There is a process that drives everything else. Without it, no growth, no nutrients, no yield. No red onion with quercetin, no tomato with lycopene, no carrot with beta-carotene. No Brix value to speak of.
This process is called photosynthesis. And for most plants in the world, it operates far below its potential.
The reason is surprisingly simple—and so is the solution.
What Photosynthesis Really Is
The CO₂ Problem — Why Plants Are Chronically Undersupplied
Here lies the crucial detail that most people don't know.
Air contains only 0.04 percent CO₂ — that's just 400 parts per million. This is extremely low. For a maximum photosynthetic rate, the plant would actually need a CO₂ concentration of 0.1 to 1.0 percent inside the leaf — that is, twenty-five times what the atmosphere provides.
This means: under natural conditions, plants are CO₂-limited (their performance is restricted by too little CO₂). They cannot fully exploit their photosynthetic potential because the raw material CO₂ is simply not available in sufficient quantities.
In addition, there is a fundamental conflict. The plant absorbs CO₂ through its stomata (leaf pores — tiny openings on the leaf surface that open and close). But open stomata simultaneously lose water through evaporation. Under drought stress, the plant therefore closes its stomata to conserve water — and thereby cuts itself off from CO₂ supply. Photosynthesis collapses. The Brix value drops. The plant weakens itself at the moment when stress is greatest.
This is not a minor issue. It is the core conflict of plant physiology — and it occurs daily in every plant in the world.
What Happens When Photosynthesis Stalls
A plant that receives too little CO₂ operates on a low flame. What that specifically means:
Less glucose is produced.
This means less energy for growth and cell division. Roots remain shallower. Biomass remains lower.
Fewer building materials for cell walls.
Calcium is the main building block of stable cell walls — but calcium can only be effectively incorporated into cell walls if enough energy from photosynthesis is available. Thin cell walls are the gateway for fungal diseases and pests.
Fewer secondary plant compounds.
Quercetin, lycopene, beta-carotene, allicin — all these substances are only formed if the plant has an energy surplus from photosynthesis. A plant running on a low flame produces the minimum — not the maximum.
Lower Brix value.
The Brix value measures the density of the plant sap — that is, how many dissolved solids it contains. A plant that performs little photosynthesis has a low Brix value. It tastes less, nourishes less, lasts less long.
Higher susceptibility to pests.
Francis Chaboussou already documented in 1969 that insects and fungi preferentially attack plants with incomplete protein synthesis (protein formation — when the plant cannot form complete proteins) — i.e., plants that perform too little photosynthesis. A plant with a high Brix value (the measurement for nutrient density in the plant sap) is simply uninteresting for sucking insects like aphids — its sap contains too many complex compounds that their simple digestive system cannot process.
The Direct Route — Bringing CO₂ into the Leaf
Here lies the basic idea behind Grünkraft Calcium as a foliar fertilizer. And no one has explained it more clearly than Dr. Peter Ost:
"GRÜNKRAFT is a CO₂ fertilizer. The optimal CO₂ content should be between 0.1 and 1.0 vol% for high photosynthetic activity. Air has only 0.03 vol%, which is why plants cannot utilize their optimal growth potential. GRÜNKRAFT naturally increases the CO₂ content in the plant, thus helping the plant breathe."
The solution is elegant. Tribomechanically activated calcite with zeolite is sprayed onto the leaf. The particles are smaller than 10 micrometers — stomata-permeable (small enough to penetrate the leaf interior through the leaf pores). They penetrate directly into the leaf tissue through the leaf pores.
There, the calcium carbonate disintegrates:
CaCO₃ → CaO + CO₂
The released CO₂ immediately enters photosynthesis. Not at some point. Not after detours via soil and root. Directly. The plant gets the raw material it needs for maximum photosynthesis — regardless of what is in the air outside and regardless of whether the stomata are closed due to drought stress.
