Cannabis Classroom

08/26/2026

Grab your copy of the Hardcover or the eBook, available now Barnes and Noble online.

08/25/2026

🌿 Tuesday Tips, More Nutrients Can Sometimes Create a Deficiency

It sounds backwards.

If a cannabis plant looks deficient, the natural reaction is often to give it more nutrients.

But sometimes, too much of one nutrient can actually make it harder for the plant to absorb another.

This is called nutrient antagonism.

🧪 Cannabis research has shown examples such as:

• Higher potassium competing with calcium and magnesium uptake
• Excess magnesium reducing calcium and potassium uptake
• Interactions between nitrogen, phosphorus, and potassium changing plant growth and nutrient balance

So a plant can have plenty of a nutrient sitting in the root zone and still struggle to take up enough of it.

That means a yellowing or spotted leaf does not automatically mean:

"Add more fertilizer."

Before increasing nutrients, check the whole system:

🌱 Root health
💧 pH and irrigation
🧪 Feed concentration
⚖️ Nutrient balance
🌡️ Environment and transpiration

💡 Tuesday Takeaway:

Plant nutrition is about balance, not abundance.

Sometimes the solution to a deficiency-looking problem isn't adding more.

It's figuring out what's preventing the plant from using what is already there.

08/24/2026

🌿 Monday Motivation, Genetics Aren't the Whole Story

A cannabis seed contains a genetic blueprint.

But having a gene doesn't necessarily mean that gene is always being used the same way.

🧬 That's where epigenetics comes in.

Epigenetics involves changes in how genes are regulated without changing the underlying DNA sequence itself.

Think of DNA as the instruction manual.

Epigenetic mechanisms help determine which instructions are easier or harder for the plant to read.

🌱 These mechanisms include things like:

• DNA methylation
• Changes to proteins associated with DNA
• Regulation of how tightly DNA is packaged
• Signals that influence whether certain genes become more or less active

Researchers are now studying these processes in cannabis, including how plant development, tissue type, stress, and even long-term cloning or tissue culture may influence epigenetic patterns.

But there is an important distinction:

Epigenetics does not mean the environment rewrites a plant's DNA.

The genetic code can stay the same while the way certain genes are regulated changes.

Biology determines how that potential gets expressed.

The deeper we look into cannabis, the more we discover that the plant is not simply following a fixed genetic script. 🌱🧬

08/21/2026

🌿 Friday Facts, A Cannabis Plant Can Look Healthy and Still Carry HLVd

One of the more concerning pathogens in modern cannabis cultivation can sometimes hide without obvious symptoms.

It's called Hop latent viroid, or HLVd.

🧬 And interestingly, a viroid is not the same thing as a virus.

Viroids are extremely small infectious RNA molecules. They don't have the protein coat that viruses do, but they can still interfere with normal plant biology.

An infected cannabis plant may eventually show:

🌱 Stunted or weak growth
🍃 Smaller or abnormal leaves
🌼 Reduced flower development
🔬 Changes in cannabinoid and terpene production
📉 Lower overall yield and quality

But here's what makes HLVd especially tricky:

Some infected plants can remain asymptomatic.

They may look healthy while still carrying the viroid, allowing infected clones or plant material to unknowingly spread it through a grow.

Research has also shown HLVd can spread through contaminated plant sap and infected roots, making sanitation and clean propagation material extremely important.

💡 Friday Takeaway:

Not every plant-health problem announces itself with yellow leaves or visible damage.

Sometimes the most important thing happening inside a cannabis plant is something you can't see at all.

08/20/2026

🌿 Thursday Thoughts, Cannabis Has an Immune System Too

Cannabis doesn't have antibodies, white blood cells, or an immune system like ours.

But that doesn't mean the plant is defenseless.

When plant tissue detects certain pathogens or damage, it can activate chemical defense pathways around the affected area.

And here's the fascinating part:

🧬 The response doesn't always stay local.

Chemical signals can help prepare tissues elsewhere in the plant for possible attack, a phenomenon plant scientists call systemic acquired resistance, or SAR.

Think of it less like the plant "healing" and more like the plant putting other tissues on alert.

🌱 Plants can respond by:
• Activating defense related genes
• Producing protective proteins and compounds
• Strengthening certain cellular defenses
• Preparing distant tissues to respond more effectively

This does not mean intentionally exposing cannabis to disease is beneficial. Disease prevention and good cultivation practices still matter.

💭 Thursday Thought:

A cannabis plant may look completely still, but biologically it is constantly sensing its environment, exchanging signals, and adjusting its defenses.

There is a lot happening inside that plant that we never see.

