Most people often want to find out which light source is the best for hydroponic farming or gardening between grow light vs sunlight. Light is a major requirement for growth and development in plants including hydroponically grown plants. Light must be present for photosynthesis to place, and this is a chemical process that occurs in plant leaf cells (chloroplasts) where water reacts with carbon dioxide in the presence of water to form glucose (carbohydrates) and oxygen. The oxygen is released into the atmosphere and the glucose is utilized for plant growth and development needs.

Photosynthesis can take place in the presence of light whether it is grow light or sunlight. However, other factors like quality of light, duration of light exposure etc. should be considered before deciding on which light source (grow light or natural sunlight) is best for your hydroponic plants.

Specific factors that describe the quality of light that is available to hydroponic plants should be considered to determine whether sunlight is sufficient for the plants or if grow lights will be necessary to supplement the sunlight.

Quality of Light

This refers to the spectral distribution of light, which may mean that is the light source providing the adequate wavelengths of light needed to meet the plant needs? The quality of light plants receive is very important to how well plants can grow and develop. Most of hydroponic gardens or farming occur in an enclosed area where exposure to light may be hindered or reduced. The quality of light received by plants can be described based on the following factors: 

Light Intensity: This can be described in simple terms as the concentration of light a plant receives and it can influence things like photosynthesis, stem length, leaf color and flowering. Plants that grow in areas with low light tend to develop spindly stems with light green leaves whereas plants that grow under high light concentration or bright lights tend to do better with shorter stems and large dark green leaves.

Exposure to Light: There may be several things that affect the exposure to light for hydroponic plants that are grown indoors. The distance of the plants from the window or natural light source can affect the intensity or quality of light that plants receive. Other factors like presence of screens, curtains, outside shade, weather etc. will also affect the exposure to light that plants receive.

Duration of Light Exposure: The time during which plants receive light is also very important for their wellbeing. Some plants require long durations of light exposure to grow and develop well, while others just need short or medium durations of light exposure. Supplemental light can be provided using grow lights where light exposure is inadequate.

However, it is important to understand that light exposure for more than 16 hours per day can become harmful to plants just like inadequate exposure to light. 

Type of Plants: You need to understand the light requirements of your hydroponic plants to determine if what they are getting is adequate or not.  Plants are either considered to be low light plants, medium light plants, or high light plants. Low light plants need very minimal or no light in some cases to grow and develop, medium light plants need average amount of light while high light plants need a lot of light to do grow and develop well.

After considering these factors, it should be a lot easier to determine if your plants are receiving adequate light or if you need to supplement the sunlight with grow lights.

Grow Lights

These are artificial lights that are used to supplement or provide adequate light source to meet plant needs. There are different types of grow lights available and some of these include: fluorescent lights, high pressure sodium (HPS) lights, metal halide (MH) and ceramic metal halide (CMH) lights, and light emitting diodes (LED) lights.

Advantages of Grow Lights

• Control: Whereas it is difficult (if not impossible) to control sunlight quality, the various features of grow lights can be controlled to meet the needs of your hydroponic plants.
• Only useful light wavelengths or colors (red and blue): You can install and use specific wavelengths of grow lights that the plants need instead of the full spectrum of wavelength like sunlight.
• Any Location: Grow lights provide the ability to grow plants hydroponically anywhere whether indoors or outdoors.
• Any Season: Plants can be grown hydroponically all year round irrespective of season or time of the year.

Disadvantages of Grow Lights

• Cost: Grow lights can become expensive especially when purchasing large quantities
• Heat: Some grow lights can generate heat which can easily become detrimental to the plants especially if you don’t have a system to regulate or control the heat.
• Complexity: There are instances where you may need to use more than one type of grow light which may make it a little bit more complex in balancing the light requirements.  

Sunlight

Sunlight is an abundant natural resource that plants need and use for their growth and development and it is available in abundance. There are some factors that affect the amount and quality of sunlight that plants may receive and this can be more critical for hydroponic plants. These factors include seasons (times of the year), weather, location of plants (indoor/outdoor), availability of shades, etc.   

Advantages of Sunlight

• Free: Sunlight is a free resource that is available anywhere
• Full Spectrum: Sunlight is available in the full wavelength or spectrum of light. Any plant can absorb any wavelength that is beneficial for it.
• No Adverse Effect: Adverse effects of sunlight are rare

Disadvantages of Sunlight

• Difficult to control: It is a natural resource and may be difficult to control and regulate like artificial grow lights
• It cannot get into enclosed areas which may be a disadvantage for some indoor locations for hydroponic farming or gardening.

Do Plants Grow Better Under Grow Light vs Sunlight

Whether plants grow and thrive better under sunlight or grow light depends on several factors and not just a single factor. For instance, some plants naturally only need little or no light to thrive while others may need significant light to grow and develop well.

The best way to determine which light source may be best for your plants may be to do a test or experiment and evaluate the results. For instance, this experiment was done to determine which light source may be better for plants in terms of plant growth. The results showed that grow lights produced better results in terms of plant growth than sunlight.

There are different factors that influence these results and it is often better to test these factors to understand what works best for your plants.