazy-high levels of P) containing readily-available nutrients combined with organic ingredients and active microbes. These three bottles are sold together in their fully-balanced bud flowering formula.


Application: 2-4 teaspoons per gallon of water. FoxFarm liquid fertilizers can be used in soils, pots, hydroponics & aeroponics.





Osmocote Smart-Release Plant Food

osmocote slow-release plant-food flower

Overview: Most inorganic fertilizers are readily-available, meaning that they do not last long after application and need to be reapplied regularly for best results. Osmocote Smart-Release Plant Food is a slow-release granule fertilizer that feeds plants for up to 4 months.


How it benefits flowering: NPK 14-14-14 controlled release. A balanced high-nutrient long-term synthetic fertilizer. Osmocote was most popular during the 90’s and is a tried-and-true for old-school guerrilla growers.


Application: For 4″ plants 1 teaspoon worked into topsoil or mixed into potting medium.





bloom booster faq section

What Nutrients Does Cannabis Need to Grow?

Nutrients are used like food by plants. Cannabis requires large amounts of mineral nutrients to compose its leaves and dense flowers. The best nutrients for cannabis are in fact the nutrients which are used by the plant to support growth.

  • Well-fed cannabis plants are green and healthy, which can lead to increased flower production and higher yields of bigger buds. Well-fed plants have a stronger immunity to disease than underfed plants.
  • Underfed cannabis plants are often slow to grow, stunted, yellowing and frail. The buds develop sparsely and produce a lower quality and yield than well-fed plants. Underfed plants have a weak immune system due to lack of nutrients.

cannabis-plant what nutrients required to grow

There are six major nutrients that cannabis plants require to grow – three of which are obtained from the air and water:

  • Carbon Dioxide (CO2) – Plants simply absorb CO2 from the air, combining it with water and light, to make carbohydrates – a process more commonly known as photosynthesis.
  • Hydrogen (H) – Hydrogen is a part of water (H2O). As plants absorb water, they split the water molecules into hydrogen and oxygen using the energy from the sun.
  • Oxygen (O) – Along with what has been described above, plants consume oxygen through their pores – even at night. This is what’s called respiration. Respiration combines oxygen and the food created during photosynthesis to produce usable energy for plants.

The other three nutrients are Nitrogen (N), Potassium (P) and Phosphorus (K). These nutrients are mostly obtained though a plant’s roots, but can also be absorbed through tissue (i.e. foliar feeding).

Major Nutrients (N-P-K)

What are the three numbers labeled on fertilizers?

NPK (short for Nitrogen, Phosphorus and Potassium) are the major nutrients that plants absorb though their roots, or vascular tissue. NPK are the three numbers you see labeled on the front of commercial fertilizers.


npk fertilizer nutrients bag

The numbers represent the percentage of a nutrient a fertilizer is made of. So for example, a 50-kg bag of 12-24-12 fertilizer would be composed of 12% N, 24% P, and 12% K. To figure out how much K that is you can multiply the weight by the percentage: 50 kg x 0.12 = 6 kg of K.


nitrogen n

Nitrogen (N)

  • Nitrogen (a gas) is a major component of amino acids (the building blocks of proteins) and chlorophyll (the energy substance made by plants through photosynthesis). Nitrogen is the most utilized nutrient of a plant’s life-cycle, especially during its early stages of growth.
  • Organic sources of N are plant litter, compost, manures, blood meal, feather meal, ect.
  • Synthetic derivatives of N include formulations of urea and ammonium nitrates.

Using Nitrogen for flowering cannabis:

High nitrogen fertilizers have a pronounced effect on cannabis plants, often triggering vertical growth. This is why only moderate levels of nitrogen are applied to blooming cannabis plants in order to keep their buds hard, dense and compact. Cannabis fertilizers with a high ratio of nitrogen are usually “veg” nutrients, intended for the early stages of growth.

phosphorus p

Phosphorus (P)

  • Phosphorus (a mineral element) is a component of the complex nucleic acid structure of plants, which regulates protein synthesis. It is important in cell division and development of new tissue, also associated with complex energy transformations in the plant. Phosphorus lets plants use the energy harnessed by photosynthesis to drive its metabolism.
  • Organic sources of P include soft rock phosphate, bat guano, steamed bone meal, fish bone meal, and crushed granite.
  • Synthetic derivatives of P are made by treating rock phosphate with either sulfuric acid or phosphorus acid.

