Good day Scotty, Dude, Guru and all of the DGC, I have been hearing the term “Brix” over and over in podcasts lately. While it is far from a new concept, I wondered how it applied to Cannabis and if I should be concerned about it. So I did another one of my overviews. Now, I know you all are some smart dudes, is there anything I may be missing or not understanding? I would sure love your input on my understanding of brix.
I wrote this in order to better understand it for everyone. I know it is long, but I hope you enjoy and learn as I did. For many people, brix is a word commonly associated with the wine industry. Brix is important to the sweetness of the grapes which makes all the difference in regards to the taste of the final product. However, we don’t eat or drink raw Cannabis, so why is brix important?
Adolph Brix developed this scale in the mid 1800s and it was popularized by Dr Carey Reams in the mid 1900s. Although brix had been used by citrus and grape growers for years, Dr Reams formulated a brix chart that covers most common fruits and vegetables, as well as forage crops.
THE ROLE OF BRIX VALUES IN TRADITIONAL AGRICULTURE
In a single sentence, high brix levels will improve the flavor, nutrition and shelf life of the produce as well as potential IPM (Integrated Pest Management) benefits.
Brix is a measurement of soluble solids in the sap of a plant. Most commonly, brix is thought of as sugars, but brix really is a measurement of sugars, vitamins, minerals, proteins and other solids. However, sugars are the most abundant soluble solid in many fruits and vegetable juices, therefore, brix values primarily represent estimates of sugars in fruits and vegetables. When used in the context of Cannabis, we are testing the leaf, and those results may also show salts in the dissolved solids.
Higher brix levels in food have been associated with elevated nutritional values as well as having a sweeter, more desirable taste. Field managers are able assess harvest readiness for grapes, melons and other crops using brix values.
Using the Poor, Average, Good, Excellent (P.A.G.E.) scale for brix levels in various fruits and vegetables, home gardeners can take the taste and nutritional quality of their crops to the next level. You can also easily and quickly determine who has the best produce at your local farmers market by using a hand-held refractometer. Interestingly, fruits and vegetables with high brix levels are superior for storage, as they will not rot or mold, the simply dehydrate.
To find the brix levels of any plant, fruit or vegetable, you can use a small refractometer. Prices range anywhere from $20-$200 for a unit and the majority of them are small enough to fit in your pocket and bring out into the field with you. To find the brix value, squeeze a few drops of plant sap into the refractometer. This tool will then shine a light at the liquid sample, where it bends or refracts the light in a predictable manner. The more soluble solids that are in the liquid sample, the larger the refraction will be, which indicates a higher brix value.
Higher brix levels have also been associated with plant health and potential IPM benefits. Field managers that regularly check plant brix levels are able to identify connections between brix values, crop health and conditions their crops experience. The brix value in a plant has a lot to do with nutrient availability and balance in the soil. Low brix values mean poor nutrition and this in-turn means weaker plants, which pests love. Plants with a brix value of over 12% are much less likely to have pest issues. Brix value alone cannot describe the overall health of a crop, soil or farm, but it can give you a glimpse.
HOW DO YOU INCREASE BRIX?
To the chagrin of those that do cross-fit…. I mean grow organically, seemingly that is one of the best ways to get plants to have higher brix levels. By focusing on soils that are rich in organic matter, beneficial bacteria and fungi, over time you can raise these levels naturally.
Before we get to soil, you can’t have high brix without proper sunlight, or in the case of indoor cultivation, proper intensity and DLI (Daily Light Interval). This is due to the lights role in producing sugars through photosynthesis. Before you go and build your dream, high brix soil, make sure you have adequate light.
As with all living soils, the road to high brix starts with plenty of beneficial soil microbes. Microbes are in the soil to make nutrients available to plants. They ingest one form of the nutrient and excrete a form of nutrient that is more bioavailable to the plants.