The CO₂ in calcium carbonate is reversibly bound — this means: it is not released all at once, but precisely when the plant cell needs it. The calcium carbonate gradually releases the CO₂ — controlled by the conditions inside the leaf. At high photosynthetic activity, more CO₂ is released. At lower activity, less. The plant therefore does not receive a one-time CO₂ boost — it receives a continuous, needs-based supply. This is fundamentally different from simply supplying CO₂-richer air from outside.
This is the bypass. CO₂ directly into the heart of the leaf — exactly as much as the plant needs at any moment.
What Happens Simultaneously — The Calcium Effect
The released calcium oxide is no less important than the CO₂. It performs four functions simultaneously:
Strengthen cell walls. Calcium is the most important building block of stable, dense cell walls. Strong cell walls mean fewer entry points for fungal spores — less botrytis, less powdery mildew, less scab. A plant well supplied with calcium protects itself.
Regulate stomata. Calcium controls the opening and closing mechanism of the leaf pores. Well-regulated stomata open precisely in light and close efficiently in drought — the plant loses less water and still absorbs enough CO₂.
Improve nitrogen uptake. Calcium stimulates ammonium absorption (the uptake of nitrogen in its usable form for plants) — the plant can absorb and process nitrogen more efficiently. This explains the darker, more intense green of treated leaves — they are better supplied with nitrogen, although no additional nitrogen fertilizer was applied.
Activate defense mechanisms. Calcium triggers a cascade (a chain of consecutive reactions) of defense reactions in the plant — from the formation of pathogenesis-related proteins (special defense proteins against pathogens) to the activation of enzymes (protein molecules that control chemical processes) that break down fungal spores.
What Zeolite additionally achieves
The zeolite in the product also contributes to the photosynthesis effect — in a way that Dr. Peter Ost particularly emphasizes:
"The zeolite particles can capture sunlight more strongly on the leaf and thus help to make photosynthesis more active."
The ultrafine silicate particles (finest mineral particles from the zeolite) on the leaf surface act like tiny mirrors that better distribute and guide the incoming light into the leaf. More light on more chloroplasts (the green cell organelles where photosynthesis takes place) means more photosynthesis — an additional amplifying effect.
At the same time, the silicon from the zeolite activates plant's own defense enzymes — superoxide dismutase, catalase, and peroxidase (enzymes that neutralize harmful free radicals) — which neutralize free radicals (aggressive molecules that damage cells) and protect the plant against oxidative stress (cell damage caused by these aggressive molecules).
And then there's the physical protective effect: The silicate particles on the leaf surface look like small shards of glass under the microscope. Insects with tactile organs in their legs find this unpleasant and avoid the plant. The finest particles disturb and block the respiratory organs of mites and aphids. This is not a chemical repellent (a deterrent that drives away insects) — it is physics.
What Becomes Measurable — The Evidence in the Brix Value
The increased photosynthetic activity after treatment with Grünkraft Calcium is not just theoretical — it is measurable. The Brix value of the plant sap measurably increases within 2 to 3 days after treatment.
Why is that?
Because more photosynthesis produces more glucose — and glucose is one of the main components of the plant sap that the refractometer (an optical measuring device that measures the density of liquids) measures. A higher Brix value directly indicates: this plant is performing intensive photosynthesis. It is well supplied. It forms secondary plant compounds.
According to the Reams reference table: below 7 °Brix, a plant is susceptible to all pathogens. From 14 °Brix, insects can no longer tolerate the plant sap. This is no coincidence — it is the direct consequence of a plant that performs intensive photosynthesis and thus builds up its full immune system.
The nutrient-rich tomato with 12 °Brix. The red onion with 10 °Brix full of quercetin. The carrot with deep orange full of beta-carotene. The garlic that smells intensely because it is full of allicin. They are all the result of a plant that had enough CO₂ to fully perform its photosynthesis.