Using Phosphorus for flowering cannabis:

High phosphorus availability to plants can lead to additional flower (bud) sites and a healthy root system. The most critical time for cannabis plants to utilize phosphorus is during the beginning of their blooming process (first white hairs), as this is when a big energy change happens in the plant. Cannabis fertilizers with a high ratio of phosphorus are often used as “flowering” nutrients, meant for the mid-late stages of growth.

potassium k

Potassium (K)

  • Potassium (a mineral element) triggers the activation of different growth-related enzymes important in many chemical processes taking place during flower production. It also regulates the opening and closing of stomata (pores) during photosynthesis, in part controlling CO2 uptake. Potassium is attributed to playing a major part in the absorption and movement of water, nutrients, and carbohydrates in plant tissue.
  • Organic sources of K include soluble potash (ashes), manures, compost, molasses and kelp meal.
  • Commercially-used K like muriate of potash and sulphate of potash are salts that make up part of ocean saline deposits.

Using Potassium for flowering cannabis:

Potassium is a catalyst for carbohydrate metabolism, so when you want your marijuana plants to pack on the carbs, high levels of K are important. Potassium rivals nitrogen as the nutrient absorbed in greatest amounts by plants. It’s best to increase K levels during the midst a plant’s flowering cycle, healthy amounts of potassium will lead to hard, thick and heavy bud yields. Cannabis fertilizers containing a high ratio of potassium are usually “flowering” nutrients, used in the mid-late growth stages.

Minor and Micro-Nutrients

minor and micronutrients plants periodic table chart

Minor and micro-nutrients are essential for healthy plant growth, just used in smaller amounts by plants hence the name.

There are three nutrients classified as minor nutrients. These are:

  • Calcium (Ca) – has a regulating effect in the cells and contributes to the stability of the plant, important in the development of cell walls.
  • Magnesium (Mg) – is a building block of chlorophyll, essential to the process of photosynthesis. Without magnesium, plants cannot process sunlight.
  • Sulfur (S) – is used in the formation of amino acids, proteins, and oils. Sulfur helps develop and activate different vitamins and enzymes.

Seven elements are needed in tiny amounts, these are dubbed micronutrients.

  • These include boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), nickel (Ni) and chloride (Cl).
  • Being deficient in any of these micronutrients can impair growth.

What are Effective Flowering Fertilizers?

best nutrients for flowering cannabis buds

The best bloom boosters, bud foods and flower fertilizers are terms for the right nutrient additives meant to be used when a plant is producing flowers (buds). These nutrients are available to plants in the form of organic material (organic fertilizers) or are derived though chemistry procedures (synthetic fertilizers).

What do the best bloom fertilizers have in common?

  • High proportions of Phosphorus (P) and Potassium (K), to maximize bud formation & growth-related enzymes in the plant.
  • Low proportions of Nitrogen (N), to prevent bud stretching.
  • Calcium (Ca) and Magnesium (Mg) are utilized to aid in dense flower clustering, along with other minor nutrients, micronutrients, and trace minerals.

npk ratio cannabis

Cannabis Fertilizer Ratio

NPK ratio recommendations for crops are typically provided to farmers via a university extension office. As a rule of thumb, cannabis may follow similar NPK guidelines as those given for tomatoes.

A high-N “starter fertilizer” is provided during the early growth (veg cycle) to promote vigorous growth while a high-PK “bloom fertilizer” is given during the later growth (flowering cycle) to support budding.

Cannabis growers tend to ween off nitrogen as the plant gets closer to harvest time. For example, a low-N, high-PK fertilizer near 1:3:2 ratio (2-6-4, 4-12-6, etc.) will be used for early and mid flowering cycle while a PK-only fertilizer (0:1:1 or 0:3:2 NPK ratio) is applied towards the end of flowering.

organic vs chemical fertilizer

Organic vs. Synthetic Nutrients

  • Organic cannabis fertilizers contain both readily available and long-term nutrient sources. A thriving microbial ecosystem will help plants access these nutrients faster.
  • Synthetic cannabis fertilizers are readily-available nutrients (with the exception of controlled-release fertilizer). These contain chemically chelated nutrients for immediate absorption by plants.

cannabis fertilizer burn

Cannabis Fertilizer Burn

Overapplication of fertilizer nutrients on cannabis plants can lead to “fertilizer burn” or “tipburn” – a desiccation of plant tissues seen as a leaf scorching, due to the osmotic stress caused by over fertilizing.

Avoid fertilizer burn by following the recommended application guidelines on fertilizer product labels. Cannabis plants that show signs of fertilizer burn should be “flushed” with a long watering to rid excess nutrients from the root zone.

nutrient lockouts

Nutrient Lockouts

When applying high amounts of fertilizer it’s important to take into account the possibility of a nutrient lockout. This can occur from pH imbalance or excess nutrient buildup. Buildup often happens in mediums that can not be flushed clean of P, as this nutrient has a tendency to cling to other particles in soil.

