Dense, sticky buds are the result of abundant energy, both in terms of nutrients and light. Lighting systems can be very complicated, because it is. There really are many things which either make or break a light. Especially the LED varieties can seem like they are good, but in reality, they are emitting garbage light. It’s important to know what you’re facing before spending a few hundred on a lighting solution though, so this grow tent with lights guide is important!
Having the proper light coverage, intensity, and distance will provide you with a proper yield. There are so so so many things to consider when buying a light, let me just run you through some of the biggest ones:
- wavelength of the light
- wattage draw
- lumen output
- heat output
- how close it can hang to the plant
There are many different kinds of light, and each one has its own peculiarities. In this section, we will go into how to find the perfect light for your grow, big or small. It is very easy to get confused in trying to find the best light, but I hope this will shed light on your search.
Light Source Options
Now that you understand the criteria by which to select a light, it’s time to show you the selection. I tried to make these options as clear as possible, so you can make an educated choice. There are many different types of light sources, but usually each application will ask for a certain kind of light.
Let’s start off with the popular sources, and work our way down.
Light Emitting Diodes – LEDs
Especially in recent times, LEDs have blown up in popularity. They are pretty cheap to manufacture nowadays, are extremely efficient, produce a good range of light, and produce practically no heat. A lot of people have the misconception that marijuana plants like the intense scorching of an HID bulb, but that’s not necessarily the case.
Again, it’s all about wavelength, quality of light, and LEDs are very good nowadays at delivering a good array of light. There are a lot of really, really crappy boards out there, even on Amazon, so be careful! I have a few favourites that I have bought time and time again, and I go over them in my light buying guide.
These things are just sick. I’ve got more than one – that’s how much I like it. Many other panels will have a plastic enclosure, crappy driver, and cheap Chinese LEDs. This one has a metal base, Samsung’s Quantum Board diodes – some of the best in the world, and a Mean Well driver – also top notch. The entire surface is covered in a specialised rubber coating which repels water and keeps it safe. There are 4 different kinds of diodes, each emitting different wavelength ranges. Look no further for the top LED panel.
If you’re going to get an LED board, try to see if the manufacturer displays a wavelength output graph. If it is concentrated in one place, and seemingly drops off in every other frequency, it’s not a good all in one solution. You need one which either offers a broad frequency range, or can be switched between the two.
The heat output, efficiency, and durability are three big differentiating factors for the LED. Heat output is virtually non existent, so you can cram a bunch of power into a small space, or not have to run a bulky, energy draining AC in the summer.
Not wasting so much energy on heat also creates much improved efficiency. For the same wattage draw, you will get a much higher joules per watt rating – more efficient. This could play a part if you are leasing and don’t want to rack up your landlord’s bills, or your own for that matter.
With the reduced heat also comes increased lifespan, especially if you include some kind of active cooling technique. Some LEDs will have fans incorporated into them; mine did not, so I made my own solution. It’s easy to keep LED panels cool, so don’t let them get hot! They will last so much longer if adequately cooled.
All in all, while you might end up spending a bit more up front for LEDs, it’s going to pay off in the long run. The higher efficiency, lower heat output, and lower load on your electricity is fantastic for long term operating. I highly recommend LEDs as a key part in your grow lighting solution. I personally have a 1000W LED next to my 600W HID, and it’s prime.
High Intensity Discharge – HIDs
If you are going to have a dense thicket of bush, or you just want to go all out balls to the wall, you want an HID. No matter how gnarly your LED array is *cough* Spider Farmer SP1000 , I honestly don’t think there’s anything like the pure, vibrant spectrum which come from a well made HID bulb.
There are a few big reasons you might want to chose an HID, including more intense light penetration, sun-like wavelength replication, and more tried and true reputation. Many growers only use these bulbs because they think that LED diodes can not match up to their sun-like light, and immense light penetration.
On the other hand, they draw a whole bunch of juice from the wall and radiate crazy amounts of heat. If you’re using an HID, it’s going to likely cost more money to operate over the long-term. Also, when you count the ballast and reflective hood, they can be as expensive as LEDs, or sometimes more so.
That being said, don’t let it dissuade you from trying an HID setup. I have one in my main tent and it’s fantastic for making full, dense nugs. It’s mostly up to whether or not you think it would work well in your setup, and if you’re interested in trying it.
However, there are also a few downsides to the HID option, most notably a higher barrier to entry – it’s a more complicated system, much higher heat output, and much higher wattage draw.
This is a nice little HID growing package for a new tent with grow lights setup. It’s got both a High Pressure Sodium and a Metal Halide bulb. The former is for flowering state and the latter is for vegetative state. The ballast has a dimmer switch which is really useful in the times that you need it, and it does happen. The straps have a ratchet mechanism so that you can easily adjust the height. Pretty standard setup, performs well.
