With advancements in technology moving at an incredible speed in modern times it’s often overwhelming to someone just taking up the hobby and even more so when trying to figure out which is the best to get for you. Hopefully after getting through this light article you will have enough information to get you started or at least give you an idea of which light is best for your specific requirements .
First let’s discuss the different options and the cons and pros for each lamp.
Types of Lighting
HID lighting is high intensity discharge. This refers to Metal Halide (MH) and High Pressure Sodium (HPS) most often. HPS is the second most efficient light source and has been used in the growing lighting and greenhouse industries for years. They work very well, put out a lot of light, and even more heat. I’ll go over coverage areas later, but HPS and MH lights can cover a lot more area from a single point source than any other lighting type. That is something to keep in mind if you are running a commercial grow operation or have a very large flowering room.
CFL and Tube Fluorescents
Compact and Tube Fluorescent lights are used extensively for growing. They are cheap to purchase, widely available, produce little heat, and have a wide range of color temperatures.
When using CFLs, you can place them very close to your plants (within 5 to 10 CM) due to their low heat output. This helps the light penetrate deep into the plant and increase photosynthesis. Be careful about using a large portion of CFLs in a small confined space. While they put off a small amount of heat, placing large amounts in a confined space without proper ventilation can cause the heat to rise rapidly. Fluorescent lighting is not as efficient as HID or LED lighting, so as your grow area increases, the energy inefficiency causes a greater problem.
Light Emitting Diode (LED)
LED lighting is the newest form of lighting and has gotten a really bad rap for the most part. LEDs have come a long way over the past few years. Everything we thought we knew about lighting and what produced more light and what grew plants better is out the window when speaking of LEDs.
First, the measurement of lumens that we have all gone by for decades only applies to a very small portion of LEDs, those that produce white light. Because lumen is a scale based on brightness to the human eye, color LEDs have a very low lumen count.
Radiant Flux is the measurement used by designers when attempting to make panels and get a certain percentage of each type of light. The photoreceptors in plants use different wavelengths to perform different functions. This is the main reason that LEDs got a bad rap over the past 5 years or so. When panels first started coming out they only had 2 colors 630nm red and 480nm blue. While this will grow plants, it is missing a lot of the key elements that the plant needs to perform to its full potential.
As companies (and individuals) started testing these LEDs to grow, they noticed this. Soon you could find lights with 4, 5, 7, 11 and even 15 band LED grow panels. The results started to improve but the bottoms of the plants were still not producing very well if at all.
Then secondary optical lenses were more increasingly used to improve penetration. Most companies have learned that hitting wavelengths for accessory pigments and adding these lenses finally made LEDs more suitable for growing. I want to point out that it was the MMJ/Cannabis growers that performed the large amounts of these tests and drastically improved the industry.
LEDs are the most energy efficient form of lighting, produce the least amount of excess heat, and have the highest lm/w rating of any lighting type. The area where LEDs fall short is in coverage area and penetration
Which Lighting system to use?
Each grow room and grower is different. I’ll be the first person to tell you that I cannot give information that is one size fits all. The wants, needs, and requirements for your grow room will be different from mine or someone else’s.
The first thing we need to think about is what kind of light we are going to use. I’ll cover the basics here. There are a few things we need to cover before we get into lighting systems.
The first is color temperature.
Kelvin (K) is the standard rating system for point source white lighting. The sun has a color corrected temperature of ~6500K on a normal overcast day and ~ 22,000k on a completely clear day. This number varies greatly depending on a number of things like: cloud cover, latitude, humidity, and other atmospheric conditions. The more blue the hue of the light the higher the color temperature will be. Likewise, the more red hue it has the lower the color temperature. This rating type works well for most single point light sources, however, it does not work for single color LED lights.
Now let’s get down to the information that everyone really wants. What type of lighting should I use? How much should I use? How far away should my lights be?
The type of lighting you choose will be based on the area you need to cover, the amount of ventilation you have available, and the amount of money you want to spend. We have already covered the basics of each lighting type. Let’s take it a little farther this time.
Cost is a major factor when setting up a new grow room or expanding a current set-up.
CFLs and tube fluorescents are cheap to buy and cheap to replace bulbs (which needs to be done every 4-6 months).
HPS and MH systems can cost quite a bit more to purchase, starting at around R2000. The bulbs can be pricey as well, costing up to R900 or more each.
LEDs are by far the most expensive. Panels can cost as much as R45 to R55 per watt (and more for some companies). However, the “bulbs” last for as much as 5 years without any noticeable degradation. The “driver” or power supply (called ballast for HID lighting) will be the first thing to fail with an LED system. If you are considering LEDs, make sure the company has a good service/repair policy.
Remember that heat and ventilation will play a role in this selection as well. If you do not have any venting available for your room, HPS/MH lighting is NOT for you. Likewise, if you have heat problems in your grow area you will want to avoid HPS/MH lighting as well.
So how much do I need Matt?
The following is a MINIMUM light requirement for productive growth in the flowering stage:
CFL: 65 watts per square foot
HPS/MH: 50 watts per square foot
LED: 35 watts per square foot
Hopefully the above article has given you a starting point in your search for the best grow light for your needs. Next time I will discuss some more intimidating terms like lumens , LUX, PAR and a few other more technical aspects of lighting.