marijuana bloom booster

Critiques on Bloom Boosters for Cannabis Flowering

For the most part, nutrient companies create and market their products for novice growers. These products are created for ease of use in small-scale, home cannabis gardens. While these branded, “all-inclusive” fertilizer lines are doubtless invaluable for hobbyist growers, the more advanced agronomist is questioning the necessity of such expansive feeding schedules. As such, there is a movement of growers looking to get “back to the basics” with their cannabis flowering practices.

One of the most formidable trends in the modern gardening marketplace is that of the “bloom booster.” Sold under catchy names and colorful packaging , nutrient companies market bloom boosters as essential fertilizers to be used during cannabis flowering. Moreover, fertilizer companies also include bloom boosters a necessity in their feeding calendars. The kicker is, bloom booster products retail for as much as $250 for 500g. This pricing adds an additional expense on an already expensive practice.

To help the readers get an expert opinion on nutrient usage and bloom boosters, we reached out to accomplished cannabis grower and fertilizer developer Aaron Hoare. Hoare is the founder of Ambrosia Cropz, a three-part powdered nutrient line founded on “bare bones” ideals of simplicity and cost effectiveness. Hoare, like most expert gardeners, emphasizes critical analyses in cannabis cultivaiton. He pays particular attention to plant physiology and fertilizer programs founded on basic plant needs. This notion applies during both vegetative growth and cannabis flowering.

To gain a better understanding of fertilization methodology in relations to cannabis flowering and bloom boosters, Hoare has provided a basic overview of the practices he uses in the development of his own nutrient mixes at Ambrosia Cropz. These procedures are mainly structured around both irrigation and runoff water analytics. This brief study provides some insight into the bloom booster discussion through the eyes of a professional horticulturist and fertilizer developer:

N-P-K Ratios, Water Analysis, and Parts Per Million

While the fertilizer schedules included with most modern nutrient lines are quite valuable for the novice grower, these same gardeners will likely have to learn the basic elemental analyses of fertilizers if they hope to achieve extraordinary harvests. This brings us to the N-P-K ratio featured on all fertilizer products: (N) nitrogen, (P) phosphorous, and (K) potassium.

The three aforementioned elements are known as “macronutrients” and they serve as the essential foods for all plant life. Moreover, different levels of these macronutrients are required for stimulating growth during different phases of a plant’s life. During the cannabis flowering, many horticulturists agree that vigorous flower growth requires higher levels of phosphorous and potassium combined with lower levels of nitrogen. That being said, bloom boosters generally present an N-P-K ratio somewhere in the neighborhood of 0-50-30 or 0-39-25.

According to Hoare, those cultivators looking to critically explore their fertilizer regiments, including the use of bloom boosters, should begin by testing their irrigation and runoff water with a laboratory. These lab readings will show the parts per million of each macronutrient in their water after nutrients are mixed. The test with also show the salt build up in soil. As such, the resultant numbers provide a logical point of departure in deciding whether or not to use bloom boosters. The results can also be used make any other necessary tweaks to a fertilzier feeding schedule.

In the development of nutrient formulas at Ambrosia Cropz, Hoare applies this analytical, data-driven approach for fertilizer development. From these studies, Hoare came to the conclusion that with cannabis flowering, the ideal “ready for plant” irrigation water analysis in parts per million should be as follows: nitrogen 125 ppm, phosphorous 60 ppm, and potassium 165 ppm. It should be noted, again, that Hoare’s figures are formulated via a holistic approach to fertilizer scheduling that takes into account variables like nutrient build up in soil.

Most gardeners (novices and experts included), don’t have the time to consistently test their irrigation and runoff water with a laboratory to get ppm readings. However, these tests are one of the only ways for one to understand exactly what their plants are being fed. That being said, testing both irrigation and runoff water two to three times during a plant’s life will provide enough information to restructure a fertilization program founded on the basics.

For Hoare, it is a better bet to base nutrient formulations on the ppm readings of macronutrients in irrigation and runoff water rather than what is recommended on a nutrient feeding schedule. With this critical approach, Hoare recommends a N-P-K ratio of 7-6-12 during the flowering period. Obviously, these numbers stand in stark contradiction to the 0-50-30 ratios which abound in bloom booster formulations for cannabis flowering.

What does this Mean for Cannabis Flowering?

Plants can only handle a limited amount of fertilization—of any macronutrient—before the process becomes counterproductive. This notion is where Hoare’s ppm data really comes into play concerning bloom boosters. Because, according to Hoare, an overabundance of any macronutrient in irrigation water or a growth medium will actual hinder the uptake of all macronutrients. That being said, as far as bloom boosters are concerned, a majority of standard nutrient feeding regiments already contain sufficient phosphorous and potassium to stimulate cannabis flowering. Moreover, most expert growers agree that too much P and K can be toxic for plants and can actually retard flower growth.

With all things considered, if one wants to follow the more simplistic feeding approaches of Hoare and his contemporaries, they shouldn’t apply bloom boosters if their flowering nutrients already contain 40 – 60 ppm of phosphorous and 150 – 170 ppm of potassium when mixed with water. To reiterate, these numbers are based on a holistic approach to fertilization—taking into account factors like nutrient buildup from months of feeding. Most bloom booster formulations are created “in a vacuum,” so to speak, which don’t consider fertilization processes from planting to harvest.