Once you have the microbes in place, you’ll want to ensure a good supply of Calcium to the plant. It takes good microbial activity to make calcium available in the soil. If calcium availability and uptake are optimized, other mineral uptake will be more balanced and effective. Calcium increases cellular structure in plants that keep the Xylem and Phloem moving freely. High brix foods are higher in calcium than low brix foods. A calcium deficiency in the plant will almost certainly effect brix levels, but it is important not to provide Calcium in excess. Too much calcium will lock-out several other important macronutrients like Phosphorus and Potassium as well as micronutrients like Boron.
Speaking of Phosphates, they also play an important part of the high brix equation. Phosphates are a catalyst that transports nutrients within the plant, they can act as the trucker moving nutrients within the plant. Dr Carey Reams once said “ Available phosphates determine sugar content in plants”. When he said that, he didn’t mean that high brix foods are necessarily high in phosphates; rather they are significantly higher in calcium, sugars and trace minerals, but phosphates are essential to get them to where they are needed. Phosphates also play a major role as the energy source in the Krebs cycle, which is a fancy way of saying that phosphates help the plant get more energy out of sunlight.
Having plant available iron in the soil helps with the efficiency of sugar production. During photosynthesis, chlorophyll manufactures sugars and the micronutrient, iron, acts as a catalyst. Humic and Fulvic acids are a great way to make iron in soil more plant available.
Organic matter provided by humates make nutrients more available to the plant. Technically, Folvic acid is refined Humic acid and all humates contain some fulvic acid. Both humic and fulvic acid make other nutrients available to the roots, fulvic acid also delivers nutrients directly into the plant and then operates as part of the internal delivery system. Being able to move sugars and nutrients around is vital for good brix levels in plants. Fulvic acid greatly assists in this.
Since we’re on the subject of acids, you’ll want to include some amino acids too. Amino acids are the building blocks of all life. Plants use amino acids to build proteins which are then used to build plant matter. By providing amino acids, the plant does not need to expend it’s sugar energy to make these proteins. Amino acids can also greatly increase the uptake of Calcium, which we know is important for strengthening the stem and vascular systems. L-Amino acids help the absorption and transport of minerals throughout the plant by chelating the minerals.
Kelp or seaweed extracts contain beneficial micronutrients, natural plant hormones and natural sugar in the form of Mannitol. Mannitol is a natural chelation agent for micronutrients and has been shown to be helpful in the plants transport system. Kelp / seaweed also helps in building root mass through stimulating cell division. When it comes to Cannabis, there is an old saying – “the bigger the roots, the bigger the fruits”. Which in my experience is certainly true.
Other items you may want to add into your soil mix include earthworm castings, mycorrhizal inoculants, compost teas, humus and rock dust. All of the above items can be added to your custom soil mix or a standard 1/3 compost, 1/3 peat or coco and 1/3 vermiculite mix.
FEEDING FOR BRIX
In regards to the traditional N-P-K, levels of higher brix in plants are often associated with lower levels of nitrates. Ammonium Nitrates (NH4+) burn carbohydrates and reduce the brix levels in plants.
Because microbes form an important part in the process of making nutrients plant available, in the effort to increase brix, the use of synthetic nutrients is discouraged. Salts tend to disrupt the soil parameters that the microbes prefer to dwell in.
If you would like to use a soil drench, there are a few carbohydrate additives that can be used on the root zone. A good carbohydrate additive will reduce the amount of sugars the plant transports down to feed the beneficial microbes. In some cases, roots will absorb sugars instead of shed them and this increase brix within the plant.
An excellent option for feeding your plants in an effort to boost brix levels would be foliar applications. A well made mix can have a tremendous impact on raising brix values in plants. Phosphates, calcium, boron and other micronutrients can be applied as foliar sprays. Increasing phosphates in the plant through foliar sprays allows the Krebs cycle to transfer more energy within the plants, which makes the plant more efficient in storing energy as sugar from the photosynthesis process.
