Maximizing Indoor Grow Lighting Effeciency

[G-Dog]

This thread is about maximizing the efficiency of your grow room lighting.

I did not specify a lighting type for this thread as many of the same rules apply in maximizing efficiency, regardless of the lighting type. However, there are limits to what you can do. For instance, I would not use foamcore to reflect light as much in a HID grow operation as I would with CFLs, due to fire hazard.

In growing marijuana indoors we want to simulate outdoor conditions as close as possible. It is very difficult to match the available lighting intensity of the sun, but we make up for that in our control. We can control the heat, lighting intensity, humidity and feeding. We have all seen indoor bud that rivals that which was grown outdoors.


Something that is often talked about in these forums is lighting. Some folks hang a powerful High Intensity Discharge (HID) lamp and call it good. HIDs come in various compositions with a couple of the most popular being Metal Halide (MH) and High Pressure Sodium (HPS). Others may not want the unwanted heat and associated heat signature that comes with growing with HIDs and they have opted to use the less expensive, more energy efficient, and cooler Compact Fluorescent Lights (CFL). My experience with CFLs has been very positive when all things are considered. Although they are not as powerful as HIDs and require more fooling around, they are an inexpensive option that creates less heat, and therefor attract less attention from the police and other unwanted parties. To me, CFLs represent the future of indoor marijuana growing.

 

[G-Dog]

Re: Maximizing Indoor Grow Lighting Effeciency.

Opinions vary on what the idea lumen per square foot requirements are for growing marijuana. One could say that you want a lot of light and be correct. Getting light in the right spot is also important. Color of light, in my opinion, is up for debate still. I have not had conclusive proof that changing your lighting frequency or color helps, but that is sure to cause an argument among our peers, whereas saying you need a lot of light is a safe topic and one that I prefer to stay focused on.

Lighting intensity falls off exponentially by the distance, that is a law of physics. The law is called the Inverse Square Law and is demonstrated by the following diagram.

Understanding the exact meaning of the above diagram and formula are not as important as understanding that if your lighting is adequate at one spot, moving it further away renders it less effective. This comes into play even more so when you employ reflectors. If light has to travel in one direction and then be reflected back the light losses intensity in both directions. However, lumens in the grow operation are additive and anything you can do the capture as much light as possible and add it back to the plants is beneficial.

 

[G-Dog]

Re: Maximizing Indoor Grow Lighting Effeciency.

There are many reflective mediums available from Mylar to Foamcore. Flat white surfaces create a more even level of illumination were metal foils seem to create uneven light levels and hot spots. Another thing to consider when using metal foils is that they conduct heat and electricity and are easily ripped. I generally try to steer away from foils, but have seen foil combined with insulation that is sold in rolls like blankets in home stores that were fine. They can be easily stapled to frames, duct taped and you can use velcro for an opening.

 

[G-Dog]

Re: Maximizing Indoor Grow Lighting Effeciency.

I have been using a foam core lately that is sold in a major discount store. It is less than a quarter inch thick and sold at this store in 22 x 36 panels for $2-3. It consist of construction paper bonded to sandwiched with styrofoam center. It is fairly durable while being easy to cut with a box knife. It can be stapled to a frame like the insulated foil or used without a frame. I have cut hole and mounted computer fans directly to the panel. I have also bent it into arcs for creative light reflectance. I have fallen in love with the this material in the past couple of years.

Below you can see a photo of some I used in my mother chamber. It is a laundry hamper with CFLs, foam core lined, and you can see where I cut a hole in it for a computer fan.

Below is some stock material as it is sold.

 

[G-Dog]

Re: Maximizing Indoor Grow Lighting Effeciency.

Although light loses intensity from being reflected, all the lumen are additive. If you can bounce the light back in that is better than not. Anything white is good for reflecting light, and second to that are polished metals or foils. I have even been known to put an extra handful or two of Perlite on top of my soils for the reflectance. I hope more people come in with ideas on how to reflect light or maximize the efficiency of lighting.

 

[G-Dog]

Re: Maximizing Indoor Grow Lighting Effeciency.

Here are some photos of my grow in the closet under the stairs. The area was wider than I needed and would send light out that I wanted to keep. So I built a walled in area of the area with the foam core. The floor was covered in foam core as well. Notice that I used duct tape to keep it together and the walls supported themselves.

In this shot I show one of the methods I used to keep stray light inside the closet with an extra piece of foam core. I also put door seal material around the door. The room didn't let any light out.

