Full Guide – How to Choose the Right LED Grow Light for Indoor Plants

With so many types of grow lights and systems available, it can be overwhelming to figure out which one will best suit your needs. In this article, we will give you a comprehensive explanation of how to choose the right supplemental lighting for your indoor garden.

Main Topics in this article

1. Definition of grow light
2. Uses of grow light
3. Types of grow light
4. Key factors of choosing a grow light
5. Advantages of SANSI grow light
6. FAQs of grow light

1. What are Grow Lights

Generally an electric light, designed to stimulate plant growth by emitting an electromagnetic spectrum appropriate for photosynthesis.

2. Grow Light Uses

Keeping plants alive and helping them flourish can be hard as is, but growing things indoors is even trickier, especially during winter when light levels are reduced even further.

When there is insufficient light, the grow light can supplement light to plants and promote the progress of plant photosynthesis. The grow light is very important for the seeding, growing, flowering and fruiting of plants.

There are 4 main uses for grow light: seedlings, propagation, growing food, and limited light.

Seedlings: Grow lights can be used to assist with the propagation of indoor plants from seedlings since seedlings need enough light and warm temperature to grow healthy.

Propagation: If you love propagating plants to give as gifts or as a side hustle, you must have grow lights to properly propagate your indoor plants.

Growing Food: Of course, if you have an indoor garden of greens and herbs, you definitely need grow lights for them to grow correctly.

Limited Light: Grow light can help indoor plants to grow healthy and strong, especially during the colder months. Grow lights can also be used as artificial lighting for rooms with limited light or no sunlight.

By providing the specific color spectrum needs for the plants, grow lights can not only promote the plants’ growth, prolong the flowering period, intensify flower color, but also can increase crop production efficiency, yield in advance, and enhance quality and taste.

3. Types of Grow Lights

- Incandescent bulbs cost just a few dollars and are the cheapest option. Although they may do just fine for a few plants or used in conjunction with natural light in a sunny room, the heat of these bulbs requires a distance of two feet or more to prevent heat damage and should be used cautiously.

- Fluorescent lights are the most popular choice for home growers. Some newer types offer a wider light spectrum for all-purpose use, but traditional fluorescent bulbs lack the appropriate range for flowering and are best suited for germination and vegetative growth. Because they produce less heat, fluorescent lights are safer, more versatile and more effective than incandescent bulbs while remaining budget-friendly. 

- HID lights - High Intensity Discharge solutions like Metal Halide (MH) and High-Pressure Sodium (HPS) lights are good choices, though expensive to purchase and operate. Extremely efficient, high-energy discharge throw a lot of light and the blue light of MH lights will promote vegetative growth, but produce less flowering. The red to orange hue of HPS lights are powerhouses when it comes to producing buds and flowers, but plants will be less sturdy. Used in tandem, MH lights are often used to promote leafy growth before swapping in HPS lights to encourage plants to flower. 

- LED (light emitting diode) lights are the new kid on the block and are finding some popularity. They use half the electricity fluorescents require and last five times longer than the average fluorescent bulb. Emitting virtually no heat and requiring little power to operate, LEDs can be programmed to accurately simulate the 5700K color temperature of sunlight and can simultaneously produce the red and blue band spectrums needed for both vegetative growth and flowering Though LED lamps cost slightly more than traditional grow lights, their durability and efficiency make them cheaper in the long run. They also give off less heat and mercury-free LED tubes don't shatter like glass fluorescent tubes, leading to fewer safety hazards.

4 types of grow lights

4. Main factors of choosing the best grow light

Now you may have a basic knowledge of the grow light, then we will go ahead to our main topic – How to choose the right LED grow light for indoor growing?

There are many different types of LED grow lights and LED grow light bulbs on the market. Different factors will affect which grow light bulb is best for you. These factors you should consider:

• Light Spectrums – the optimal red and blue wavelengths to grow big, healthy, and strong.
• Light intensity – PPFD / PPF - High Light Output (PPF) – Higher PPFD/PPF = more nourishment
• Grow Light Efficiency - PPF/W – Higher PPF/W = more energy-efficient
• Light Technology – low heat, long-lasting, safe
• And more… - CRI, design, material, durable, warranty, certification…

4.1. Light Spectrum

A color spectrum is a graphical display of each of the colors in the light. Scientists use wavelength numbers to refer to the colors instead of color names, which is a much more accurate way to measure the color.

