When growing plants indoors – either commercially or just in an indoor garden or grow room – you need to have the right type of light to meet your growing needs. Regularly, growers decide between a few different lighting options, such as LEDs, fluorescent lights, metal halide options, or high-pressure sodium grow lights. Today we’ll be discussing LEDs vs. fluorescent grow lights, which is a common question for growers. There are many options out there, and you’ll typically find some pretty conflicting information on which option is best.
In this article, we’re going through the definitions of LED bulbs and fluorescent bulbs, walk you through some of the best grow lights in each category and then finish off with our take on the best type of grow light for your needs. In the battle between LED and fluorescent lighting, we have the information you need to get started!
Read More: LED Grow Lights Vs. HPS
Considerations When Choosing A Grow Light
When it comes to grow lights, there are three main factors to consider: the color of the light, the energy cost of the fixtures, and the intensity of the light. Let’s start by knowing the needs of your plants before we look at the LED vs. fluorescent lights.
The Light’s Color
We all know that plants need light to thrive, but have you ever considered how the hue of light influences plant growth?
The sun produces the full visible light spectrum, including red, orange, yellow, green, blue, indigo, and violet. This is referred to as full-spectrum or white light.
Most indoor plants flourish in full-spectrum bulbs, which produce a balance of cool and warm light that simulates (or at least tries to mirror) the sun. Seedlings, houseplants, culinary herbs, and a variety of other plants thrive in this full-spectrum light.
Blue light, in general, promotes the development of leaves and stems. Red light promotes flower development, making it crucial for fruit-bearing plants. However, there is a wealth of information available on the unique advantages of red and blue lights. Some of it is also deceptive.
A good video on frequent misunderstandings about the color spectrum, notably red and blue light, may be found here:
Par vs. Lumens
It’s easy to overlook the fact that plants and humans receive light in quite different ways. Humans use photopic vision to sense color. Photosynthetic active radiation (PAR) is the light wavelengths that drive photosynthesis in plants. An excellent article on the differences between PAR and lumens can be found here.
PPF (Photosynthetic Photon Flux) refers to the total amount of light produced per second by an LED, fluorescent, or other light sources. This is what we refer to as the intensity of the grow light. The unit of measurement is micromoles per second (umol/s).
What is the PAR value of the light?
The wavelengths of light that stimulate photosynthesis in plants are PAR (photosynthetic active radiation). We utilize Photosynthetic Photon Flux to calculate the amount of PAR produced by a system per second (PPF). PPF does not indicate how much of the measured light reaches the plants, but it is essential to know if you want to determine how efficient a lighting system produces PAR.
What Percentage of PAR Does Your Plant Get?
The photosynthetic photon flux density is used to measure the quantity of instantaneous PAR that travels from your fixture to your plants (PPFD). This is a measurement of the PAR emitted by the lighting fixture at the plant.
Intensity on the Whole
Light intensity refers to the power or amount of light generated by a specific lighting source. It is a wavelength-weighted power measurement of a light source.
The lighting source determines the light intensity, and there are high and low light intensity fixtures, lamps, light bars, and bulbs available.
Different light intensities serve other functions when it comes to indoor gardening. Young plants, for example, require less light than vegetative and blooming plants.
What Is An LED Light?
LED stands for “light-emitting diodes” and is one of the main types of grow lights on the market. LED grow lights are energy-efficient luminaires that produce artificial light for growing plants. LED fixtures work by combining two semiconductor materials: one charged positively (protons) and one charged negatively (electrons). When these two particles collide, energy is released in the form of a photon. The hue of the light is determined by the amount of energy released. The light is then focused and emitted in a precise direction.
Here’s a quick demonstration of how LED lighting works:
Previously, LEDs have been considered costly alternatives to other grow lights, but since the 1990s, they’ve evolved significantly and are increasingly considered potential alternatives to traditional greenhouse lighting sources.
That said, it wasn’t until recently that researchers could increase the emission power of LEDs and make them emit white light (full-spectrum light).
Traditional incandescent, fluorescent, or HPS lamps use more energy and produce far more heat than this new LED type. LEDs are likewise built entirely of solid parts and can be made relatively tiny for compact growing.
They may also be modified in many situations, allowing you to emit any color of visible light on the spectrum. You can alter the spectrum with this smart lighting to better match the needs of your plants.
Benefits Of LED Grow Lights
- Longer lifespan than most lighting options
- Produces less heat
- Uses less energy
- Emits full-spectrum light
- More compact growing options
- Typically easy to customize
- Becoming more affordable each year
- State and federal rebates available in some situations
Cons Of LED Grow Lights
- More expensive upfront than a lot of lights
- The blue light generated can harm your retinas
- Light burn on plant leaves is a potential risk with this type of indoor lighting
What Are The Best LED Grow Lights?
