Plant growth lamps play an important role in modern agricultural production, and their key performance indicators directly affect the growth effect of plants.

1. PPE (photon flux efficacy)

PPE (photon flux efficacy) refers to the number of photons emitted by plant supplementary light per unit power per unit time, in μmol/J. The higher the PPE value, the more photons the lamp emits per unit time, thus more effectively promoting plant growth. Generally speaking, the range of PPE values should be above the light compensation point of the plant (PPE value 1.5) and within the light saturation point (PPE value 2.4).

2. PPF (photosynthetic photon flux)

PPF (photosynthetic photon flux) refers to the number of micromoles of photons radiated per second by artificial light sources in the wavelength band of 400-700nm, in μmol/s. PPF indicates the number of photons emitted by the light source, which is essential for the photosynthesis of plants. The higher the PPF value, the more photons the light source can provide per unit time, providing more energy for the photosynthesis of plants.

3. PPFD (Photosynthetic Photon Flux Density)

PPFD (Photosynthetic Photon Flux Density) corresponds to PPF, which is the number of micromoles radiated by the light source per square meter per second, in μmol/m²s. PPFD represents the PPF in a square meter range and is an important indicator for measuring the performance of plant growth lamps. The PPFD value directly affects the light intensity received by the plant, which in turn affects the growth rate and quality of the plant. A PPFD value that is too high may cause photoinhibition of the plant, while a PPFD value that is too low will affect the photosynthesis efficiency. Different plants have different requirements for PPFD. Generally, light-loving plants require higher PPFD values, while shade-tolerant plants can grow at lower PPFD values.

4. Spectral range

• Plants are very sensitive to the wavelength range of 400-700nm in the light radiation spectrum. The light in this wavelength range is called photosynthetically active irradiance (PAR). Different wavelengths of light have different effects on plant growth:

• Blue light (400-500nm): Blue light has a great effect on the early growth of plants, can promote the development of plant roots, increase the strength of plants, and make plants grow more symmetrically and healthier. Blue light can also promote plant synthesis of protein and amino acids, and improve the quality of yield.

• Red light (600-700nm): Red light is the main force of photosynthesis, which can provide power for plant photosynthesis, promote plant photosynthesis and chlorophyll formation, is conducive to stem growth, and can also promote plant flowering.

• Green light (500-600nm): Green light has a certain effect on promoting plant photosynthesis, can penetrate the leaf canopy, and improve overall photosynthesis.

• Far red light (700-800nm): Although far red light is outside the range of photosynthetic active radiation, it also has a certain effect on plant growth. It can stimulate plant cell elongation and affect flowering and seed germination.

5. Comprehensive influence

Key performance indicators such as PPE, PPF, PPFD and spectral range jointly determine the effect of plant growth lamps on plant growth. Lamps with high PPE values can emit more photons per unit time and provide more light energy for plants; suitable PPF and PPFD values can ensure that plants receive sufficient light intensity to meet the needs of photosynthesis; and a reasonable spectral range can provide the most suitable lighting conditions for different growth stages and needs of plants, thereby achieving the best plant growth effect.

When choosing a plant growth lamp, it is necessary to comprehensively consider these performance indicators to meet the growth needs of specific plants and achieve efficient and energy-saving plant cultivation.