The various light colors effect plants growth differently. This is not all visible to the naked eye. Typically, what humans refer to as "light" is actually only the visible area of the light spectrum (~400 - 750 nanometers).

This visible light spectrum range covers most of the range of wavelengths needed to grow plants, known as the PAR or photosynthetically active radiation.

Different wavelengths of light have different effects on plant photosynthesis. The light required for plant photosynthesis has a wavelength of about 400-700nm. 400-500nm (blue) light and 610-720nm (red) contribute the most to photosynthesis.

Blue (470nm) and red (630nm) LEDs can just provide the light needed by plants. Therefore, the ideal choice for LED plant lights is to use a combination of these two colors. In terms of visual effects, the red and blue plant lights are pink.

Blue light can promote the growth of green leaves
Red light is helpful for flowering and fruiting and prolonging the flowering period.

Sansi 24W Adjustable 3-Head Clip-on Grow Light could be a great choice for you if you’re looking for a specific color of grow light, comes with 3 spectrum modes (blue light, red light, blue + red light (pink))

There's a variety of plants and each of them has different habits, and also different growth stages have different light needs. For the healthiest plants you really need to include light from right across the color spectrum. While it’s true that certain types of light may be more effective at different stages of the growth cycle, your plants still need light from across the spectrum at any stage of their growth. If you concentrate your light too much on one end of the spectrum you probably won’t like the results. The spectrum required for plant growth should be a continuous spectrum with a certain distribution width. It is obviously inappropriate to use a light source made of two specific wavelength chips of red and blue with a very narrow spectrum.

Full spectrum means all colors (but means much more than just color named Electromagnetic spectrum) produced from natural light and a term used for grow lights.

Full-spectrum grow lights are the closest to real sunlight and will help your plants grow the best. Natural sunlight emits all spectrums of light, even ultraviolet and infrared, which aren’t visible to the naked eye. 

Conclusion: Blue is used to encourage bushy growth in plants, the vegetation and the germination of seeds 'stage of growth'. Red colored light is for encouraging budding, flowering and fruiting. Too much red light can cause serious problems, namely lanky and spindly plants. Too much blue light, however, will result in stunted plants.

Grow lights should provide the proper spectrum of light for photosynthesis, which key to plant growth. Lights that provide a full spectrum are the ideal choice for your growing space. Here we'd like to recommend you the 24W grow light with 3 spectrum modes and the right SANSI full-spectrum grow lights, so that you can manipulate the type of light your plants are exposed to in order to optimize their growth at different growth stages.

4.2. Light intensity - PPFD (photosynthesis flux density, PPFD)

Both PPFD and Lux are units used to measure the intensity of light. Lux is universally used to measure and compare the brightness of visible light that reaches a surface, also referred to as illuminance. PPFD is referring to the amount of light suitable for active photosynthesis of plants.

Whenever dealing with lighting conditions of plants, Lux might not accurately represent the real light intensity suitable for photosynthesis. If you’re seeking the optimum PAR range, switch to PPFD. If you want to determine the overall light intensity in your grow room, choose the unit of your liking – PPFD or the lux option, here we will explain the PPFD in details.

For grow light, wattage is not as important as you think, but the light intensity (PPFD) is the very most important factor when choosing grow light.

The amount of light is actually measured as PPFD (Photosynthetic Photon Flux Density), sometimes abbreviated to PPF (Photosynthetic Photon Flux, umol/s). PPFD is a better way to measure the quantity of light for LED grow lights, than lumens. 

PPFD is a ‘spot’ measurement that tells you how many photons from the PAR range hit a specific area of your canopy over time. It is expressed as micro moles per square meter per second (μmol/m2/s).

Note that the PPFD value is heavily dependent on two factors that can vary widely: the distance between the LEDs and the plant, and the loss of PPF from vegetation canopy. 

The more light reaches the plants (μmol/m2/s, aka PPFD), the greater the rate of photosynthesis. But light can only do so much: after approximately 350 μmol/m2/s, light stops having as much of an effect on photosynthesis, since the plant’s chloroplasts can only process so much light at a time.

Generally, positive plant PPFD> 50 μmol·m-2·s-1 can start the photosynthesis mechanism; while shade plant PPFD only needs 20 μmol·m-2·s-1. Therefore, when installing LED plant lights, you can install and set according to this reference value, select the appropriate installation height, and achieve the ideal PPFD value and uniformity on the leaf surface.

