What Is the PPF Output of the Koray GK-200W and How Does It Translate to Real-World PPFD?

When evaluating a greenhouse grow light, the two most important metrics are PPF (photosynthetic photon flux) and PPFD (photosynthetic photon flux density). PPF tells you the total number of photosynthetic photons the fixture produces per second, while PPFD tells you how many of those photons actually reach a specific point on the plant canopy. In this article, we break down the PPF output of the Koray GK-200W and explain what it means for your greenhouse operation.

What Is PPF and Why Does It Matter?

PPF measures the total amount of light in the 400 to 700 nanometer photosynthetically active radiation (PAR) range that a fixture emits in all directions, expressed in micromoles per second (umol/s). Think of it as the total “volume” of plant-usable light a fixture generates. A higher PPF means more photons are available to drive photosynthesis, but it doesn’t tell you where those photons go.

That’s where PPFD comes in. PPFD measures the density of photons arriving at a specific surface, expressed in micromoles per square meter per second (umol/m2/s). For greenhouse growers, PPFD at the canopy level is the number that directly determines crop growth rate, yield, and quality.

GK-200W PPF Output by Spectrum

The Koray GK-200W is available in multiple spectrum configurations, each with a slightly different PPF output due to variations in LED efficiency across wavelengths.

The V3 high-efficacy spectrum achieves 2.8 umol/J, producing approximately 560 umol/s from its 200W power draw. This spectrum prioritizes photosynthetic efficiency, making it ideal for growers who want maximum photon output per kilowatt-hour of electricity.

The F175 full-spectrum version delivers a balanced output across the entire PAR range, with a slightly lower PPF of approximately 540 umol/s. While the raw PPF is marginally lower, the F175 spectrum provides superior color rendering (Ra greater than 85) and a more natural light appearance, which is beneficial in greenhouses open to visitors or where worker comfort matters.

The K6 spectrum, optimized for flowering and fruiting with enhanced red wavelengths, produces approximately 520 umol/s. The additional red photons in the 630 to 660 nanometer range are particularly efficient at driving photosystem II activity, so the effective photosynthetic impact may exceed what the raw PPF number suggests.

From PPF to PPFD: Understanding the Conversion

The relationship between PPF and PPFD depends on three factors: mounting height, beam angle, and optical design. A fixture with high PPF but a narrow beam angle will produce very high PPFD in a small area, while the same PPF spread over a wider area results in lower PPFD but better uniformity.

The GK-200W uses Koray’s secondary optical system with a 120-degree beam angle to distribute its photons evenly. At a mounting height of 1.0 meter, the center PPFD reaches approximately 500 umol/m2/s, while the average PPFD over a 2.5-meter diameter circle is approximately 380 umol/m2/s. At 1.5 meters, the center PPFD drops to approximately 350 umol/m2/s with an average of 250 umol/m2/s over a 3-meter diameter. At 2.0 meters, the center PPFD is approximately 220 umol/m2/s with an average above 160 umol/m2/s over a 4-meter diameter.

PPFD Uniformity: The Koray Advantage

One of the most significant advantages of the GK-200W over competing fixtures is its PPFD uniformity. Traditional LED grow lights with bare chips or simple reflectors create a bright center hotspot that can cause light stress or photoinhibition in the plants directly below, while the edges of the coverage area receive insufficient light.

Koray’s secondary optical system uses precision-molded lenses to reshape the light distribution from each LED package. The result is a smooth, bell-curve PPFD profile with no sharp center peak and minimal edge falloff. The uniformity ratio (minimum PPFD divided by average PPFD) exceeds 0.7 across the recommended coverage area, meaning every plant in the coverage zone receives at least 70 percent of the average light level.

How Many GK-200W Fixtures Do You Need?

The number of fixtures depends on your target DLI (daily light integral) and the crop you’re growing. For example, tomatoes require a DLI of 20 to 30 mol/m2/day for optimal fruiting. If your greenhouse receives 8 mol/m2/day of natural sunlight in winter and you want to supplement to 20 mol/m2/day with 16 hours of artificial lighting, you need the fixtures to deliver an additional 12 mol over 16 hours, which equals an average PPFD of 208 umol/m2/s.

With a single GK-200W (V3 spectrum) delivering an average PPFD of approximately 250 umol/m2/s at 1.5 meters height over a 3-meter diameter area, you would need approximately one fixture per 7 square meters to achieve this supplemental DLI target. For a 1,000 square meter greenhouse, that translates to roughly 140 to 150 fixtures, depending on layout and overlap.

Comparing GK-200W PPF to Competitors

Many 200W class LED grow lights on the market deliver PPF outputs in the range of 350 to 450 umol/s, corresponding to efficacies of 1.75 to 2.25 umol/J. The GK-200W’s V3 spectrum at 2.8 umol/J and 560 umol/s significantly outperforms these alternatives. When comparing fixtures, always normalize by both wattage and efficacy, and pay attention to whether the manufacturer reports PPF or just center PPFD at a convenient distance.

Does PPF Decline Over Time?

All LEDs experience lumen depreciation over their operating life. The GK-200W uses high-quality LED packages rated for L70 at 50,000 hours, meaning the PPF output will remain above 70 percent of its initial value after more than 13 years of 10-hour daily operation. In practice, most growers will not need to replace fixtures or compensate for significant output loss within the first decade.

Measuring PPF and PPFD Yourself

While manufacturer specifications are useful, serious greenhouse operators should verify light levels with a calibrated PAR meter. Take measurements at a grid of points across the coverage area at canopy height, and calculate both the center and average PPFD. This data allows you to fine-tune fixture spacing, mounting height, and dimming settings to achieve your target DLI with maximum efficiency.

The Koray GK-200W combines industry-leading PPF efficacy, uniform optical distribution, and robust greenhouse-rated construction to deliver measurable photosynthetic performance. Whether you’re supplementing natural light in a tomato greenhouse or providing sole-source lighting for a vertical nursery, the GK-200W provides the photon output your crops need to thrive.

Koray Lighting, established in 2009 in Zhongshan, Guangdong, holds over 200 patents in LED lighting technology. The company’s 2,800 square meter testing facility ensures every product meets rigorous performance standards before shipment. All GK-200W fixtures carry CE, RoHS, and FCC certifications.