When too much P is present in soil it binds up calcium, copper, iron, magnesium and zinc making these nutrients unusable. Excess P also has harmful effects on beneficial soil organisms such as mycorrhizal fungi.

Compost and Worm Castings as Fertilizer?

worm castings-vermicompost fertilizer-organic-bud-food

There are benefits to using organic matter in soil like increasing water and nutrient holding capacity of the soil, improving soil structure and promoting beneficial microbes.

Compost is often analyzed as a 1-1-1 dilutant fertilizer. However, all compost varies in composition. The nutrient profile of compost depends on what was used to make it.

Worm casting compost made with egg shells (calcium) and banana peels (potassium) are a great DIY organic bud food that you can make at home.

Best Fertilizer for Cannabis Buds Shortlist

MaxicropOrganic0-0-17VIEW PRICE ►
Happy Frog BulbOrganic3-8-8VIEW PRICE ►
Biothrive BloomOrganic2-4-4VIEW PRICE ►
Jobe’s Organics Bulb FoodOrganic3-5-4VIEW PRICE ►
Dr. Earth Organic Bud & BloomOrganic3-9-4VIEW PRICE ►
Jack’s Blossom BoosterSynthetic10-30-20VIEW PRICE ►
Flower FuelSynthetic0-39-25VIEW PRICE ►
Hawaiian BudSynthetic5-50-17VIEW PRICE ►
Liquid Bloom TrioMixedMixedVIEW PRICE ►
OsmocoteSynthetic14-14-14VIEW PRICE ►


Disclaimer: We do not promote or undertake in illegal activities. Refer to our Privacy Policy for more information.

21 thoughts on “Top 10 Best Bud Food & Bloom Booster Fertilizers”

    • I agree Dino, Personally a big fan of the Happy Frog fertilizers from Fox Farm, and good ol’ Maxicrop… Maxicrop, or Norwegian sea kelp is a great trace minerals fertilizer/supplement with a little bit of potassium as well. I have seen times personally where a cannabis plant is not growing with the optimum health and vigor, then simply maxicrop (sea kelp) was supplemented to the weed plant and in a matter of hours that plant’s color had changed to a deeper green and had visually gained vigor, eventually flowering and finishing up into some heavy yielding, big-budded chronic. Sometimes the small things may be overlooked in certain soils, adding sea kelp into your soil or onto your plant(foliar feeding) is a reliable way to ensure that hungry cannabis plants get the nutrients they need to grow big and yield hard.

    • Hi Dino, Many FoxFarm fertilizers ARE organic, such as the Happy Frog dry fertilizers, but others such as ‘Tiger Bloom’ and ‘Grow Big’ are non-organic – read above ^^

    • Hi Maxime, for a cheap buy, yes it’s a good dry fertilizer complete with all the best nutrients for cannabis during it’s flowering stage. However the size of the plant is also important. Larger plants need more nutrients so they can handle a few cups worth of it each.

  1. General Hydroponics and botanicare is now owned by Scotts Mircle Grow and they run tooo salty.

    Try House and Garden

    Humboldt Nutrients- especially the Humboldt Natural Grow/Bloom ( big boy stuff… the smell is overwhelming but the flowers stack so well)

    Canna always heavy yields.

    Technaflora, Roots Organics, FoxFarm , all great lines!!!!

  2. My Cannibis plants are in their flowering stage, what is the best food to give them right now? We are feeding them koolbloom 0-10-10 right now but there is no odor what so ever. I need your help please.

    • Kool bloom rocks just use the liquid and the dry stuff as prescibed. Remember that not all plants have that heavy marijuana smell. Also genetics play a part. Use bud candy and molasses throughout and up to about week 6 of bloom. Make sure you flush your plants well. Another thing is genetics, some plants may just be a dud it, happens. I have grown plants right next to each other and had one turn out rocket fule while the other just could not compare. Go figure??????

  3. My favorite is primordial solutions sea greens, really does the trick along with aloe extract (2 bucks on ebay) and kelp with fuvic and humic acid

  4. Does anybody source their own major, minor and micro micronutrients or make their own blend? It’s very economical to do it yourself.
    Here are a few of the materials we offer:
    Magnesium Chloride – Anhydrous and Hexahydrate
    Magnesium Sulfate – Anhydrous and Heptahydrate
    Potassium Sulfate
    Calcium Nitrate – Powder and Liquid


Leave a Comment