Artificial Grow Light VS Sunlight, Which is Better

There is no doubt about the importance of light for plants. Light is one of the leading sources of photosynthesis, which is critical for plant growth. Nowadays, sunlight and artificial grow light are frequently utilized for growing. Sunlight is natural, and it is the common light source for plants. With advanced technology, LED grow lights are widely used in both commercial and home growing due to their highly efficient sunlight mimicry and custom spectrum.

Regardless of artificial light or sunlight, there are three basic factors for calculating lighting efficiency, lighting intensity (total amount of light plants receive), duration (time or periods of light that plants receive during 24 hours), and quality of light (wavelength of light). But you also consider the total cost while they use artificial lights. When it comes to the selection of light sources, you may scratch your head and wonder which light source is better. Let's talk about the comparison between artificial grow lights and sunlight for plant growth.

Sunlight

Benefits

The key benefit of sunlight is that it is free and abundant. The sun has been giving off sunlight for a long time, and it is not likely to stop emission. Natural sunlight exists in the environment and humans do not need to pay for it. Everyone can utilize sunlight by simply placing their plants outdoors under the sun, or indoors near the windows.

Secondly, sunlight provides all wavelengths that plants need through the whole life cycle from germination to fruiting. It is well known that blue light improves plant growth, while red light promotes flowering and fruiting. In fact, sunlight emits more than blue light and red light. Light in other wavelengths, such as green light and UV light is also involved in sunlight. Plants absorb the most helpful wavelengths freely to boost their growth.

Moreover, sunlight is powerful and of high intensity. Research showed that it required at least 13 hours for artificial grow light to reach the amount of energy delivered by sunlight in 6 hours. In other words, sunlight has a stronger energy output, which can promote plant growth under certain conditions.

Limitations

Although it is claimed that sunlight is best for plant growth, it also has limitations. First, the duration of sunlight is not controllable. Sunlight is not available consistently in the same location. In contrast, it is moving from one place to another continuously. To gain adequate light and enough periods of lighting, you may need to move your plants to follow the movement of sunlight.

Furthermore, the duration of sunlight is limited by weather conditions and season changes. Under bad weather like rain, plants cannot receive sunlight at all. In winter, daytime is much shorter than night, which means sunlight may be inadequate for plants. Most plants react by flowering and fruiting according to the time of light they receive per day. The growing stage of plants is not controllable due to the limitation of sunlight duration. Therefore, year-round production is not achievable under solely sunlight conditions.

Another limitation of sunlight is that it is natural and customization is not allowed. Sunlight provides the whole spectrum all at once for plants. Though plants can absorb the wavelengths that are beneficial for their growth, they also bear the negative part of sunlight. Moreover, sunlight may be too powerful to grow for plants in various species and growing stages. The strong sunlight may kill the plant due to the high lighting intensity.

Artificial grow light

Benefits

The major benefit of artificial grow light is that it is controllable, which is absolutely impossible with sunlight. Light spectrum, duration, and the location of artificial grow light are all controllable according to what the plants need. Light requirements of plants in different species and growing stages are varied. Many LED grow light manufacturers such as Atop provide customized spectrum with nearly endless wavelength combinations to meet various needs. With an optimal lighting spectrum, maximized plant growth and production can be achieved.

Additionally, artificial grow light will not change with the weather or season. No matter the outdoor condition, artificial grow light can keep lighting the plants, creating longer light duration and year-round production. Plants are able to absorb adequate light during dark winter or bad weather conditions. Flowering and fruiting of most plants (long-day plants) are regulated by the light duration. Extended light duration induces flowering and fruiting, allowing earlier arrival in the market and then bringing more profits for growers.

The last benefit of artificial grow light is the adjustable location. Growers can place the artificial grow light closer or further to the plants freely. The location of the artificial grow light is changed with the movement of plants, which is completely different from sunlight.

Limitations

Unfortunately, artificial grow light is not as powerful as sunlight. Artificial grow light is manufactured to mimic sunlight. As of now, artificial grow light is not capable of replacing sunlight because of the lower lighting intensity. As mentioned before, lighting efficiency is calculated by light intensity, duration, and quality. Artificial grow light provides light in the PAR range which is beneficial to photosynthesis. Although artificial grow light allows light duration and quality customization, the light intensity of artificial grow light and sunlight is not comparable. Artificial grow light requires more time to deliver the same energy as sunlight.

Another drawback of artificial grow light is the high cost compared to free sunlight. Some entry-level artificial grow lights are not expensive, but the price may increase rapidly if you would like the customized one. Except for the cost of the grow light itself, artificial grow light also consumes energy and needs maintenance. Artificial grow lights are kept on for at least 14 hours in indoor vertical farms for growing long-day plants. The electricity bill can be striking. If there is something wrong with the artificial grow light, maintenance is required. But many of the components are not recyclable. Thus, artificial grow light is of high cost compared with sunlight.

Artificial grow light or sunlight, which is better

Generally, sunlight is natural, free, and powerful. It is best for plant growth, but light duration is limited by weather, season, and location. Artificial grow light is of high cost and lower light intensity, but the light quality and duration are controllable. The answer to the question of which light source is better for plant growth, artificial grow light or sunlight, depends on the plant species, season, and location. Thus, the answer cannot be one size fits all.

Many flowering vegetables like tomatoes and cucumbers are full-sun plants while others are low-light plants. Long time exposure to the light with higher intensity helps full sun plants grow better. If sunlight is inadequate, artificial grow light can add value. For indoor home growing, just place the plants near the window if there is abundant sunlight. If not, artificial grow light is an ideal option for supplementing light for plants during cloudy days or winter. For commercial indoor growing, however, artificial grow light is irreducible. Artificial grow light plays an important role throughout the whole production, regulating the morphology and growing stages of plants. One of the most representative applications is the vertical farm, which utilizes artificial grow light as the sole light source. Thanks to artificial grow light, higher yield in less land is achievable.