What works well for one grower might not work well for another. As a result, we’ve compiled a list of the top LED grow lights on the market, organized by use and price.
For this comparison, we used MIGRO data. If there’s any doubt about MIGRO’s objectivity, given that they market their own systems, we might remember that their own products are ranked 4th for best value by PAR production per dollar and 2nd for best value after three years.
Before taxes and shipping, the figure below compares the cost of the light to the PAR output (mols/sec useable PPF) split per dollar.
Here’s a comparison price of the products available on Amazon.
The figure below shows the initial cost of the LED fixture versus the cost of running it with electricity for three years at 750mols/m2/sec. What’s notable about this graph is that several of the more expensive units, many of which were ranked lower in the previous chart, gain ground in this comparison. The operating expenses of higher-quality and more efficient fixtures are often cheaper, bridging the gap with some of these initially more affordable solutions.
What Is An LED Lamp: An LED lamp consists of an LED mounted on a heat sink, with a power supply and directional lenses.
What Is A Fluorescent Light?
A fluorescent light or fluorescent lamp creates light through the fluorescence of a phosphor coating. It is a cooler and more efficient option than incandescent lamps and is more affordable than LEDs.
A fluorescent lamp is made out of a glass tube that is filled with argon and mercury vapor. At each end, metal electrodes are covered with an alkaline earth oxide that emits electrons. The gas between the electrodes is ionized and emits UV light when the current travels across it. Phosphors, chemicals that absorb UV radiation and fluoresce, are coated on the inside of the tube. As this happens, the energy is released as visible light.
Two Types Of Fluorescent Lights
Typically, fluorescent grow lights are divided into fluorescent tubes and compact fluorescent lights (also known as CFL).
CFL grow lights are different from conventional CFLs in that they are larger, have higher wattages, and emit a wider spectrum of light. Fluorescent tube grow lights are available in various sizes and types. Still, the T5 diameter high-output (HO) grow lights, which provide roughly twice as much light as conventional fluorescent tubes, are typically considered the best to use. Built-in reflectors and ballasts are common in fluorescent grow light fixtures, giving them a slim profile.
Best Fluorescent Grow Lights
In the fluorescent category, there are two primary types of lights: t5 grow lights and CFL lights.
Of the t5 grow lights, here are some of our favorite options for this year:
Benefits Of A Fluorescent Light
- Affordable – They are more affordable than incandescent bulbs and LEDs
- Efficient – While not as efficient as LEDs, they are much more efficient than HID (about 50% less energy), meaning you are using less power and saving more money than other options
- Great for seed starting – one of the primary uses for t5 fluorescent lights is seed starting
- Customizable – There are many fluorescent lights with different hues, whether you’re looking for vegetative growth or flower production. While it’s not as easy to customize these lights as it is for LEDs, it’s still a straightforward option.
Cons Of A Fluorescent Light
- They don’t last as long as LEDs
- If broken, the mercury inside can cause serious health hazards
- They don’t typically last as long as LEDs
- They aren’t as energy efficient as LEDs
When Should You Use A Fluorescent Grow Light?
Fluorescent lights are great for plants that require low to medium amounts of light, such as sansevieria and golden pothos. They are also commonly used to start vegetables from seed indoors. Long, tube-like bulbs in various diameters, including T5, T8, and T12, are widely used in these lights.
Can You Use Regular Fluorescent Lights To Grow Plants?
While it may seem like an easy fix, most standard lighting will not work well for indoor plants. Normal indoor illumination has minimal effect on photosynthesis, but fluorescent lighting put close to the tops of the plants can aid in this vital plant function. The best option is to purchase a grow light designed explicitly for maximizing photosynthesis.
LED Vs. Fluorescent Grow Lights: Comparison
LED lights emit very little radiant heat (about 11 percent), whereas fluorescent lights produce greater radiant heat (approximately 30 percent). In other words, in most cases, LEDs do not produce as much heat as fluorescent grow light bulbs.
Having said that, there are various conditions in which indoor gardeners might desire their lights to generate heat.
If you’re growing a plant that requires a higher leaf surface temperature, consider radiant heat while selecting a light source. In that case, a fluorescent lamp may be a viable solution. However, if heat is a top priority, an HPS or other HID lighting fixture may be the best option.
Most Affordable Upfront
Fluorescent lights are often less expensive to purchase than LED lights. LED technology, on the other hand, has been closing the gap since the early 1990s. When it comes to fluorescent vs. LED, fluorescents win for now. But in the long run, LEDs produce more light at a more efficient price, meaning they’re often cheaper in the long run.