Did you know plants could warn their own distant tissues about a threat?



cannabisclassroom.org

08/19/2026

📣 A Special Cannabis Classroom Announcement

For the first time, the knowledge we’ve been building through Cannabis Classroom is now available in a physical book through Barnes & Noble online. 📚

Cannabis Classroom: An Evidence-Based Guide to Understanding Cannabis was created for people who want to understand this plant beyond the surface.

Cannabis is an incredibly complex plant, and there is still far too much misinformation surrounding it. This book was created to make the science easier to understand while still respecting the evidence behind it.

💚 A reaction helps.
💬 A comment helps.
🔁 Sharing this with someone who wants to learn about cannabis helps tremendously.

And for anyone who would like their own physical copy, it is now available through Barnes & Noble online.

📖 Cannabis Classroom: An Evidence-Based Guide to Understanding Cannabis

Thank you to everyone who has learned, questioned, shared, and grown with Cannabis Classroom. This is another way of making sure cannabis education reaches beyond a Facebook post and continues to live somewhere people can return to again and again. 🌿📚

Barnes & Noble’s online bookstore for books, NOOK ebooks & magazines. Shop music, movies, toys & games, too. Receive free shipping with your Barnes & Noble Membership.

08/18/2026

🌿 Tuesday Tips: Your Growing Medium Can Hold Nutrients

When you feed a cannabis plant, those nutrients do not simply sit in the root zone waiting to be absorbed.

The growing medium can actually hold onto certain nutrient ions.

This is where cation exchange capacity, or CEC, comes in.

🧪 Think of CEC like the medium's nutrient parking lot.

Negatively charged surfaces in soil or growing media can attract and temporarily hold positively charged nutrients such as:

🌱 Calcium
🌱 Magnesium
🌱 Potassium
🌱 Ammonium

Roots can then exchange other ions with those surfaces and access some of those nutrients.

Different growing media have different CEC characteristics, which is one reason soil, coco, and other substrates do not manage nutrients exactly the same way.

For example, coco can interact strongly with calcium, magnesium, potassium, and sodium. This is why properly preparing and managing coco matters.

💡Tuesday Takeaway:

Growing cannabis is not only about what nutrients you add.

It is also about understanding what happens to those nutrients after they enter the root zone.

The medium is part of the chemistry too. 🌱



cannabisclassroom.org

08/17/2026

🌿 Monday Plant Science, Your Cannabis Plant Counts Light All Day

Growers often focus on one lighting number: PPFD.

But PPFD only tells you how much photosynthetically active light is hitting the canopy at that moment.

Plants experience something bigger.

☀️ Daily Light Integral, or DLI, measures the total amount of photosynthetically active light a plant receives throughout an entire day.

Think of it like this:

PPFD = how fast light is arriving
DLI = how much light the plant collected by the end of the day

That means two cannabis plants could receive the same PPFD but end the day with very different amounts of total light if their photoperiods are different.

For example, a plant receiving the same light intensity for 18 hours will accumulate more daily light than one receiving it for only 12 hours.

🧬 Why does that matter?

Light provides the energy that powers photosynthesis, and photosynthesis produces the carbohydrates cannabis uses to build:

🌱 Roots
🍃 Leaves
🌿 Stems
🌼 Flowers
🧪 Secondary metabolites

But more light is not automatically better.

A plant can only use light effectively when its genetics, temperature, water supply, nutrition, CO₂ availability, and overall health can support that level of photosynthesis.

💡 Monday Takeaway:

Don't only ask, "How bright is my light?"

Ask, "How much usable light is my plant receiving over the entire day?"

That is the difference between looking at one moment and understanding the plant's complete light environment.



cannabisclassroom.org

08/14/2026

🌿 Friday Facts, Cannabis Moves Sugar Around the Plant

A cannabis plant does not use everything it produces exactly where it was made.

During photosynthesis, mature leaves capture light and use carbon dioxide and water to produce sugars.

But those sugars can then be transported to other parts of the plant.

🔬 Plant scientists describe tissues as sources and sinks.

🍃 Sources are tissues producing and exporting sugars, with mature leaves being major examples.

🌱 Sinks are tissues actively using or storing those sugars, such as:
• Growing roots
• New leaves and shoots
• Developing flowers
• Seeds, when pollination occurs

The plant transports much of this sugar through specialized tissue called the phloem.

As cannabis moves through its life cycle, which tissues demand the most resources can change.

During flowering, developing flowers become important sinks as the plant directs carbohydrates and other resources toward reproduction.

Friday Takeaway:

Fan leaves are not just sitting there collecting light.

They are part of a transportation network that helps supply growing tissues throughout the entire plant.

Cannabis cultivation makes a lot more sense once you start looking at the plant as one connected biological system. 🌱



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