The Emerson Effect in Cannabis Growing: Unleashing the Full Potential of Photosynthesis

The Emerson Effect in Cannabis Growing: Unleashing the Full Potential of Photosynthesis

The Emerson Effect in Cannabis Growing: Unleashing the Full Potential of Photosynthesis

The Emerson Effect, a phenomenon discovered by American scientist Dr. Robert Emerson in 1957, has had a profound impact on our understanding of photosynthesis. This discovery has since been applied to the growth of various plants, including cannabis. By understanding and harnessing the power of the Emerson Effect, growers can optimise cannabis cultivation, increasing yield and plant health.

The Science Behind the Emerson Effect

Dr. Emerson discovered that when chlorophyll-a pigments are exposed to two distinct wavelengths of light, photosynthesis rates can be significantly enhanced. Chlorophyll-a is the primary pigment responsible for absorbing light energy and converting it into chemical energy during the process of photosynthesis. It can absorb light at two specific wavelengths, namely red light (around 680 nm) and far-red light (around 700 nm).

When a plant is exposed to only one of these wavelengths, the rate of photosynthesis is limited. However, when both wavelengths are provided simultaneously, the rate of photosynthesis can be dramatically increased. This synergistic relationship is known as the Emerson Effect.

The Emerson Effect in Cannabis Growing

The Emerson Effect can be applied to cannabis cultivation to improve overall plant growth and yield. By providing the optimal light spectrum, growers can maximise the potential of the photosynthetic process, allowing the plants to generate more energy and grow at an accelerated rate.

How to Achieve the Emerson Effect

To harness the power of the Emerson Effect, cannabis growers must ensure their plants receive both red and far-red light simultaneously. There are several ways to achieve this:

Using LED grow lights:

Modern LED grow lights are specifically designed to provide the full spectrum of light required for optimal photosynthesis. Many LED lights have adjustable spectral settings, allowing growers to fine-tune the light spectrum for different stages of plant growth. By selecting a high-quality LED grow light with appropriate red and far-red output, growers can create the optimal conditions for the Emerson Effect.

Supplementing with far-red light:

Some cannabis growers may choose to use traditional grow lights, such as high-pressure sodium (HPS) or metal halide (MH) lamps. While these lights provide adequate red light, they may lack sufficient far-red output to trigger the Emerson Effect. In this case, growers can supplement their existing lighting setup with far-red LEDs or specialised far-red lamps.

Optimising light schedules:

To further enhance the Emerson Effect, growers can adjust their light schedules to mimic natural sunlight. This can be achieved by gradually increasing the proportion of far-red light during the evening hours, simulating the light conditions at sunset. This not only boosts photosynthesis but can also promote faster flowering in cannabis plants.

The Benefits of the Emerson Effect in Cannabis Cultivation

Applying the Emerson Effect in cannabis cultivation can provide several advantages:

Increased growth rates:

By maximising photosynthesis, plants are able to generate more energy, resulting in accelerated growth and development.

Improved yield:

Healthier, more vigorous plants tend to produce larger, denser flowers, leading to higher overall yield.

Faster flowering:

Exposure to far-red light, particularly in the evening, can encourage the transition from the vegetative to the flowering stage, shortening the overall growth cycle.

Enhanced cannabinoid production:

By providing optimal light conditions, growers can also stimulate the production of cannabinoids, such as THC and CBD, and other valuable compounds like terpenes.


The Emerson Effect is a valuable tool for cannabis growers looking to optimise their cultivation practices. By understanding the science behind this phenomenon and implementing the appropriate lighting strategies, growers can enhance photosynthesis, improve plant health, and ultimately achieve higher yields and more potent cannabis products.

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