How to Use Bloom Boosters for Cannabis Plants?

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Added 08 January 2023

Imagine growing a cannabis plant only for it to develop small, airy flowers that have a dull appearance, aroma, or flavor. That’s every grower’s nightmare — months of hard work down the drain. 

But why would this happen to your cannabis plant? There are various reasons, but the most common one is that your plant never got the right nutrients.

But wait — this problem is quite easy to prevent. All you have to do is use bloom boosters. These are fertilizers specifically designed to be used during the flowering stage of the cannabis plant, and if you use them properly, you can notice a significant improvement in your plant’s yields.

In this article, learn all about bloom boosters and how to use them to grow healthy cannabis plants with sticky, aromatic flowers.

What are Bloom Boosters?

What are Bloom Boosters?

Throughout its growth cycle, cannabis uses a variety of nutrients in varying quantities. For instance, a vegetating cannabis plant will require different nutrients than a plant in the flowering stage. 

Among the various nutrients, the three most important nutrients a cannabis plant requires are nitrogen, phosphorus, and potassium — the three macronutrients. During the vegetative stage, cannabis requires more nitrogen than the other two macronutrients, typically an NPK ratio of 3:1:1.

This is because nitrogen is crucial for a growing cannabis plant — vegetative cannabis can contain up to 4% nitrogen in its tissues above the ground! Nitrogen helps build chlorophyll to promote photosynthesis and amino acids that build proteins for the plant’s structure. 

Since nitrogen fuels the growth of cannabis plants, it is required in more quantity during the vegetative phase. But during the flowering stage, nitrogen takes a back seat, and phosphorus and potassium take over. More on these nutrients later.

This is where bloom boosters come into play. Bloom boosters are fertilizers containing phosphorus and potassium, which can help your plant develop better and richer buds during the flowering stage.

What Nutrients do Bloom Boosters Contain?

What Nutrients do Bloom Boosters Contain?

Bloom boosters come in a wide variety — some contain a few nutrients while others contain many more, and you can pick one depending on your preferences and goals. However, some of the common nutrients most bloom boosters contain are as follows.

1. Phosphorus 

Phosphorus and potassium are two of the most important nutrients your cannabis plant requires during the flowering stage. Here, phosphorus makes up a crucial part of the nucleic acid structure, which carries information in the plant cells. 

These structures are crucial for protein synthesis, tissue development, and cell division. Due to this, during the flowering stage, phosphorus helps the cannabis plant develop flowers and roots, which leads to improved yields.

2. Potassium

Potassium is the other macronutrient that is crucial during the flowering stage of a cannabis plant because it aids in various microscopic movements within the plant. This element helps with the movement of carbohydrates, nutrients, and water. 

Additionally, potassium also helps in the production of adenosine triphosphate (ATP), which is the cellular unit of energy. Potassium is also partly responsible for the function of stomata, which play a crucial role in gas exchange. 

During the flowering stage, cannabis plants experience a final stretch, where some strains even double in height in a couple of weeks. During this stretch, potassium is crucial to help the plant develop strong stems. 

These abilities of potassium come together to help the plant grow bigger buds and produce more energy during the flowering stage.

3. Micronutrients

Apart from macronutrients, most bloom boosters also contain various other micronutrients like magnesium, sulfur, and calcium. These nutrients further help your cannabis plant develop better buds.

Here, calcium and magnesium are usually found in the form of calcium bicarbonate and magnesium sulfate, respectively. These two nutrients help a flowering cannabis plant fulfill various processes. 

At the same time, calcium and magnesium prevent nutrient antagonism where one nutrient may stop the other from being absorbed by the roots. This is especially the case if you feed too much potassium to your plant. This is why it is recommended to choose bloom boosters that at least contain calcium and magnesium to prevent nutrient antagonism.

Other micronutrients present in many bloom boosters have various other potential benefits for the plant — they fill the gaps in the plant’s nutrient needs, create a rich substrate, and help the plant utilize macronutrients more efficiently. 