A Summary PAR Readings (so you have context and understanding of light intensity) ^source

• 50–70 umol/m2/s PPFD – Greenhouse, Low Light (Under Bench)
• 100 umol/m2/s (morning/evening) up to 250 mid-day maximum – Greenhouse, Moderate Light (Bench Level)
• 200–500 umol/m2/s average with a peak intensities reaching 800-900 – Greenhouse, High Light (Roof Level)
• 2,000–2,200 umol/m2/s – Outside Direct Sun (Unshaded/Full)

Light Suggestions for Orchids (PPFD or PAR Recommendations)

• Low-Light Orchids (Mottled-Leaf Paphs, Jewel Orchids, Phals): 40–80 umol/m2/s PPFD (20 umol/ft2/s)
• Moderate-Light Orchids (Onc, Phrags, Epidens, Dends etc): 80–150 umol/m2/s PPFD (30-40 umol/ft2/s)
• High-Light Orchids (Cattleya): 150–350 umol/m2/s PPFD (50-100 umol/ft2/s)
• Very High-Light Orchids (Vandas): 350–600 umol/m2/s PPFD (50-100 umol/ft2/s)

Light Suggestions for Aroids & Tropical Houseplants (PPFD or PAR Recommendations)

• Very Low-Light Houseplants (Begonia pavonina): 20–40 umol/m2/s PPFD (20 umol/ft2/s)
• Low-Light Plants (African Violets, Tropical Begonias): 40–80 umol/m2/s PPFD (20 umol/ft2/s)
• Moderate-Light Houseplants (Low-light Aroids like Anthuriums and Pothos): 80–150 umol/m2/s PPFD (30-40 umol/ft2/s)
• High-Light Houseplants (Tropical Succulents like Christmas Cactus, Philodendrons, Monstera): 150–350 umol/m2/s PPFD (50-100 umol/ft2/s)
• Very High-Light Houseplants (Tropical Trees like Chocolate, Citrus, etc): 350–600 umol/m2/s PPFD (50-100 umol/ft2/s)
• Full-Sun Plants (Cannabis, Fruiting Trees/Shrubs, Eucalyptus, Desert Cacti): 600–2,200 umol/m2/s PPFD 

*Converting meters to feet: 1m = 3.28ft

**NOTE: These are general suggestions not EXACT numbers; you can expect that +/- 50-100 umol/m2/s is likely okay and individual orchid species may be adapted to a range beyond these numbers—for example, a lot of strap-leafed paphs can take closer to 150 umol/m2/s. I encourage you to use this information to help you benchmark where your light should be, but as with all things related to horticulture and plant care, adjust based on your conditions and how your plants perform, look and grow.

SANSI Full-spectrum Grow Lights PPFD Comparision

* SANSI 70W LED grow light has a higher PPFD, you can learn about the light here >>

4.3 Grow Light Efficiency - PPF/W

In order to know how effective a grow light is at growing plants, we need to understand what is called its ‘efficacy’. That is, how efficient is it at converting the Watts we’re putting in, with plant-available light that comes out.

Watts go IN to a grow light. PPF is what comes OUT. To understand the efficacy of a grow light, we simply divide one by the other – i.e. PPF per Watt (PPF/W) or PPFD per Watt (PPFD/W).

A higher value of PPF/W means a higher light efficiency, here’s the SANSI Full-spectrum LED grow light PPF/W chart

* SANSI 36W LED grow light bulb has a higher light efficiency, you can learn about the light here >> 

Higher light efficiency means more energy-saving. The energy that we use for growing light indoors starts off as a watt.

To put this into the context of a grow light for plants, it’s useful to consider a simple example.

• Let’s say we have a grow light that consumes SANSI 24W. That is equivalent to 0.024KW.
• If we left that grow light on for say 14hours a day, then we’d be consuming 14 x 0.024 = 0.336KWH per day.
• Do that for an entire year, and we’d use 0.336 x 365=122.64KWH.
• The average price of electricity in the US in Nov 2021 was $0.1420, which means that the average cost of running a SANSI 24W grow light at 14hrs/day for an entire year in the US would be 122.64 x 0.1420 = $17.41.
• What’s more, you’re saving 12.5 times energy than a normal grow light, cause SANSI 24W is Equivaled 300W. 

* The average price of electricity is calculated as $0.1286 in the form above, you can have a calculation according to the local electricity price.

Besides the factors above, for choosing the very best grow lights you should know more about what any other technologies the light comes with. Here we’d like to introduce the technology what SANSI applied for the grow lights in details, and these features below will be a great comparation points for you.