Lighting Ballast for HIDs
Although your LED panel will have all kinds of electronics built in, your HID bulb will need an external dedicated ballast. This is a device which modulates the current passing into your light, and keeps it in a specified range. This is because the HID bulbs are very sensitive, and so any significant deviation would likely cause damage.
There are some cheap options out there which get the job done, but you might not want one of those. Mine has a dimmer feature, which I’ve found to be extremely useful. I can adjust my wattage 100%, 75%, or 50%. This is great for when things get too hot in there, or when I just want to tone it down a little bit.
However, if you don’t need this option, maybe a cheaper model will suffice for you. Be careful though, this is a sophisticated electrical unit, I don’t know if skimping on it is wise. Also, don’t mount it inside the tent – it gets humid in there, keep it outside somewhere. Make sure it gets adequate air flow, and is secure, and you should be golden.
Light Reflectors for HIDs
As you might have noticed on some pictures, an HID bulb must be surrounded by a hood to work properly. If it was unguarded, much of the light would be lost, so the hood serves to concentrate the rays. There are many kinds of hoods, but the most common is the bat style, which is basically just a piece of aluminium bent to the rough shape of a bat’s wing.
There are other, more sophisticated hoods which serve a cooling purpose as well. Like I mentioned, HIDs get really hot, and so it’s good to sometimes evacuate that heat right at the source. A cooling hood rushes fresh air right against the bulb, and carries it straight out of the tent, not to be mixed up with the rest of the tent’s air.
This is a very good solution if you want the intense performance of an HID, and the cool operation of a LED. It’s going to cost you some cash, and a decent amount more setup time, but it’s a really good solution to what can be a devastating problem. Plant’s don’t grow well under heat above 28 degrees Celsius (82 F), so consider this route if you have heat problems.
Wattage per Square Foot
So, with the heat in consideration, the square footage of the grow space is the most important thing. It must be noted that one watt of LED light is not the same as 1 watt of HID bulb light, so I will have two different tables, one for LED and one for HID.
From what I have gathered from various sources – books, experience, online, you generally want 40-75 watts per square foot. If you want to go really hard, you could do 100 watts per square foot. Remember that 1 square meter is around 1 square foot, so for msquared, you need 400-750W.
Me personally, I have a 4×4 tent with a 600W HPS, so that 16 feet squared – around 1.5 square meters. Therefore, my wattage just reaches into the lower range of this scale.
Based on this, I have prepared the following chart:
|HID – High Intensity Discharge Bulbs||LED – Light Emitting Diode|
|Wattage||Footage Cover||Plant Cover||Wattage||Footage Cover||Plant Cover|
|300W||5 ft sq.||2 Plants||150W||5 ft sq.||1-2|
|400W||7 ft sq.||4 Plants||200W||8 ft sq.||2-3|
|600W||10 ft sq.||6-8 Plants||300W||11 ft sq.||4-5|
|1000W||17 ft sq.||8-10 Plants||350W||15 ft sq.||6-8|
And here is a version is meters squared:
|HID – High Intensity Discharge Bulbs||LED – Light Emitting Diode|
|Wattage||Footage Cover||Plant Cover||Wattage||Footage Cover||Plant Cover|
|300W||.8 m sq.||2 Plants||150W||.5m sq||1-2|
|400W||1 m sq.||4 Plants||200W||.8m sq||2-3|
|600W||1.5-2m sq.||6-8 Plants||300W||1.1m sq||4-5|
|1000W||2-3m sq.||8-10 Plants||350W||2m sq.||6-8|
As you can see, the LED world is vastly different than the HID world. Although it draws a lot less power from the wall, the effects are also a lot less. However, it’s still a lot more efficient, especially when you get to the 350W LEDs, which are almost functionally equivalent to a 1000W HID. Note that the wattage mentioned for LED is not the output wattage, but the input wattage, which is usually a lot lower.
Wavelength and Light Quality
Depending on the stage the plant is in, you will need to adjust the kind of light the plant consumes. Just like changing to a different set of nutrients during bloom phase, the light must also be changed. When you change the nutrients, it’s mostly the distribution of macro molecules which changes.
A light on the other hand, changes wavelengths depending on the phase of the plant. HID bulbs are really good at producing a really rich spectrum of light, you can depend on them. There are two main types of HID bulbs you need to know, the metal halides, and the high pressure sodium.
Metal Halide (MH) Bulbs
Metal halides produce a really intense white light, up to 5500 Kelvin in terms of the colour temperature. This light is really high quality, the plants love it during vegetation stage. This is the light which plants expect during the peak summer months. It’s in the blue range of electromagnetic radiation, as compared to the red hue of a high pressure sodium bulb.