Should You Use Bloom Boosters for Growing Cannabis?

Should You Use Bloom Boosters for Growing Cannabis?

There are hundreds of things you can buy that claim to help improve your plant’s growth, but that doesn’t mean you use all of them. And do bloom boosters fall in the same category?

Not really. Bloom boosters aren’t a gimmick and are quite helpful for many growers, especially novice growers. Here are some advantages of using bloom boosters in your cannabis garden.

1. They Help Grow Bigger, Better Flowers

The biggest benefit of using bloom boosters is that they can help your plant grow bigger, better flowers. As mentioned earlier, bloom boosters contain all the right nutrients your plant requires during bloom, so these fertilizers fill in the gaps and ensure your plant gets everything it needs.

The result is efficient bud development with dense, sticky, and potent flowers. The buds will likely grow more trichomes and terpenes, leading to better aroma, flavor profiles, and potency, too.

2. They are Convenient and Easy to Use

Bloom boosters aren’t the only way to improve your plant’s bud development. You can also use various training methods, invest in specialized light panels, add more carbon dioxide to the grow room, etc. 

But these alternatives come with a major catch — they are difficult to execute, require a lot more focus, and can get really expensive sometimes. However, with bloom boosters, you don’t have to worry about such problems.

Bloom boosters are quite easy to use and you don’t have to spend too much time either. Even novice growers with basic feeding skills can efficiently use bloom boosters on their cannabis plants.

3. They are Accurate

Unlike other supplements, bloom boosters are much more accurate. Most bloom boosters are third-party tested — avoid if they are not — and come with specific instructions on using them. 

So, with high-quality bloom boosters, you are sure to give your plants exactly the amount of nutrient it needs without leading to nutrient imbalance or lockout. All you need to remember is to buy high-quality ones from reputable suppliers.

Do Bloom Boosters Have Any Downsides?

nutrient burn

Yes, bloom boosters do have some downsides that every user must be aware of. These downsides aren’t usually dealbreakers, but they give you a clearer perception of bloom boosters and let you decide if they are right for your garden.

Here are some of the common disadvantages of bloom boosters.

1. Can Cause Overfeeding

One of the biggest downsides of bloom boosters is that they are easy to overfeed, especially for novice growers. And overfeeding bloom boosters to your cannabis plant can have drastic consequences.

If you overfeed bloom booster to your plant, you can cause nutrient burn on the leaves and roots of the plant, which can hamper your plant’s ability to grow buds well. 

Additionally, too much bloom booster at a time can cause nutrient antagonism, where some nutrients may fail to be absorbed by the plant completely. Even this can have a drastic impact on your plant’s overall yield.

2. Can be Harmful to the Soil

Not all bloom boosters are organic — some include chemicals that may disrupt your plant’s soil life. Some bloom boosters can also affect the natural nutrient cycling, which can further impact your plant’s yield.

So, when choosing bloom boosters, it is crucial that you choose high-quality products with minimal inorganic content. Inorganic matter in bloom boosters isn’t necessarily harmful as some can benefit the microbial life in the soil, but it is best to avoid them.

How to Use Bloom Booster for Cannabis Plants?

How to Use Bloom Booster for Cannabis Plants?

Using bloom boosters is straightforward, but it can still be a little confusing for first-timers. But don’t worry, we've got your back. Here is a step-by-step guide on using bloom boosters for cannabis plants.

1. Gather the Supplies

The first step is obviously to gather all the things you need, such as the following:

  • Bloom booster fertilizer of your choice 
  • Filtered water 
  • A pH meter
  • A nutrient meter
  • pH up/down solution (may be required)
  • Mixing cup
  • A syringe 

2. Schedule the Right Time 

The next step is to figure out the right time. If you are growing photoperiod cannabis, you should ideally start using bloom boosters from week 2 of the flowering stage after you switch the light cycle to 12/12. 

