When you are growing cannabis indoors you are creating a self-enclosed environment by providing ventilation, lights as well as soil, and nutrients that promote plant growth. Usually grow lights are the single most expensive thing any grow room needs. That is because the light is cannabis plants’ main energy source and without proper light, there will be no growth and no bud production.
Over the years HID light has become very efficient as well as cheap and there have even been some newcomers like fluorescent light and LED diode lights that can grow cannabis plants. But what if I told you that you can get up to 30% more light from your existing light source without the need to install new lights and without more electricity costs?
If you are intrigued then you are not alone because many growers when first starting out find information about grow room reflectivity and are pleasantly surprised when installing a reflective film or painting you grow room white can increase the overall growth and yield of your plants growing in that room.
When autoflower plants are growing outdoors then they get as much sunlight as they need and it does not matter if they are a few centimeters closer to a light source and if the surrounding environment reflects light. But indoors when growing with artificial light sources every centimeter of distance between a light source and your plants will count and in your grow closet or tent is not reflective some light will be absorbed by those walls and turned into heat but that obviously is not efficient.
That is why growers usually use various reflective materials to reflect all that light back to their plants and to create the most growth possible from their artificial light sources.
Here is a list of all the possible reflective materials that you can use in your grow room.
Usually, it depends on your growing conditions and your budget what materials will you be able to use but most of these will reflect light better than nothing and that is a start!
Mylar is maybe the most common grow room reflective material that usually comes in 1 mm or 2 mm thick sheets and reflects more than 95% of the light that hits that surface. This material is fairly inexpensive and it comes either in flat roll form or pre-made sheets that you can stick to your walls.
There are various versions of this material that you can get but the best ones are those that have some kind of a texture that will help with light reflection and will stop wrinkles from forming.
Regular mylar sheets are usually very fragile and any damage to them can result in bends and folds that tend to concentrate light in one spot and if that happens near your plant then it can get heat damage.
Foylon is a more durable version of mylar that has a reinforced laminate coating and will not tear or crease that easily. Foylon is a bit more expensive than regular mylar but it can be used multiple times and if you manage to make it dirty you can simply clean it without creating folds or bends.
C3 anti-detection film is another variant of Mylar and it is a material that has been specially designed not to let any heat trough. Because of that it can be a great addition to grow rooms that are constructed in cold climates. But you have to be careful in hot climates where you will need a lot more ventilation to counteract that heat as well as those light reflection properties.
The single most inexpensive and easiest method of creating a great reflection surface is to get a flat white paint with as much titanium oxide as you can find.
White paint is used in larger as well as smaller growing spaces and it can reflect up to 80% of the incoming light and for such a cheap price it is a great solution.
If you are using white paint make sure that it also has additives for mold resistance as that will ensure your grow room will stay sterile and no molds or mildew will form on your walls and on your plants. And before you apply that paint to all the walls I would also advise to first get a white mold resistant primer to cover all those surfaces as that will allow you to create another protective layer as well as will increase your paints reflectivity rating.
Elastomeric paint is another great substitute for simple flat paint. It has a latex additive that makes it a semi-liquid and will allow paint coating to seep into all cracks and even heal itself under pressure and some other mild damages. This paint can also reflect a great deal of light but it will be a bit more expensive and you will need to wait a longer time for it to dry.
Black and white Polymer
The black and white polymer sheets that are also called panda plastic or panda foil is a plastic polymer with one side black but the other side white and this can be a great tool for your gardens light and heat isolation and reflectivity.
Panda plastic wraps come in rolls and you can staple or glue them to any surfaces you want but they tend to be on the expensive side and if you get them too close to your light source they can easily melt.
This option can be great for large-scale sealed grow operations but for small-scale cabinet grows it usually is an overkill and it is too hard to properly attach this polymer to all the walls without cutting it in multiple places.
Emergency blankets are those foil-like things that we all have seen in movies when ambulance workers wrap people in when they have been in cold water or stayed out in cold weather too long. These things are very cheap and they are made from mylar but they tend to be folded up into small packages and they are not completely lightproof because of the thin material.
The emergency blankets can be great to use for temporary grow operations that you will eventually tear down as they are inexpensive and will get bent and folded anyway so you will have to remove them each time you start a new grow.
Aluminum foil that we also know as thin foil is a common household item that we use for cooking and other stuff. Despite that this material looks very shiny it does reflect only about 60% of the light that comes in contact with the dull side and the shiny side is even less reflective.
This foil looks like a great way how to reflect the light but it really is not a great option because this foil tends to wrinkle and crease a lot and all those wrinkles and folds will create an uneven light distribution that can even burn your plants.
Use thin foil only if you have no other alternatives.
Blackout canvas is a product that is used in top of the line grow tents as this is maybe the best material that completely reflects all the light back in your growing environment and does not let any light leak through this material.
This blackout canvas is one of the most expensive reflective materials but if you need to completely light seal your grow environment then this is the way to go.
White bed sheet
If you have no other option then you can also line your grow room walls with white bedsheets as they are quite reflective and easy to work with.
That is why many growers have used this material to line their cabinet grow boxes as well as larger grow environments.
But because these materials are not 100% lightproof they will let light trough and for some that is not acceptable.
Styrofoam that is also known as polystyrene foam sheets is a great and cheap way to reflect some of the light back to your cannabis plants.
These styrofoam sheets can be bought in bulk and are very light so you will be able to hang them to your walls. But be careful and not put them too close to your grow lights because they can melt easily and cause a fire hazard.
You can expect up to 70% reflection but usually, these are just temporary solutions while you can get something much more reflective.
Orca grow film is a special material created for complete light reflection and diffusion and in most cases, it works better than regular mylar or any other reflective material.
Orca film has a snowflake-like molecular structure that scatters the light to all sides and that does not create hot spots and this material also does not let light through.
When installing this material you have to put the white side inwards and the black side outwards so that the light is reflected back to your autoflowers.
Another great thing about orca film is that it has also some anti-mold properties and the company states that it can reflect up to 95% of the visible light spectrum!
The only drawback is price because this material is very expensive and for the beginner grower that is on a budget it can be too expensive!
When talking about reflective materials I also need to say a few words about various grow light reflectors that will direct the light from that light source downwards.
With these reflectors when combining them with reflective materials on all your walls you can ultimately create around 30 to 50% more light directed to your plant. That can be a huge deal as you will not need to increase your grow light count or strength but will create more growth and bud production.