How to Make Your Own DIY LED Grow Lights

With legalization sweeping the nation, manufacturers are quickly developing high-quality LED grow lights to suit virtually every purpose. Purchasing a grow light is certainly easy, but it’s not the best option for everyone. Many growers, both aspiring and experienced, are choosing to build their own lights. What many people don’t realize is that building your own DIY LED grow light is actually quite simple. With a little planning and elbow grease, you can drastically cut your startup costs by a sizable margin. Plus, designing your own lights allows you to create something adaptable that is built to suit your specific needs.

If building your own DIY LED grow light can save you money and build a more effective grow room, then why aren’t more people doing it? The unfortunate reality is that grow lights are very complicated little devices. Fortunately, we’ve created this guide to teach you everything you need to know to go DIY. Before you pick up that soldering iron, let’s take a look at some sample projects. We’ll show you the entire process from start to finish, so you’ll understand just how simple this project can be. After, we’ll explore the core concepts of how a DIY LED grow light works, arming you with the knowledge necessary to customize each design to suit your needs.

Project 1: Quick n’ Simple strip style DIY LED Grow Light

If you’re looking for the easiest way to get started, look no further than LED strip lights. You’re not going to have to mess around soldering wires together or manually placing individual LEDs. Instead, you’re essentially putting your own system together using partially manufactured strip lights.

The most important thing with this design is to make sure that you’re using the right kind of LED lights. There are plenty of guides online that instruct you to use architectural LED strips or inexpensive grow lights from China. These are appealing as they only cost a few dollars each, but are absolutely not suitable.

bad-led-strip-light

 

This is an example of what not to do. This user was excited, having found a seemingly suitable strip light for only $5 on eBay. But each of these lights are only rated at 1W each. Even when placed above the plant, this is considered under-powered. The lights aren’t designed with spectrum in mind, so the PAR value is quite low, and the lenses are poorly designed for the spread needed in a horticultural environment. This means that the light won’t hit your plant very well. Whatever small amount of light does hit your pant is going to produce very little photosynthesis.

LED Grow Light Strip

Instead, we’re going to build something like in the photo above. What makes this system good is that they’re using the correct lights, placed in the correct manner. The above image shows how a setup would look if you’re starting from seed, helping clones get established, or any other part of the early veg cycle. The layout is a little different for flowering, but we’ll show you how to build something that is adaptable.

Who This Project is For

This strip style DIY LED grow light is for anyone who wants control over how their grow room is set up. This isn’t your typical DIY where you’re going to assemble every single part of the equation. Instead, it’s like buying a number of tiny pre-configured grow lights and building the exact system you need. This means that it’s suitable for beginners, but does come with a bit of additional cost. The trade off is that, even if a large grow room costs you as much as it would to buy pre-made lights, the room will often be much more space effecient. You’ve got the ability to pack your plants more densely, reinforce areas with little light, and obtain significantly high yield per foot than you would with other grow lights. Whether you’re looking to make a room as compact as possible, or increase yield by having seperate vegitation and flowering areas, this design has something for everyone.

How it Works
The foundation of this system is the the GalaxyHydro 108W waterproof LED Grow Light. This long strip has 36 LEDs in total, each of them running at close to their maximum rating of 3W. There are hundreds of other strip lights on the market, but none come close to the output and spectrum of this one. Plus, instead of being mounted in a long strand like some models, it’s in it’s own aluminum frame. This means that you won’t have to build complicated cooling systems, and you’ll have a much easier time mounting the lights themselves. We’re going to show you a sample build that will create a growing space five feet wide and four feet high. This will allow you to grow six plants each in their own separate 5 gallon bucket, and take then through both the flowering and vegetation stages. This is currently the maximum number of plants you’re allowed to grow in California. Could you squeeze a few more plants out of this system? Absolutely. But it’s important to remember that plants need more light during their flowering cycle, so we’re being conservative with this system to maximize yield.