Most Energy Efficient
Fluorescent lights and incandescent bulbs are inefficient compared to LED bulbs.
When first introduced, CFLs were praised for their 25 percent to 35 percent energy savings over incandescent bulbs.
But once again, LEDs have raised the stakes. When comparing CFL and LED bulbs, LEDs with an ENERGY STAR® rating use 75% less energy.
Fun Fact About LED Efficiency: According to Energy.gov, widespread usage of LEDs could save around 348 TWh of electricity by 2027. At today’s electricity pricing, that’s the annual electrical production of 44 1,000-megawatt electric power plants, representing a savings of more than $30 billion.
Easiest To Customize
One of the most remarkable aspects of LEDs is how easy it is to tailor the light for individual plant requirements. These diodes can be programmed to emit light at a particular wavelength in the photosynthetic spectrum (visible and non-visible). This means you may adjust the number of blue or red diodes in your lights.
In most situations, you are not able to customize fluorescent lights – at least not easily. The reason for this is that the process of creating a fluorescent lamp is a chemical one. Once the system is set in place, changing it can be tricky. That’s not to say that there isn’t variety in fluorescent light, but customizing that light – at least to the extent that LEDs can be customized – is not typically an option.
While intact, fluorescent tubes are entirely safe. But if you break a bulb in this lighting system, there is some opportunity for danger. Fluorescent tubes, including CFL bulbs, have a little bit of mercury gas in them. This gas is toxic to humans and can adversely affect our kidneys, lungs, and nervous system.
If you break a fluorescent grow light, start by removing all pets and people from the room. Open a window and turn off any heating or air-conditioning system so that the toxic material isn’t distributed throughout your home. You need to let the room with the broken bulb air out for at least 10 minutes (but preferably several hours) before you return to clean up. For the complete list of instructions on what to do if a fluorescent bulb breaks, start with the EPA guidelines.
On the other hand, LEDs do not contain mercury, so they are a safer option in that regard. There is some (mostly unwarranted) concern that LEDs are harmful to the human eye, specifically the blue light produced. While staring directly at the light for long periods could cause damage to your retinas, it shouldn’t be a concern for most growers.
Best Color For Plant Growth
Plants require full-spectrum light to thrive, and this is available with LEDs. This, however, is not always the case with a single fluorescent light, which is traditionally one or the other. If you just use cool light, your plants will grow tall and spindly, whereas if you only use warm light, your plants could grow short and bushy with no blossoms.
Indoor gardeners have long used a two-tube fluorescent fixture with one cold and one warm bulb or a full-spectrum fluorescent tube that emits warm and cool light to counteract this impact.
Individual warm and cold LEDs have been combined into a single bulb by LED producers, allowing it to emit a good light balance.
What Is a full-spectrum grow light: this growing option is a light that emits a spectrum similar to natural sunlight, including red light, green light, UV radiation, red light, and blue light.
Which Option Lasts Longer?
The average LED bulb has a lifespan between 10k and 50k hours, making it a better option than either fluorescent lights, HIDs, or incandescent lights. A good fluorescent grow light can be expected to last 20,000 hours.
LED Vs. Fluorescent Grow Lights: Which Is Better
While LEDs or fluorescent grow lights can be a good choice depending on the situation, the full-spectrum LED is usually the better option for indoor growers. The LEDs make more sense than fluorescent grow lights or other options between the lower energy bills, the higher light output, little heat, and long-term affordability. That said, fluorescent fixtures can be a great choice if you’re looking for a more affordable upfront cost – or you’re looking for a light for seed starting.
Should You Use A Grow Tent?
Whether you’re using LEDs or fluorescent grow lights, a grow tent is always an excellent option for growing in a small space. Grow tents provide a suitable atmosphere for your indoor garden, allowing you to have fresh vegetables all year. Grow tents allow you to manage the amount of light, water, temperature, and humidity in your growing environment, allowing your plants to grow quicker and more robust – with better energy efficiency.
Grow Tent Options
When it comes down to it, the choice of LEDs vs. fluorescent lights comes down to preference and need. The bottom line is that LEDs are better options in the long term than other lighting systems, based on their efficiency and quality. That said, different types of plants, such as small plants, can do very well under a fluorescent light. But as LED technology continues to improve, the cost difference gap will continue to close, and the type of bulb you purchase will likely not be in the fluorescent, incandescent, or HID category for too much longer.
Do you have grow lights and opinions? We want to hear them! There is a lot of healthy debate in the grow light space. If you have thoughts on this topic or experience growing with fluorescent lamps, please let us know. We may even feature you in an upcoming article.