2 Grow Lights, 1 Winner : White vs. Purple LED Lights (Part 1)
No questions asked. Grow lights are a godsend to growers.
Depending on the type of grow lights you purchase, you can cultivate a wide array of indoor plants all year-round. But here comes the challenge. You have lots of grow light options on the market. Hence, making it harder to get a hold of the best one!
Look no further because I’ve got the ultimate guide about to grow lights! Like you, I am also curious to see the performances of different types of grow lights on my hydroponics set-up. Hence, I decided to make a series of grow light experiments! In this series, I’ll be testing two grow lights to see which is better in growing hydroponic plants.
And for the first part of this series, I test out two popular grow light options: White LED light and a Blue-Red/ Purple LED light. In case you’re wondering, I have tried both of them in my hydroponics system. So if you’re curious to know which works better for cultivating plants like red leaf lettuce, I suggest you read on. Or better yet, you can also check my video below to see how each product works in action!
Table of Contents
Types of Grow Lights
Let’s be honest. LED lights are the most popular options for growers nowadays. That’s why I chose to feature them in this experiment! But, aren’t you also curious about the other types?
One of the questions a lot of growers have about indoor grow setup is what are the different types of lights they can use. No worries because this section has the right answer for that! For starters, you can choose among 4 types of grow lights on the market. Let’s start with the most affordable one!
Incandescent Lights
I’m pretty sure you have a bulb or two of this type lying at home. As you know, incandescent lights generally come in frosted or clear bulbs. I can see why a lot of beginning growers turn to this type because it is so inexpensive! The main downside with this, though, is that it usually gives out high heat output which may burn plants.
Fluorescent Lights/ CFL
Fluorescent light is another popular option for beginning growers. Unlike incandescent lights, this has a lower heat output. Not to mention, it features just the right spectrum of light for growing. In case you’re wondering, this comes as a tube light or compact fluorescent (CFL) light. Another thing worth mentioning is that it’s a bit more expensive than an incandescent light.
LED Lights
If you’re looking for the most advanced grow light technology, then get yourself a LED light. Like fluorescent lights, LED lights are energy-efficient. Moreover, they give out an extremely low heat output, even lower than that of fluorescent lights. But here comes my favorite: they feature a fuller light spectrum range. They’re available in a wide array of colors to satisfy your plant’s growing needs.
Those are just some of the reasons why a lot of growers choose to use LED grow lights. Hence, for this experiment, I am going to test a white LED light and a purple LED light.
High-Intensity Discharge or HID bulbs
HID bulbs are pretty much the gold standard in indoor commercial growing. Although they are quite expensive, you’ll never go wrong with using this. They produce extremely high light output while giving off just the right heat for your plants.
And if you’ve come across grow lights with Metal Halide, Ceramic Metal Halide, or even High-Pressure Sodium bulbs, don’t be surprised because those are also considered High-Intensity Discharge Grow Lights.
The Hypothesis on the Grow Lights Test
Wait! Before we dive into the set-up and results, I think it’s only fitting that I share with you my hypothesis on which grow light fares better in the experiment. Would it be the white or the purple LED light?
Here’s my guess. If you consider the concept of lumens and spectrum difference, then the white LED Light would yield better results than the purple LED Light. I’ve talked about these concepts in the video below, so I suggest you check that out!
Here’s the thing. As you know, purple LED lights only consist of the blue and red color spectrum. But with white LED light, you’ll get red, green, and blue. That is more than what purple LED lights can offer!
But the main question here is, “Is my hypothesis correct?.” Let’s test it out!
The Setup for the Grow Lights Test
Who says we can’t use the Kratky Method for this test? Surely not me!
As you can see, my setup was pretty simple. I prepared two grow containers filled with nutrient/water mix. In case you’re wondering, the nutrient/water mixes that I used were made from the same batch to ensure the accuracy of the result. I also added air bubblers for aeration.
Grow Lights
On the left side, I popped in two white LED lights unto the lamp. While on the other side, I hanged the purple LED lights. As for the placement, I just placed them directly above the containers. I also made sure that they are at the same distance away from the plants.
But when it comes to the direction of the light, I figured that the purple LED one is at an advantage because its light faces downwards. Hence, I customized the white LED lamp with reflectors to ensure that the light doesn’t scatter in other directions but towards the plant.
Indoor Plant
As for the plant, I transplanted a two-week old red leaf lettuce into each grow container. Don’t be surprised if the mature plant on the white LED side is a bit smaller than that of the purple LED side! This would make things easier to test my hypothesis.
If you remember, I hypothesized that the white LED light works better than the purple LED light. Having that in mind, the smaller red leaf lettuce on the white LED side should be able to catch up or grow lusher than the one on the purple LED side.
KOR 9W LED A19 Light Bulb (60W Equivalent), UL Listed, 5000K (Bright White Daylight), 800 Lumens, Non-Dimmable
Hytekgro LED Grow Light 45W Plant Lights Red Blue White Panel Growing Lamps for Indoor Plants Seedling Vegetable and Flower (2 Pack)
The Grow Lights Test Result (SURPRISING!)
You’re not alone! The result of the test also came as a surprise for me.