High Pressure Sodium (HPS) Bulbs
Compared to the metal halide, HPS bulbs produce light with a noticeably orange or yellow tinge. This is exactly what plants expect to see when the sun is drawing out further and further from the Earth during harvest season, making a more and more red wavelength. This is perfect for flowering stage of the plant.
Light Emitting Diodes (LED)
LEDs are a little bit different for a variety of reasons. There are many panels which will allow you to change the temperature of the light. Usually, the knob will turn from veg to flower option, or vice versa.
Likewise, there are some diodes and drivers which produce a really narrow wavelength spread. This is not healthy for the plant, because it’s like focusing in on just feeding one particular nutrient only. On the other hand, well made LED boards will feature a nice full spectrum, which you could use for the whole cycle.
Some LED boards will feature many different kinds of diodes. Some of them will output infrared light, others will focus on ultraviolet, and still others will be aimed at the middle of the range. It’s nice to get a robust LED panel with a good spread, it will result in healthy flowers.
At the end of the day, it’s important to make sure your wavelengths are on point. At least make sure that you have a diverse spread of wavelengths. If you are using HID bulbs, definitely get both varieties, and swap them out when you switch cycles. If you get an LED panel, either get one where you can switch wavelength ranges, or get one which will always output a broad spectrum.
Keep in mind, your buds will not do a good job of getting dense if you do not give it enough red shifted light. It’s very important, especially during flowering, to make sure everything is perfect, and this is one thing to consider.
Lighting Cycles and Changing Growth States
When growing a normal plant – not autoflower – you will need to manually adjust the cycles of light to engage the flowering state. In the real world, the days start to get colder, and the nights longer in the fall, right? This environmental stimulus tells the plant that winter is coming, and that it should engage it’s late stage growth cycle – blooming.
Remember when I detailed how red spectrum light is for bloom, while blue spectrum is for vegetation? Well think of that as half the puzzle of letting the plant know it’s time to bloom, and the lighting cycles as the other half.
I like to let the tent shut down, and then wait until just before the lights come back on – so the bulbs are cool. Then, I remove my metal halide bulb, and replace it with my high pressure sodium. At the same time, I change the programming of my lighting controller. These two steps together give a definitive signal to the plant – it’s time to make some buds, girl!
Lighting Cycles for Vegetation State
So this is the lighting mode you will initially start off on. From all the resources I’ve seen on the internet, and my own research, 18 hours on, 6 hours off is the cycle for vegetation state. This gives the plant plenty of quality light time, but also a decent amount of time to recooperate and actually do some growing. I hear that most real structural growth happens while the plant is asleep. I don’t know how true that is, but sleep definitely does help make healthy plants.
Lighting Cycles for Flower State
Following the thought process that plants expect days to get shorter towards fall time, we need to reduce the amount of time the lights shine to induce flowering. The perfect timing for flower state seems to be 12 hours on, 12 hours off. I think that’s really pushing it, and so I’ve never heard of anyone trying to squeeze more on hours during flower state. If you leave the lights on too long, it might stress the plant, confuse it. You’re better off sending a clear signal that it’s supposed to be making flowers, albeit at the cost of producing less light.
Lighting Cycles for Autoflowers
Autoflowers are a different story all together. Because they’ve been genetically modified to automatically switch to flower state after around 1.5 – 2 months – regardless of light cycle, you can squeeze some more daylight into them.
I know a few people who have ran a whole autoflower growing cycle on 24 hours of light, and it does turn out pretty decent. I’ve heard mixed things about it. At the end of the day, I don’t recommend it, because I think all biological things need rest to properly heal and develop.
However, when I grew autoflowers, I found 20 hours on, 4 hours off to be a really nice middle ground. Not only do the plants still get sleep, but you can squeeze 2 additional hours during veg, and 8 more than normal during flower! That’s the upside of growing autoflowering bud, the exposure to more light.
My first tent was a 4×4, with a 600W HID inside. During the summer months, I peaked out at around 40 degrees Celsius (104F) – way too hot. I didn’t know just how much heat this bulb produced, and so I slacked on the ventilation, and got a horrible first yield. This is why it’s important to consider the heat output of your lighting solution.
Some people will need to be more weary of the heat restrictions than others. For example, if you’re growing in a shed in Arizona, unless you want to be running two ACs at once, you don’t want an HID. Get a nice LED array, and you’ll be good to go.
On the other hand, if you can manage the heat output, and would prefer the more intense light penetration, and HID would still be a good choice. If you’re going to get a high intensity discharge bulb, just make sure you’re getting proper ventilation.
Conclusion of Grow Tent with Lights
There’s certainly a lot of information here, and it can be overwhelming, but at least you can reference this content some time in the future if you need. This should get you a good understanding of how to set up a grow tent with lights. Again, mind the heat, the power draw, the lumen emitted, and the kind of wavelength. If you consider those things while looking for a lighting solution, then things will work out.