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PK Booster FAQ

PK Booster

What Are PK Boosters?

Just like with anything, gardening and cannabis gardening have different terms that you should know. One of those terms is PK Booster. (AKA “bloom boosters”-because they help with the flowering stage) PK boosters are plant nutrients and additives containing mostly Potassium (” K”) and Phosphorus.(” P”) that are essential for assuring a healthy crop.

PK Booster isn’t a brand, it is simply a generic term phosphorus and potassium nutrients that are added to soil to primarily help with a plants flowers and fruits.

Phosphorus’s primary function is to maximize the overall quality of flowers and fruits to make them larger, weigh more, and have more potency. Some of the other tasks of Phosphorus is that it helps with seed development, photosynthesis, and promotes the chemical change that marijuana plats will undergo.

Potassium’s primary purpose is to help with the overall growth of your cannabis plants. For example, potassium is responsible for assisting plants in growing healthy roots and making plant stems and branches thicker when flowering. Additionally, potassium additives help cannabis maximize terpene production.

Technically, PK booster nutrients can encompass everything from synthetic fertilizer, organic fertilizer, and DIY fertilizer. To be a PK boost is just has to add phosphorus and potassium nutrients to the soil.

Why Use A PK Booster?

There are several reasons for using a PK booster for cannabis. One of the main reasons is that it helps speed up the plant flowering stage of growth. By adding a bloom boost to the soil, you will be able to improve your overall flower quality, flower size, and increase THC potency. PK plant nutrients work by fooling your cannabis plants into feeling that it is time to start flowering. As the name implies, added PK would give your plants a “boost” or quicker start into growing cannabis buds. Bud development starting earlier means that the buds will have a longer time to grow and develop.

When Should Phosphorus And Potassium Nutrients Be Added?

PK boosters can be used for not only helping promote healthy buds, but it can also be used if your plants have a PK deficiency. PK additives should be applied to healthy plants during the first week for flowering. You should apply a bloom booster when you first recognized that you have a phosphorus or potassium deficiency. The following are the signs that are commonly associated with a PK deficiency:

What Are Common Signals That You May Have Either A Phosphorus or Potassium Problem?

The most common symptoms of phosphorus deficiency are the following:

Phosphorus Deficiency

Deficiency signs will most likely first appear on the lowest leaves of a cannabis plant.

The first signals of this deficiency are the following:

  • The branches will turn a vibrant red. (Bright red stems alone do not indicate that you have a problem.)
  • Leaves will darken and change into a dark blue, dark green, or a grey-like color.
  • Leaves may look shiny.

If ignored, the following will happen to your plants.

  • Leaves will start getting purple, brown, or bronze spots.
  • Leave will thicken and feel stiff and dry.

Potassium Deficiency

First of all, those who grow hydroponically will likely not have to worry about your plants having a potassium deficiency, which the symptoms, like a phosphorus deficiency, show up on plant leaves. The symptoms are the following:

  • Yellow or brown colors leaf tips that will curl up and look as if they are burnt
  • The plant may seem abnormally taller than the other plants, which is known as stretching. Stretching is bad because it will make a plant’s stems weaker.
  • Start seeing brownish dead spots on the leaves.
  • If left untreated, the spots will turn white.
  • The stems may turn red.

At the final stages of potassium deficiency, the leaves will be smaller, and you may be too late to save your cannabis plant. So, as soon as you find a problem may be present, you need to deal with the situation.

DIY PK Booster

It is quite easy to make your own “DIY” Phosphorus and Potassium booster. A straightforward way to add potassium to your soil is to add banana peels to your mulch pile. Also, you can lightly spread wood ash (light amount-too much can burn plants)into the soil.

This is not technically DIY; organic Greensand works well as a source of organic potassium available at nurseries and Amazon.

Down to Earth Organic Greensand Fertilizer, 5 lb

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To help increase phosphorus levels you can add chicken or fish bones into the soil. All you need to do is chop up the bones in a sturdy blender and mix them into the soil. If you do not want to go through all the trouble of grinding up bones, you should buy bone meal.

Miracle-Gro Nature's Care Organic Bone Meal, 3 lb.


Recommended Synthetic or Organic PK Booster

The following section concerns commercially made PK fertilizer. This list will not explore the most highly rated boosters on Amazon.

Synthetic boosters are man-made and are derived from petroleum products. Potassium sulfate is one example of synthetic fertilizer. Organic fertilizer is made from a natural material, whose primary substance is a natural substance. You can also purchase organic fertilizer from various companies.


There are numerous types of synthetic fertilizers available. One of the most highly rated and best reviewed is Flower Fuel. Flower fuel contains over 40 ingredients. A container will also last a long time because all you have to do to use it is to add 1/4 tsp to a gallon of water.


Jobe’s Organics 9626 Bulb Granular Fertilizer is made from a mixture of chicken bones, manure, and sulfate of potash. It is simple to use as all you have to do is stir-in 1 and a 1/2 cups for every 10′ (transplanted plants) or 4′ (seedlings) of soil area for your nutrient solution.

Jobe's Organics 9626 Bulb Granular Fertilizer, 4 lb, Brown


Final Thoughts

I would recommend that PK booster be used every time for cannabis and not just if you have a P or K deficiency. The choice is yours concerning synthetic or natural boosters. Personally, I don’t have any problem with using store-bought, synthetic fertilizer. If you are into organic gardening there are several PK organic booster options, and Jobe’s Organics 9626, is among the most highly rated on Amazon. Except for adding too much of either nutrient, there is no downside for using PK nutrient additives. So, be sure to follow the directions, and PK booster can be your ticket to healthy flower and cannabis buds that will be the envy of your friends.