This is the reason why tests or experiments are important. As you can see in the photo, the lettuce on the white LED light side did not grow as lush as the one on the purple LED side. Hence, this disproves my hypothesis that the white LED light bulb is more efficient than the purple LED light.
Aside from the lushness, let’s take a look at how each plant fares in taste and weight!
Weight
I’m pretty sure you have already guessed the winner in this criterion. Since the lettuce on the purple LED side is bigger and lusher, then that also means it’s heavier than the one on the white LED side.
Taste
Surprisingly, there’s not much of a difference between the two plants in terms of taste. Both have a soft and buttery texture. Not to mention, they’re yummy too! By the way, it’s not just me who said this, even my wife says so.
Pros and Cons:
White vs Purple LED Lights
To make things easier for you, I rounded up my positive and negative observations about these two products. So, check them out!
White LED Light
Pros
- Inexpensive
- Energy-efficient
- Ultra-low heat output/ cooler temperature
- Fuller light spectrum (red, green, and blue)
- Can be used as a grow light during the seeding cycle
Con
- Might not be an ideal grow light during vegetative and flowering cycles. As seen in the grow lights test result, the plant under white LED light did not grow bigger and heavier than the other plant.
Purple LED Light
Pros
- Energy-efficient
- Ultra-low heat output/ cooler temperature
- Easy to set-up
- Ideal for growing light during the vegetative and flowering cycles. As you’ve seen in the result, the plant on the purple LED side grew heavier and lusher than the other.
Cons
- Might be too harsh for the eyes
- On the pricier side
- Does not feature a full light spectrum
Frequently Asked Questions on Grow Lights
Here’s the thing. It’s not enough that you know which type of grow lights work well in your gardening system. It’s also important to know where to place them as well as how long you should leave them on. No worries, I answered those questions in this section! So, check this out!
Q1. Should I get grow bulbs or grow light fixtures?
Again, it all boils down to your preferences and growing needs.
If you’re looking for a cheaper option, then you can go for grow light bulbs like the LED one I used here. Not to mention, they’re convenient and can be easily set-up. Just like what I did, you can just take an old lamp and pop in a bulb or two of the grow lights.
If you’re willing to shelve out a few more bucks for a holistic solution to your grow light needs, then go ahead and order a grow light fixture. It’s great because a single light fixture can illuminate multiple plants. You’ll see that the light and heat are equally dispersed throughout your plants. A great example of a light fixture is the LED light I used in the experiment.
Q2. Where to place the grow lights?
I’m pretty sure you know my answer to this question. But for those who are still starting out, grow lights should be placed overhead or directly above your plants. This enables grow lights to provide efficient illumination to your plants.
But another thing you should take note of is the distance. In case you’re wondering, incandescent lights are pretty hot. Thus, I suggest you place it at least 24 inches above your plants. While for fluorescent lights, you can inch them closer to your plants by at most 12 inches. As for LED lights, you can go ham by keeping them close to about 6 inches.
Q3. How long should I keep grow lights on? Should I turn them off?
The answer to this depends on a lot of factors such as the type of plant and the grow light you have. I find that keeping them on for 12-16 hours works best.
As for the second question, grow lights and plants also need rest. Tons of it, actually. When it comes to growth, darkness is as important as sunlight. If sunlight allows plants to produce energy during the day, the darkness allows to break the energy down for your plant’s growth. Hence, it’s important to let your grow lights take a rest once a day. And besides, this is a great strategy to save up on electricity bills!
Q4. Are blue LED lights bad for humans?
I won’t necessarily agree that blue LED grow lights are harmful to humans. But there are some potential dangers that you might get from it, especially if you don’t take precautions.
As experienced by many with mobile phones and gadgets, exposure to blue light negatively affects our sleep pattern. We’ve all heard about this. It has been a very hot topic amongst parents and kids!
Another potential danger is retinal damage. Studies have shown that frequent exposure to blue light may affect our eyes which may result in vision loss.
Again, I’ve been using my purple LED lights for a while now and I find that they’re pretty safe to use. I have not had problems with my sleep pattern and vision. I believe this is the case for me because I make sure that I don’t get too exposed to the LED lights.
Hence, as long as you stay away from too much exposure to blue light, then I’d say your safe from those potential dangers. Or better yet, you can wear nice sunglasses as another protection.
Conclusion
We all know it. Grow lights are essential to keeping your plants healthy and happy. As you know by now, LED lights are the most popular choice for growers. That’s why I made an experiment where I tested two types of LED lights: White vs. Purple.
Based on the experiment, the Purple LED performs more efficiently than the White LED in growing plants like hydroponic lettuce.
But wait… there’s more! As mentioned, I’m going to make this a series. You’ll be able to get an exclusive glimpse of how different types of grow lights perform in my hydroponics system. To give you a hint, I’ll also be testing out the Sansi LED light!
Oh and before I forget, do check out my ultimate guide to grow room air conditioners. As you know, grow lights might make your grow room a little too hot. Thus, I suggest you check my article out and invest in an efficient air conditioner to avoid that!
So, what other types of grow lights would you like me to test out? I’d love to hear your suggestions in the comments section!
You can check out other blogs at Rudd’s Home Farming to learn more tips and tricks in hydroponics gardening.