Ironically enough, evolutions in modern gardening are often times stimulated by contradictions in thought and practice—like those seen in the delineations in theory presented by nutrient lines and “bare bones” horticulturists like Hoare. Concerning bloom boosters for cannabis flowring this difference in methodology could simply boil down to the experience levels of growers. For the novice gardener who doesn’t have the time, or interest, to test fertilizer formulations for maximum output, brand nutrient feeding schedules are an extremely practical choice. There is no doubt that they have given beginners the ability to produce crops unthinkable 20 years ago. That being said, if bloom boosters help these beginners achieve relatively good harvests, they should use them. However, for those more advanced, scientifically minded horticulture experts out there—the writing is on the wall. Not only are bloom boosters expensive, they are not always necessary.

This article originally appeared in the May 2018 edition of Maximum Yield Magazine.

M&F Talent Blog: Are bloom boosters really necessary for successful cannabis flowering? Check out this in depth exploration into plant feeding requirements.

Why You Should Not Use Grow Boosters or Extra Nutrients

Overdoing it with nutrients and grow boosters is one of the most oft-made mistakes when cultivating cannabis. Learn how to use nutrients and grow boosters properly and why “less” is often more when you want to grow cannabis successfully.


If you are a cannabis cultivator who visits grow supply stores in person, or via the internet, you probably know just how many growing products exist out there. The sheer number of options can be overwhelming.

Many companies feature a wide selection, from basic nutrients and fertilisers to grow boosters, bud enhancers and additives galore – not to mention the many other plant-enhancing supplements you could possibly imagine.

Quite often, the grower isn’t just advised to purchase a product or two for their operation. Instead, many of these companies recommend buying a lot of merchandise to make it seem like you can’t go another day without the latest (and most expensive) trend in cannabis plant care.

From that point of view, you can’t really blame growers when they fall for the hype and then, despite their best intentions, literally end up loving their plants to death! Frequent overfeeding and the administration of too many nutrients can cause more problems than they solve – an issue many new cultivators fall victim to.


Considering that nutrient products are highly concentrated and that young plants are especially susceptible to incoming materials, it doesn’t take much to create a harmful imbalance and destroy your crop. Such excessive nutrients can cause all sorts of problems, including root and nutrient burn. When this happens, the roots or the leaves of your plant appear “burnt,” sustaining yellow and black discolorations.

Instances like these may urge you to go out and buy another product to fix the problem, but resist this desire! If your plants are suffering from root burn or nutrient burn, the first thing you should do is stop giving them anything and flush the plants with pH balanced water (6-7 pH) to dilute nutrient build-up.


Some less experienced growers think that cannabis requires some extraordinary skills, as well as a ton of different products. This is a common misconception that could not be further from the truth. Overdoing it, whether this means overwatering or packing your plants with unnecessary additives is a seemingly small mistake with giant repercussions. The good thing is, these slip-ups can easily be avoided!

A seasoned grower will inform you that some basic nutrients, the right amount of light and proper watering is (mostly) all it takes for a successful cultivation cycle. Even if some manufacturers claim their products “enhance” the flavour of your yield or make similar unsubstantiated claims, they often encourage the exact opposite effects.

The best case scenario when using certain unhelpful products will result in harsh or bitter tasting weed. The worst case scenario? Your entire crop starts shutting down plant by plant. If you really want to grow cannabis to achieve the most flavour and potency, you should keep things as simple and natural as possible.


When it comes to growing tips, first thing’s first – do NOT get lured in by smarmy salesmen looking to make a buck off their “miracle products.” There are few instances where grow boosters or additional additives are necessary to improve the quality of your crop.

Start out with acquiring sufficiently size pots, around 11-18 litres. You should be able to find a business that sells flower pots and other gardening supplies nearby. They don’t need to be special, just make sure they have holes in the bottom to allow for optimal drainage. You should also make it a habit to clean your pots before use as this can minimise the risk of plant diseases, fungi and other pathogens.


Most potting mixes (soils) available for purchase are already pre-fertilised. In theory, this means your plants don’t require additives. The three essential minerals for plant growth are nitrogen, phosphorus and potassium (NPK), although potting mixes normally contain other beneficial minerals like calcium and iron. Nitrogen is the mineral that your plants need most when they grow “green stuff“ like leaves and stems. Phosphorus is necessary for good root spread and growth, as well as for flowering. Potassium encourages plants to grow vigorously.

You can usually find the correct N-P-K ratio displayed on your bag of potting mix or on your bottle of nutrients in the form of three numbers, which might look like: 12-14-24. In this case, the mix contains 12% nitrogen, 14% phosphorus and 24% of potassium, which is normally considered to be the best balance for cannabis cultivation.


You could have the “best” nutrients and an ideal feeding schedule, yet it will all be in vain if the pH balance of your water or nutrient solution is not correct. The reason for this is that cannabis can only take in nutrients when the water (and then the soil) is within a certain pH range. For growing in soil, the correct pH balance for your water should be between 6.0 and 6.3. If it isn’t (which can be the case when you use water right off the tap, or if you add anything to the solution), the plant cannot take in nutrients, even if they are present. This culminates in nutrient deficiencies, causing your plants to become sick, sometimes beyond repair.

This is why a pH measuring stick or solution, along with products that either increase or decrease your water’s pH if needed, is probably the most important item every grower should own.

The issue with so called grow boosters is that they can dramatically alter the pH, which will incite all kinds of disastrous outcomes in no time.

Usually, if your water’s pH is on point and you are using a quality substrate, there won’t be much standing in the way of a healthy and successful crop! You likely won’t need any type of additives at all, so long as your potting mix contains some nutrients.

Too often do those new to growing cannabis (even some who are experienced) tend to rely on