DIY PK Boost similar to HammerHead

Hammerhead by AN is a well-known PK boost, and this formulation comes pretty close, and uses only 3 ingredients (well actually 4 if you count water). You can make your own for a fraction of the cost of commercial PK boosting products.


  1. Potassium sulfate aka soluble potash = 65 grams
  2. Monopotassium Phosphate aka MKP= 100 grams
  3. Magnesium Sulphate aka epsom salt = 4 grams
  4. 1 quart of water

Add the soluble potash to your water first and let that dissolve, and then the epsom salts, and then add the MKP.

NOTE: always add first to your water, before adding the nutrients
Starting at 10 days into flowering add 1 ml per liter of water
At 3 weeks increase to 1.5 ml per liter of water
At 5 weeks increase to 2 ml per liter of water
Continue to water at the rate of 2 ml per liter of water until your final flush

When used in combination with MOAB or something similar, it is known to help create frosty giant dense buds. You can learn how to make your own MOAB here : DIY Bloom Enhancer and Ripening Agent (aka MOAB)

bring your base down by 50%
10 ml of Hammerhead
10 ml MOAB
5 gallons of water


I wonder if all your recipes could be combined into 1 thread and then stickied to the FAQ (or somthing). Just so they all come up at once as a make your own fertz section and nothing gets missed!

I’m going to have to try some of these!


Awesome recipe, wouldn’t happen to have a rough NPK numbers for this would you

1 Like

The NPK should be roughly 0-9-18


Dumb question, but any issues using this in hydroponics?

1 Like

not a dumb question - Application Rate: In nutrient reservoir mix 2.0 mL per liter of nutrient solution. Use from week two until flush of bloom cycle

1 Like

HammerHead is a discontinued product, but this is the spiel from when it was being sold:

Benefits and Features: The only PK booster with the right PK ratio; get bigger, better buds for the crops you grow Phosphorous and potassium both support floral production and ripening. However, the plants you grow use twice the amount of potassium as phosphorus during flowering. Research has shown that potassium is crucial for the synthesis of essential oils. Phosphorus is vital for the synthesis of secondary metabolites (terpenes, phenolics, cannabinoids). However, phosphorus is a catalyst in cells and hence is NOT consumed in this process. Thus, your plants need a lot of K and a certain amount of P - but not too much.

Avoids the risk of phosphorus toxicity: HammerHead’s 4:10 PK formulation provides plenty of phosphorus without creating phosphorus toxicity like other formulas do. Research shows that 13:14 PK bloom boosters often create phosphate toxicity. Some growers using 13:14 fertilizers have encountered occurrences of phosphate accumulation in leaves that result in toxicities to their plants; leaves become spotted with grey-green lesions that become brown, or leaves show tip-burning following the applications of these PK products. Excess phosphorus can also interfere with the uptake of other nutrients. Phosphate toxicity also results in harsh tasting buds. That’s why using 13-14 PK boosters harms our plants and often results in lesser yield rather than more. (The 13:14 ratio was traditionally used for soil growing and a lot of phosphorus would be leached out of the soil.) HammerHead’s PK formulation of 4:10 lowers the potential for phosphorustoxicity that results when growers aim to increase potassium levels for their blooming crops. HammerHead stimulates roots, making it easier for plants to absorb essential elements.


Thanks @monkeyman
I remember this from AN’s line up, way back when.

I found one company selling on amazon , Alpha Chemicals, wondering if there are any particular companies that you would recommend?

1 Like

not really, any of the amazon prime sellers are probably pretty good

1 Like

Custom Hydro Nutrients. Quantrill.

1 Like