From Plant to Plate — The Crucial Connection
Here the circle closes. And it is a connection that is little known to the public, although it is scientifically well documented.
The secondary plant compounds that we find in nutrient-rich foods — quercetin, lycopene, beta-carotene, allicin, sulforaphane, anthocyanins — all arise from photosynthesis energy. They are the surplus that a plant produces when it has enough CO₂ and can perform intensive photosynthesis.
A plant that is chronically CO₂-limited forms the minimum of secondary plant compounds. A plant that is optimally supplied with CO₂ forms the maximum.
The British McCance and Widdowson Study, which documented the decline in minerals in food between 1940 and 1991, is obvious: Not only have soils become poorer — the photosynthesis of plants on these soils is also less efficient, because stressed plants on poor soils close their stomata more often and thus absorb less CO₂.
More photosynthesis is therefore not only an agronomic (relating to agriculture and crop cultivation) goal. It is a nutritional health goal. It is the path from empty calories to real nutrient density.
Why the tribomechanical grinding process is key
Not every calcite can achieve this effect. The difference lies in the manufacturing process.
Conventionally ground calcite — as it is sometimes scattered on fields — is too coarse for the stomata. Dr. Peter Ost explains it with an image that we always remember:
"You can eat a hamburger because your mouth and the size of the hamburger roughly match. But if you had a hamburger the size of a soccer ball, it would not be possible to eat it. The lime that is sometimes conventionally scattered on the field is on the field, is chemically detectable, but is not available to the plants because it is too coarse."
In the tribomechanical process (an activation process in which mineral particles collide at high speed), calcite particles collide at high speed — up to three collisions per millisecond. The particles are split without destroying the internal crystal lattice structure (the ordered internal structure of the mineral that determines its properties). The result is particles under 10 micrometers that are electrostatically charged by the tribomechanical process.
This electrostatic charge has two effects: The particles adhere optimally to the leaf surface and are not blown away by the next wind. And they are actively drawn through the stomata into the leaf interior by the charge.
This is the difference between a product that is chemically detectable on the leaf — and one that actually reaches the plant.
Why Leaf Gloss is the Visible Proof
There is a visible sign that shows whether a plant is truly performing intensive photosynthesis: leaf gloss.
John Kempf — one of the leading figures in regenerative agriculture — has described what leaf gloss means physiologically (at the level of plant physiology — i.e., how the plant body functions): Only when a plant achieves an energy surplus through photosynthesis does it store this as fats in the cell walls and as a waxy cuticle (a natural wax layer on the leaf surface) on the leaf surface. This wax film — recognizable by the leaf gloss — is also a natural protective layer against pests and fungi.
In other words: a shiny leaf is a leaf that performs more photosynthesis than it needs for pure survival. It has a surplus. It forms protection. It is healthy.
Treated plants show this leaf gloss significantly earlier and more intensely than untreated ones. This is not a cosmetic effect. It is the visible signal of a plant operating at full capacity.
The Chain from Photosynthesis to Nutrient-Rich Food
Healthy soil → active soil microbiome (the community of all microorganisms in the soil — bacteria, fungi, protozoa) → strong roots → good mineral supply → intensive photosynthesis → more glucose → more secondary plant compounds → higher Brix value → nutrient-rich food → healthy person.
Grünkraft Calcium intervenes directly in the middle of this chain — in photosynthesis. It is the shortest path from mineral to plant vitality. Directly through the leaf. Without detours.
And because photosynthesis is the engine that drives everything else, an intervention here affects all other links in the chain — both up and down.
Sources: Dr. Peter Ost, quote on tribomechanically activated calcite and zeolite as foliar fertilizer | Francis Chaboussou, Plant Health and Pest Infestation 1969 | John Kempf, Plant Health Pyramid and Leaf Gloss as a Quality Feature | Dr. Carey Reams, Brix Reference Tables | McCance & Widdowson, Mineral Decline in British Foods 1940–1991