When a foliar program is properly applied the mineral density as well as the carbohydrates or sugars within the plant is increased. Some of these additional sugars and minerals travel down to the roots and are excreted out as exudates, which feed the beneficial microbes. They in-turn make minerals more available to the plant, which are taken up through the roots and increases the total dissolved solids in the plant. This process explains how foliar applications can increase brix readings.
KEY QUESTIONS REGARDING YOUR NUTRIENTS AND HIGH BRIX
- How much calcium is available for the plant to build healthy cells with?
- Is Calcium in the correct ratio to Magnesium?
- Does the soil have enough Phosphates to carry other nutrients into and provide energy transfer inside of the plant?
- Is there a wide spectrum of trace minerals available to the plant, meaning, in bioavailable form?
- How active is the soil biology (microbes)?
HOW DOES THIS EFFECT THE CANNABIS GROWER?
Brix testing gives you a good, general, overall look at plant health and soil nutrition. But by no means is it a definitive test that will show whether a specific nutrient is in excess or deficiency. One plant diagnostic assumption we can make though, is that if the brix values are low, there likely is a calcium deficiency. If there are more sugars and other beneficial components like minerals and amino acids (lives building blocks), the plant can build more coveted compounds like oils, flavors and resins.
On average, a brix value of 12% is excellent and anything below a 7 is poor in regards to brix and IPM. High brix is thought to deter insects for a few reasons, the first being that with elevated sugar levels, when insects take a bite, the sap ferments to alcohol inside of the insects body. The insects can’t digest the alcohol and they die. This appears to offer natural resistance with no artificial or toxic chemicals. I did not find Cannabis specific brix levels and correlations to health, but one website did toss their idea of ideal brix for Cannabis at 12-15%.
Dr. William Albrecht, whom is regarded as a premier soil scientist of his time has said, “Insects and disease are the symptoms of a failing crop, not the cause of it. It’s not the overpowering invader we must fear, but the weakend condition of the victim”. It was concluded that brix alone could not explain the lack of insect pressure, but the influence and combination of various nutrients and overall plant health carried more significance.
As ornamental growers, we aren’t very concerned with the taste of the raw buds. We are however concerned with the taste that the terpenes of the plant can offer. Wine grapes are known to carry many monoterpenes as well as a few sesquiterpenes although the direct connection to brix has not been established, that I am aware of.
As an overall guide to plant health, a Sap analysis would be more accurate and specific, but those are costly and not a likely option for the home grower. Performing a simple brix test at various stages of your plants growth can give you a window into the overall health and mineral uptake of the plant.
Trying to raise the levels of brix by what and how you feed the plant offers the grower an opportunity to try something new and outside of their comfort zone. Good growers are always looking for a new challenge. This also encourages the use of organics, which many people are gravitating to.
In the garden, the way you defoliate can have an impact on your plants brix levels. Young leaves suck more sugars, because they are still growing. Older leaves, they’re happy, they require much less sugars. Conversely, we all know that the leaves make sugars during photosynthesis and if you remove the majority of them, you can stall growth by stalling photosynthesis. Go sparingly when you defoliate and keep some of the top leaves, because they catch the most sunlight. Growing buds are going to be a constant draw on the plants sugar reserves, which may be another important reason that we are checking for brix.
The brix scale was created to measure sap at an ambient temperature of 68 degrees. Many refractometers today account for this and will do a conversation, but even if yours doesn’t, you can find a chart online to correlate your results and temperature to the main chart for accuracy.
As night gets closer, the plant will send sugar down to the roots to feed the beneficial organisms. This will cause brix levels to fall. It is important that you check your brix levels at the same time everyday to create an accurate graph of your true levels.
If you grow outdoors, shade will also cause brix levels to drop temporarily, due to reduced photosynthesis.
A 100g sample of a solution that measures a 50 brix value, has 50g of sugars and other dissolved solids and it also has 50g of water. This should give you an idea for how actual sugar content relates to brix value.