How to choose a grow light?

Light is crucial for plants' growth and health. However, our green friends don't always have the luxury of basking in long sunny days. That's where artificial light, or grow lights, comes into play.

What are grow lights?

Grow lights are specialized lighting devices designed to emit the specific spectra required by plants, primarily red and blue light. These spectra are essential for plant growth because the blue spectrum facilitates plant nutrition, while the red spectrum accelerates vegetative mass growth. Unlike regular household lights that emit yellow and green spectra, grow lights won't overheat and harm your plants.

Types and advantages of grow lights

There are various types of grow lights available, categorized by the type of bulbs they use:
  • Sodium grow lights: Not suitable for home use due to their brightness and high heat, which can make them explode if they come into contact with water. Disposal is also challenging because of the presence of mercury vapors.
  • Fluorescent grow lights: Also not recommended for use in inhabited areas because they emit a blue spectrum that can be harsh on the eyes. Like sodium lamps, they contain mercury vapor. They are low-powered, not suitable for all plants, and less effective at low temperatures.
  • Induction grow lights: Similar to fluorescent lamps but designed without internal bulbs. These lamps tend to be expensive.
  • LED grow lights: These lights have a long lifespan, consume less energy, and are suitable for household use. They produce minimal heat and pose no harm to people or animals. The only drawback is that they can be relatively more expensive.
For household applications, LED grow lights are the preferred choice due to their numerous advantages:
  • Compact and suitable for home use.
  • Adjustable.
  • Compatible with regular household fixtures, such as table lamps.
  • Some models offer a spectrum selection.
  • Available in various shapes, allowing you to choose the one that suits your needs.

Selecting a Grow Light by Spectrum

Grow lights come with different spectra:
  • Bicolor: These lights have pronounced peaks in the blue and red spectra and are effective while being relatively affordable.
  • Full spectrum: These lights have broad peaks in the blue and red spectra and closely mimic natural sunlight. They are suitable for most plants.
  • Multispectrum: These lamps combine red, blue, warm white, and far-red light. They not only maintain plant health but also stimulate flowering and fruiting, making them suitable for growing plants in conditions of limited sunlight.
To choose the right lamp, it's essential to understand which spectrum is appropriate for your specific needs:
  • Ultraviolet (280-400 nm): Stimulates vegetative growth and strengthens plants.
  • Blue (400-520 nm): Promotes seed germination, seedling growth, and root system development, and contributes to chlorophyll accumulation in leaves.
  • Green (520-600 nm): Aids in chlorophyll accumulation and participates in photosynthesis.
  • Orange (600-620 nm): Stimulates photosynthesis and beta-carotene production.
  • Red and far-red (620-870 nm): Promote flowering and fruit formation.
Most household applications use bicolor lamps, so pay close attention to the spectrum's wavelength. Ideally, the blue spectrum should have a wavelength of 440-450 nm, and the red spectrum should measure 650-660 nm. This information is typically available on the packaging.

Actual and rated power

Grow lights come in various wattages, but it's crucial to differentiate between actual and rated power. Rated power is the maximum limit at which diodes operate, but they won't last long at this level. Therefore, lamps typically work at half power. For example, a 3W grow light provides an actual power output of 1½W. Manufacturers often specify this information, so take it into account.
For household use, grow lights with power ranging from 36W to 80W are suitable.

Shapes of LED grow lights

The choice of grow light shape depends on the number of plants and the container's configuration. Shapes include:
  • Spot lights: Compact and cost-effective.
  • Linear lights: Ideal for illuminating multiple plants, providing even distribution of light.
  • LED strips: Easy to use and install, taking up minimal space and lighting a large area.
  • Full spectrum lamps: Highly efficient and adjustable, but they tend to be larger and pricier.
Ensure that you select the grow light shape that best suits your specific needs and growing environment.