What You Need:
This system is incredibly simple both to buy and assemble. You only need a few key parts to get started

  1. 10 x GalaxyHydro 108W waterproof LED Grow Lights
  2. 2 x Coleman Cable 04657 6 Outlet Metal Power Strip
  3. 1 x HydroFarm Dual Outlet Light Timer
  4. Mounting Bracket (pick one)
    1. 2x Ausable 3/32 Coyote & Fox Snare (pack of 12) OR
    2. Strips of 2×2 wood from the hardware store
  5.  1x 50 pcs Screw Hook

How to Assemble
This system is very easy to assemble. Each strip in this DIY LED grow light works independently. They should be spaced 6″ from each other. A single light is is 4 feet in length, and with 6″ in between each one you’ll get 5 feet of width with the 10 lights. They should be hung 12″ to 18″ from the top of your plant. Since your plants grow, in an ideal world you’ll be able to raise and lower the lights as you plants grow, and that’s where the fox snare comes in. It’s made from aircraft cable, composed of very thin strands of stainless steel bands that can withstand a lot of use. It only takes a matter of minutes to raise of lower them thanks to the clamp on grip. You can anchor them above the lights, or on the wall and use the screw hooks with the cable at a 45 degree angle.

Mounting DIY LED grow lights

hanging a strip style DIY LED grow light

You’ll want to hook up all 10 lights 6″ apart in a row like this. Once that’s completed, you can begin routing the cables. Each of these lights has a long 6 foot cord that goes to the individual lights, each with it’s own LED driver. Usually, we wouldn’t recommend connecting multiple lights to the same circuit. But since these lights are only 100W each, we can connect them in groups of 5.

First, you’ll want to plug in your light timer. There are two outlets on each side. You’ll want to plug in your outdoor power strip into each one. This strip is a little more expensive than some, but it’s designed for use in a humid environment. You can then plug in 5 lights into each strip. From this point, your setup is pretty much good to go!

Customization
the best thing about a DIY LED grow light is that you don’t have to follow our directions exactly. You can add more lights, or remove them from the system as needed. You can mount them to a rigid wood structure if you want to have two rows of plants, one above the other.

But the two main changes you can make are the spacing and type of lights you use. The system we’ve designed above is suited for both veg and bloom cycles. If you are only going to be using them for the veg cycle, you can space the lights out by a foot. This will give you space for more plants, but as they become dense you’ll find that the light is no longer adequate and you’ll need to move them to a bloom specific setup.

If you’re using the lights only for bloom, you can sub out half of the lights. The GalaxyHydro 108W LED strip lights are also available in a bloom only light that produces a slightly different spectrum of lights than the others. It’s important to remember that these are just reinforcement lights. You still need to use the standard ones as well. You’d want to alternate them, so the first light is standard, and the following one is the bloom light.

Project 2: Fully Custom COB LED Grow Light

DIY LED Grow Light

If you’re willing to get a little more hands on, you can build a fantastic LED grow light from cree COBs. COB stands for chip on board. It’s a type of light that doesn’t require you to manually solder each of the individual LEDs, as part of the circuit is included. This is the easiest way to build a fully custom light, and can produce some incredible results. There are tons of COB lights available, but the Cree models are our most highly recommended. Their 1.9A design is a great compromise between power and efficiency, and you’ll only need four of them for a small grow. If you want to grow more plants, you can easily double up the design to have 8, 12, or even 16 lights. The total cost per set of 4 lights is going to be around $XXX.

Who is This Project For?
This project is perfect for anyone on a tight budget, who has a small amount of technical skill. Even if you’re new to this kind of work, you’ll only have a small learning curve to get started. If you’re looking to expand in the future, it will be easy to add more lights at a later time.

What You Need
To get these lights working, you’ll need a few different components. Of course, you’ll need the LEDs itself. Then, you’ll need a driver. The LED driver is the electrical circuit that converts power to the exact type used by the lights. Your driver determines the efficiency of your lights, as well as the longevity. If you use a high power driver and push the lights to their capacity, you’ll get the most output. But you’ll also run the risk of burning the lights out. It’s worth noting that most drivers aren’t perfect. Power output can vary up to 10% from the rated specification. This is why we never recommend buying the largest driver the lights can handle. If they heat up and start cranking out a little too much power, you can damage your LEDs. We find that the best balance of price, performance, and reliability comes from using 1.4A drivers with the 1.9A COBs. Next, you’ll need a cooling system to keep the lights from burning out. This is very important since the lights will be on for 12 or more hours at at time. Finally, we’ll pair our heatsink with a fan to improve the cooling.