For autoflowering cannabis plants, the same rule applies but figuring out the exact day may be confusing. In that case, look at the nodes. If you see signs of any flower developing, it’s a good time to start using bloom boosters. 

An often overlooked aspect of timing is the health of the plant — your cannabis plant must be healthy when using bloom boosters. 

3. Follow the Instructions

Bloom boosters come in a lot of variety, so it is crucial that you follow the manufacturer’s recommendations. The recommendations will specify how much bloom booster you need to use per liter of water.

Here, you can even take a safer approach by using a more dilute concentration and building the dosage up to the recommended levels over the next few days. 

For example, the manufacturer may recommend you to use 2 ml per liter of water, but you can use 1 ml for the first day and then build your way up to 2 ml to ensure your plant does not exhibit any signs of nutrient toxicity or burn.

4. Mix the Solution

Once you have the right dosage on hand, it’s time to mix it with water. You can use a plastic applicator or a scale to measure the correct amount of bloom booster. Next, fill a container with a liter of filtered water and add the bloom booster to it and shake well. 

5. Measure the pH of the Solution

pH is crucial for nutrient absorption — the wrong pH can inhibit the roots from absorbing the nutrients. So, you need to measure the pH of the solution to ensure it is in the right range.

The pH should be between 5.8 to 6.2. If the pH is far off, you can use a pH up/down solution to rebalance the pH. It is also a good idea to check the pH of the substrate right now to prevent it from interfering with the solution’s pH.

6. Feed Bloom Booster to Your Cannabis

Now comes the time to feed your plant the bloom booster you have prepared. Here, you can either use a watering can, reservoir, or drip line — similar to your regular feeding routine. 

But once you feed your plant bloom booster, remember to keep an eye on your plant for the next 24 hours. Sometimes, some strains can exhibit signs of nutrient toxicity since bloom boosters are highly concentrated solutions that some plants cannot handle. 

In most cases, your plant will be happy and safe, but on the off chance you notice any signs of nutrient burn, you should dilute the solution by adding more water to it for the next few days. 

Are Bloom Boosters Safe for Cannabis Plants?

Are Bloom Boosters Safe for Cannabis Plants?

Bloom boosters have come under some flack in the growing community, which has led to some controversy. The two most debated aspects of bloom boosters are that it leads to salt buildup in the substrate and most cannabis plants don’t really need it. How true are these claims? Let’s take a close look at the controversy surrounding bloom boosters.

1. Bloom Boosters Cause Salt Buildup

Bloom boosters contain some salts, like magnesium sulfate and monopotassium phosphate. These salts are crucial for your plant’s development. For example, monopotassium phosphate is a source of potassium and phosphorus. 

However, overfeeding these salts to your plant can lead to salt buildup in the substrate, which can lead to the burning of the plant tissues. These salts can also alter the substrate’s pH levels, which can block the intake of other nutrients (nutrient lockout).

This is why many growers avoid bloom boosters to prevent salt buildup. But if you use the right bloom booster and follow the manufacturer’s recommendations, you likely won’t face this problem.

It is also wise to know as much as you can about the strain you are growing because some strains are naturally less sensitive to salt buildup in the substrate. In any case, you should be more conservative with bloom boosters when starting out.

2. Cannabis Plants Don’t Need Bloom Boosters

Many other growers believe that bloom boosters are just marketing gimmicks and that your plant can grow just fine without them. Of course, cannabis plants can thrive without bloom boosters — as long as you give the right nutrients to your plant at the right time. 

But with bloom boosters, you are raising your chance of success by a great margin by ensuring your plant gets the right nutrients while talking a lot of the guesswork and labor out of the process. 

So yes, cannabis plants don’t really need bloom boosters, but a little more help never hurts anybody. 

Bloom Booster FAQs

You may still have some queries about bloom boosters, so here are the most common questions we get asked about bloom boosters, answered.

When Should You Use Bloom Boosters on Cannabis Plants?