Apollo 11, F-13 x Apollo 11 and F-13 x Apollo Trip

 

[cflgrow]

Re: Maximizing Indoor Grow Lighting Effeciency.

Not a bad setup at all, G-Dog!

The only thing you missed was the lumen ratio of HID's. If you combine CFL wattages to equal a 400 or 1000 watt high intensity discharge light, the sum of the lumens is way smaller than the HID light.

Essentially, 400 watts of small CFL bulbs has a much lower light intensity than a 400 watt metal halide light. That's why I switched over. From what I'm counting, you're running about 15 lights or so. In my opinion, if you plan to expand much more, you might want to try a MH or HPS with a good reflector (or a light mover).

 

[G-Dog]

Re: Maximizing Indoor Grow Lighting Effeciency.

Thanks CFLgrow.

Your name is CFLgrow, but you advise to use HIDs?

I have used HIDs in the past, and they worked fine. I have decided that since my needs are so small that I can get by with CFLs for the time being.

The purpose of this thread is to find and talk about ways to maximize lighting efficiency.

I was just in Walmart today and seen the those foam core panels for $2.68. They call them Foam Boards there.

 

[Brett2theMax]

You should look into Panda Plastic or its equivalent counterparts. Its a great product, you can clean it unlike mylar. My bro just set up his room and we completely wrapped the room in it. This is how I'm setting up every room until the day I die. Once you have all the seams taped up its like a lab environment in there, only air coming in where you want it to enter from the source you choose, and air only exiting through where you choose. Its a pretty sound investment.

 

[G-Dog]

You should look into Panda Plastic or its equivalent counterparts. Its a great product, you can clean it unlike mylar. My bro just set up his room and we completely wrapped the room in it. This is how I'm setting up every room until the day I die. Once you have all the seams taped up its like a lab environment in there, only air coming in where you want it to enter from the source you choose, and air only exiting through where you choose. Its a pretty sound investment.

Thanks Brett, I just checked them out. That is a great point. There are many reason's that a person would want to do a deep clean (scrub walls) of a grow room from insects to powdery mildew.

 

[Brett2theMax]

Exactly. All we did was clean/disinfect the room then wrapped it in Panda. Every single seam is taped too so the only places that any pests could come in is with you. All the inlet air is filtered as well as the exhaust. Temperature and Relative humidity are much easier to control and keep stable at that point too.

When a room is sealed like that you can really dial things in too. By calculating Cubic Feet of the room you can choose how many times you want a full gas exchange in the room to happen with a little bit of simple math. By knowing when air exchange happens you can run your CO2, humidifier, dehumidifier, and/or A/C unit to keep the environment as stable as you can.

Growing Mono-crops like we do it is imperative that we establish the optimal environment from birth of the plant and sustain it all the way through out the duration of its life. I was just talking to a friend today about my plants asking why the stems of my leaves are purple, some one said N def. But he quickly interjected that it could be a range of things down to my oscillating fan placement in the room. These plants are hearty but when you start to pay really close attention to the details of each plant you quickly learn to get everything perfect is not easy.

 

[G-Dog]

Exactly. All we did was clean/disinfect the room then wrapped it in Panda. Every single seam is taped too so the only places that any pests could come in is with you. All the inlet air is filtered as well as the exhaust. Temperature and Relative humidity are much easier to control and keep stable at that point too.

When a room is sealed like that you can really dial things in too. By calculating Cubic Feet of the room you can choose how many times you want a full gas exchange in the room to happen with a little bit of simple math. By knowing when air exchange happens you can run your CO2, humidifier, dehumidifier, and/or A/C unit to keep the environment as stable as you can.

Growing Mono-crops like we do it is imperative that we establish the optimal environment from birth of the plant and sustain it all the way through out the duration of its life. I was just talking to a friend today about my plants asking why the stems of my leaves are purple, some one said N def. But he quickly interjected that it could be a range of things down to my oscillating fan placement in the room. These plants are hearty but when you start to pay really close attention to the details of each plant you quickly learn to get everything perfect is not easy.

That is a fact Brett, but for many of us it is just a hobby. We challenge authority and create an environment that is supposed to replicate the perfect home for our specific strain.

I have never thought of purple as a characteristic of bad health in the stems. Not that I know one way or the other, but I had always thought that the leaves were the best indicator of health. And in that case I know that some mutations occur that many try to capitalize on that include color.

Enjoy your hobby and thank you kindly for the contribution.

 

[oldthumber]

Thanks Brett, I just checked them out. That is a great point. There are many reason's that a person would want to do a deep clean (scrub walls) of a grow room from insects to powdery mildew.