We recommend the following parts for a single strip of 4 lights:

  1. 4 x Cree High Power LEDs 3000K
  2. 4x 50W LED driver
  3. 4 x Startech Socket 7 CPU Cooler
  4. 1 x StarTech Metal Oxide Thermal Paste
  5. 1 x roll of 18 gauge alarm wire (or any copper core wire from your local hardware store)
  6. 1 x 12V power Supply
  7. 4 x COB holders
  8. Screws

How to Assemble
Although it can seem a little complicated at first, getting this DIY LED grow light together is pretty straight forward. The first step is to mount your LED lights to the heatsink. You’ll have to drill and tap the heatsink to mount the COBs. Use a standard drill bit, aluminum is quite soft so you won’t have any trouble with a standard drill or even a dremel. Remember to use a drill bit that is 1/8th of an inch smaller than the thread on your screw. Then, you can take a standard tap and die set and slowly set the threads. If you haven’t done this before, this video will show you how.

When you mount the COBs, you’ll start by putting a tiny dab of thermal paste on the back of the LED itself. you can then put it into the holder, and screw it in place. You don’t have to make it too tight, just turn until you start to feel some pressure. The thermal paste will expand and allow for effective heat transfer.

Once these are in place, you’ll want to start getting your wiring together. We recommend mounting all of the LED drivers to a board to hold them in place. You’ll then want to connect them in parallel to your 120V power source. This means that all of the positive connections go to the single positive terminal, and all of the neutral cables to the neutral cable. You don’t want to be daisy chaining them together. You’ll probably come across some guides that show you to connect the negetive terminal of one driver to the positive of the next, and so on until they’re all in line. That won’t work with these drivers. Doing so would double the voltage drop against each device, so the final lights will wind up either under powered or ineffective. In parallel, the voltage remains the same while the current increases, allowing us to connect as many lights as we want.

You can also connect the 12V power supply to a seperate 120V terminal. Technically, you could probably put it in parallel with the drivers, but we recommend avoiding it. This power supply is very low current, so it’s not ideal to have it connected with high current devices. If one light was to die, the resulting surge would destroy the power supply and likely your fans as well.

From here, each COB can be connected directly to one of the drivers, and all the fans can go in parallel with eachother into the 12V power supply. Your final product will look something like this.

DIY COB LED Grow Light

Simple 4 COB DIY LED grow light

Hanging these lights can be a little tricky, and is really up to you how you want to accomplish this. Some people like to put multiple COBs on a large heatsink, but this isn’t our favorite choice as it makes the light a little dense. Remember that we usually recommend 25W per square foot of grow space. But this is usually taking LED watts into consideration. Just like many other grow lights, we’re not running these at full capacity. This 4 COB system is equivalent to a 500 LED watt grow light. It doesn’t have quite the same coverage as a larger light, but you should easily be able to get 5 large plants out of it. Placement plays a large role with these lights. They’re quite dense, so you’ll want to play around with them a little to make sure that you’re adequately covering your entire plant. This style is getting quite popular with the new legalization regulations. Since you’re limited as to how many plants you have, it makes sense that you’d want to get as much yield from one plant as possible. The flexibility you get the a DIY LED grow light is well beyond anything you’d get from

DIY LED Grow Light Projects to Avoid

If you’ve been reading up on DIY LED grow lights, you’ve probably come across guides that show you grow lights you can build for $50, or recommend parts that are way cheaper. We’re not saying that there is no way to cut costs on these projects. You can certainly use cheaper coolers, or salvage something suitable from a computer or other electronic device. But you’ll notice that the bulk of the cost for these projects are the LED lights and drivers. This is the one area that you just can’t skimp out on. We’ve even come across guides recommending that you use architectural LED strip lights for your DIY LED grow light. But these lights aren’t suitable in any way. If you’ve been reading on blog, you know that it’s not just the quantity of light that’s important. It’s both the quality and the type of light that you’re using. Architectural lights aren’t even sufficient from an output perspective. What little light they do output as a very low PAR rating. These guides are, for the most part, designed to be used with herb gardens or to keep your houseplants happy in the winter. If you’re looking to grow marijuana, you simply can’t afford to build an inefficient LED grow light.

Ideas?

See a plan online that we haven’t covered? Drop us a line in the comments. We’ll let you know what we think, and add it to the list if there is something we’ve missed.

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