Bloom booster, as the name suggests, must be used when your cannabis plant is flowering, but that’s still a very wide window of time. Cannabis plants transform from the first week of flowering to the last. 

So, it is crucial that you stick to a narrow window of time to use bloom boosters on your cannabis plants. The best time to use bloom boosters on cannabis is from the second to fourth week of the flowering stage.

Avoid using bloom boosters during the first week of flowering as this is the time when your plant will experience its final stretch. Wait until you notice any signs of bud development and then use bloom booster. 

Protip: look at the nodes of the plant — if you notice any flowers starting to develop there, it’s time to use bloom boosters on your cannabis plant.

How Much Bloom Booster Should You Use on Cannabis?

Bloom boosters come in a variety of concentrations and formulas, so it is hard to say exactly how much to use. For this, you need to follow the manufacturer’s recommendations as the quantity varies from product to product.

If you are worried about your plant or want to play it safe — because bloom boosters are highly concentrated — you can also use a diluted bloom booster than recommended during the first few days. Check for any signs of nutrient burn and then move up to the recommended dosage.

Do Bloom Boosters Have to be Labeled as Bloom Boosters?

Not always. Sometimes, you may find fertilizers that are terrific bloom boosters but the packaging might not contain the term "bloom booster" anywhere. You have to look at the contents of the fertilizer, especially the NPK ratio, to figure out if it can work as a bloom booster.

A vegetative fertilizer would have an NPK ratio of 3:1:1, but if the NPK ratio is 1:3:2 or close, it is a bloom booster as it is rich in potassium and phosphorus.

Is Too Much Bloom Booster Harmful to Cannabis Plants?

The more the merrier formula does not work for cannabis plants, especially when considering bloom boosters. These products are already highly concentrated, so if you feed your plant too much, it can experience a nutrient lockout or burn quickly.

Always follow the manufacturer’s recommendation on dosing, and if possible, be more conservative during the first few days to ensure you don’t overfeed bloom boosters to your cannabis plant. 

Do Bloom Boosters Guarantee Better Yields?

In a utopian world, every fertilizer would guarantee better yields or results. But that’s not the world we live in. Bloom boosters increase your plant’s chances of a better yield, but a lot of other variables come into play.

The most important variable is how you feed the fertilizer to your plant. If you don’t give the right quantity, you may not see the desired results. Additionally, other factors like pH, temperature, humidity, etc. can also affect your plant’s yield. 

Where to Buy Bloom Boosters for Cannabis?

Bloom boosters are readily available in most gardening or horticultural stores. Ideally, you should buy cannabis-specific bloom boosters, but generic ones would also work well as long as they contain the right nutrients.

If they are not available in your local brick-and-mortar stores, you can also order them online. They are not so expensive. Just remember to pick a product from a reputable manufacturer with good reviews.

Summary: How to Use Bloom Boosters for Cannabis Plants?

Most growers grow cannabis for one reason — its flowers. That’s basically the whole point of cultivating cannabis for growers like you and us. We want our plants to grow buds that are big, bushy, resinous, and potent.

But even minor faults during the cultivation can prevent your buds from developing into what you desire. 

Thanks to bloom boosters, a lot of the risks can be minimized. Bloom boosters are rich in potassium and phosphorus, along with other micronutrients, that your plant requires in higher quantities during the flowering stage. Use bloom boosters to give your plant all the nutrients it needs during flowering.

When picking bloom boosters, remember to choose a high-quality product and always follow the manufacturer’s recommendations. Bloom boosters are highly concentrated and it is easy to overfeed it to your plant, which can lead to nutrient burn or lockout.

And if you want to take it easy, you can even use a more dilute solution during the first couple of days and look for any negative reactions. 

You also don’t want to feed bloom boosters at the wrong time. Wait until the flowering stretch of your plant is over and look for signs of bud development at the nodes before feeding your plant bloom boosters.

Bloom boosters are effective, but not the only way to improve your plant’s yields. There are many other methods. Stay tuned to know all about them.


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