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Writer's pictureBimal Parmar

Choosing Your Grow Lights



Why do I need Grow Lights?


Since you’re going to be growing inside, the light may not be sufficient for the needs of some plants. Actually, there are very few vegetables that will grow well indoors without a grow light.


Grow lights are artificial light sources, used to grow plants. These lights work by producing a light spectrum suitable for photosynthesis. Indoor grow lights are used in situations where there is either not enough natural light to grow a plant or where additional light is needed.


Grow lights are a great way to increase the amount of time that plants receive light, to help them grow faster, or to grow in situations where there would otherwise be insufficient light.


Depending on the type of plant to be grown, natural conditions are imitated using different shades, colors, temperatures and intensity of light. You can use indoor grow lights in your house to grow garden plants all year round. Grow lights can even be used for the production of food on a commercial scale.


What do I need to know before choosing?


Before you choose the grow lights for your indoor vegetable garden, it’s important to understand the different options, how they work and the situation they’re best suited for.


Light Spectrum



The wavelength of light is measured in nanometers (nm), and it determines the color of the light emitted from a source. It also affects whether it is visible at all, or falls in the infrared or ultraviolet parts of the spectrum. Plants are better at absorbing and using light in the red and blue parts of the spectrum, and reflect more light in the green part of the spectrum. This is why the leaves of many plants appear green.


Blue light is used mostly for vegetative stages to establish leaves and roots.Meanwhile, red light is used for producing flowers and fruit.Grow lights come in two types: Targeted spectrum and full spectrum.


Targeted spectrum lights emit a specific color, like red or blue. As a result, they’re best for only specific crops or specific growth stages. Full spectrum lights imitate sunlight more naturally and cover all stages of growth. Plus, because full spectrum bulbs emit white light, it’s easier for us humans to see.



Light Intensity



Intensity refers to how much light actually reaches the plants from the fixture. Intensity is important because you’ll want to be sure you can provide the right amount of light for the number of plants you have at each stage of their growth cycles.The higher the intensity of a grow light, the farther you can place it from the plants to minimize heat and light burns.


To decide if the intensity is right for your desired coverage area, consult the manufacturer. The manufacturer will provide an estimated coverage area. However, if you want the best results possible, you’ll need to go a bit further.


First, find the photosynthetic photon flux density (PPFD) measurement of the light. This measurement is the average density of the total light output of the fixture. It indicates how intense the light is within a set area. Keep in mind that light intensity is higher at a center point and gradually lessens as you move away from that spot. That’s why you’ll next want to consult the manufacturer’s photosynthetic active radiation (PAR) chart.


The PAR chart shows the distribution of the light’s PPFD in an area.The density will be most intense in the middle, less intense on the edges, and least intense in the corners. Ideally, you want a light that has a low PPFD with an even distribution, as shown in the PAR chart. This will influence the number of grow lights you’ll want for your grow space.


What color should I get?



For growing seedlings indoors, choose a grow light that is described as “full-spectrum” or broad spectrum. With a full-spectrum light, you’re getting a good balance of both blue and red light – and the closest thing possible to natural sunlight.


Cool blue light is great for promoting leafy green foliage but also regulates plant growth, keeping plants short and stocky. This is great for microgreens and seedlings (or plants in the ‘veg’ stage), but too much blue can also lead to stunted plants over time.


Warm red light stimulates both vegetative growth and flowering, yet excess red light can make plants tall and lanky. Average household incandescent light bulbs emit mostly warm light, giving off a comfortable and cozy vibe – but not ideal for plants.


If the grow light temperature isn’t stated outright, look for its Kelvin rating. That will tell you the color of light it will emit. A full-spectrum grow light that closely resembles daylight will have a Kelvin rating of 5000 to 6500K. Cooler blue grow lights are rated around 4000 Kelvins, while warm or reddish lamps have even lower ratings – around 3000K. If you can’t find a full-spectrum light in the ideal Kelvin range that also fits your other needs (budget, size, availability, etc) a “cool white” light (4100-4500K) will also work well for germinating vegetable seedlings, growing microgreens, and raising young transplants.


Fluorescent vs LED Grow Lights


LED grow lights are extremely popular these days! LED, which stands for light emitting diodes, are very efficient, and can also be quite powerful. Yet some old school gardeners swear by their classic fluorescent lights instead.


Note that there are many types of ‘fluorescent’ lights, including compact fluorescent lights (CFLs), basic fluorescent tubes, high-output T5 fluorescent tubes, and more. When it comes to fluorescent grow lights, T5s are considered the best choice for plants. T8 tubes aren’t quite as effective and bright, but are cheaper and can do a decent job for indoors seedlings or lettuce plants.


In general, a standard 45 or 60 watt incandescent light bulb (or LED equivalent) that you’d use in a household lamp fixture will not provide sufficient light for starting seeds or growing other plants that require ample light.


Differences between LED and fluorescents:


LED lights are generally more energy-efficient than fluorescents, and therefore lead to lower electric bills.


  • LED lights typically have a higher upfront cost than classic fluorescent tube lights, but may have a longer lifespan.

  • Since they’re made up of dozens of diodes, LED lights come in a wider variety of shapes and sizes. T5 fluorescents are long slender tubes (e.g. “shop lights”) with either one or several tubes mounted in a ballast fixture.

  • Per watt, LED lights give off more lumens of light. Therefore, a compact LED fixture has the potential to give off stronger light than a comparatively larger T5 fixture (but it depends on each light’s specifications). Some LED lights are weaker than T5s.


Personally, I prefer LED lights as they do not give off any heat and are cool to the touch. I have a couple of 4 foot Full Spectrum lights that are rated at only 60w


My Recommendations




This set of lights was a great buy. The lights draw very little electricity with each light only using as much as a 60w incandescent bulb. I’ve had them now for 4 months and they work very well. They were extremely easy to set up and I’ve strung two together off a single switch which comes with it. I use these vertically in front of my VegWall Garden using some brackets I made with curtain rods.

My only con is that I would not get the red light next time. It’s not good for your eyes and when your lights are in a living space they cast an annoying purple glow. I ended up building a grow tent around everything.





Initially I was disappointed when I opened the box and saw four tiny tubes. I thought I was getting four foot lights! Anyway, they were super easy to connect and get going. They’ve been working great as I put them on a shelf above the trays. Plants are growing great! Again, I would not get the red lights next time as mentioned above.





I bought these because I needed more lighting for the shelf. Just like #2 but they’re all white light. So much less annoying.


Hope this post helps in choosing the right grow lights for your indoor vegetable garden.

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