5. SANSI Light Technology ensures the grow lights low-heat, long-lasting and safe!

All of SANSI grow lights are perfect for all stages of plant growth and utilizes patented Chip on Ceramic (COC) technology to improve luminous efficacy and lifespan (25,000 hours). The secondary optical design ensures that your plants get the most out of the light, and the unique hollow structure design make the lights low heat and safer for a continuous prolonged usage, all of these technologies make SANSI grow light an essential tool for any indoor garden. Plus, the full-spectrum light is ideal for any type of plant!

World-leading Patented Technology - Chip on Ceramic

Chip on Ceramic (COC technology), SANSI's Ceramic technology replaces the traditional Mcpcb aluminum substrate with a non-conductive ceramic heat sink, and directly solder the LED chip on the ceramic heat sink, effectively reducing the system thermal resistance between the LED PN junction and the surface of the heat sink, resulting in faster heat conduction and higher product reliability, making the SANSI bulbs have a higher light efficiency.

Benefits from SANSI patented COC technology: Higher PPFD output, lower energy costs, better heat dissipation, super-long lifespan (25,000 hours), excellent corrosion resistance (ceramic material).

The Secondary optical design

According to the supplementary lighting requirements through different growth phases, self-built mathematical calculation models and systems, through the lens for secondary scientific light distribution, improved light utilization, give plants more supplementary light, and improved light quality.

Safer - Independent design of IC (driver chip)

Use self-developed driver IC with has the ability to adjust its power outage to reduce its temperature, reaching the self-adaptive ambient temperature, meaning it can be used in completely enclosed lamps, greatly improving safety.

Durable and reliable – Unique material

The lamp body is made of special ceramic material, and the flame retardant grade reaches V0. Its reinforced insulation structure design ensures there’s no risk of electric shock and super-safe for home plant light supplementing. The whole shell material of the light reaches the WF2 anti-corrosion grade, which is more reliable and durable; low IR, less heat radiation, avoiding close Distance exposure burns plants.

Hollow structure design

The working heat of the lighting device is quickly transferred to the air through natural convection, and the heat dissipation is faster and the service life is prolonged.

Super-long lifespan - 25,000 hours
All of these advanced technology and special design that make the SANSI light a long-time lifespan to 25000 hours

Guarantees: 5 years warranty, ETL listed & CE certification, quality and safety verified

High CRI - Ra＞90, a natural light: Choose lighting that has a higher CRI rating so you can be sure you're getting the most accurate color portrayal in your home. Numerically, the highest possible CIE Ra value is 100 and would only be given to a source whose spectrum is identical to the spectrum of daylight. 

All the SANSI full-spectrum grow lights come with a natural light, giving you complete freedom to put your garden anywhere in your house, explore now!

Now you may have a full understanding of technical information about light spectrum, and PAR (photosynthetically active radiation), PPF/PPFD, CRI. PPFD measurement is wise when becoming more serious about growing. This will enable you to choose the right grow lights which are also efficient in costs when comparing all aspects, i.e., wattage, light output, set up and replacements.

Here's the full comparision table of SANSI grow lights, choose the right grow light for you plants now!

6. Frequently Asked Questions

Q1: How far away should LED grow lights be from plants

In general, LED grow lights should be 12-30 inches from the tops of plants. As plants grow, you'll adjust your lights to maintain a consistent distance from the plants. However, the distance will vary depending on the wattage of your lights, the type of plant, and the amount of ambient light.

For SANSI LED grow lights, we recommend that the best distance between the light and plants is 12 inches (30cm) to 20 inches (50cm).

Q2: How long should a grow light be left on?

The answer depends on a few factors, such as the type of grow light you’re using, the growing environment of your plant, and the type of plant you have, and the biggest factor is the growth stage of plants. However, in general, grow lights need to be on for at least 8-10 hours a day.
- During the seedling/growth stage, it is recommended that the plants need 16 hours light and 8 hours without the light.
- During the vegetative stage, it is recommended that the plants need 18 hours light and 6 hours without the light.
- During the flowering stage, it is recommended that the plants need 12 hours light and 12 hours without the light.

Check your seed packaging or plant tags, or ask at the nursery for specific suggestions. And make sure you turn your grow lights off every once in a while. No one likes to work 24 hours a day – even plants!

Q3: Sansi 70w grow floodlight has higher ppfd output but lower lux. Can you help clarify which measure is correct? 

If you have questions about how to choosing SANSI grow light or everything about grow light, just leave us comments below, we’d like to help.

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Source
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