Applying Ag Barrier to the surface for the walls of your grow room is very important, as up to 40% of your total yield comes from the edge and the right wall surface can increase the amount of light those plants receive by up to 30%! Artificial lighting diminishes exponentially with distance, so it is important to “contain” as much of this light as possible and direct it accordingly. Reflective surfaces also help illuminate the lower portions of the garden, providing lower buds with light and heat energy.
To get the best results with your light and walls, it is important to get the walls as close as possible to your garden to ensure the least amount of light is wasted. As a caveat, the percentages provided are only useful as a general guideline, as they present the range of reflectivity of the particular surfaces. The high percentage presents the best possible circumstances for that material (for example a 95% reflectivity rating for Radiant Barrier sheeting would be under ideal conditions – no creases, completely flat, no discoloration, etc).
The best way to determine how well your grow room walls reflect light would be to purchase a light meter and measure your light directly. Then take an opaque board and hold it a few inches off one of your walls with the light meter below the board in such a fashion that the light reflects off the wall and onto the light meter. You can then compare the difference between the two and determine a percentage from those numbers. The closer the two numbers are, the better your wall reflects light. It is important that in both measurements, your light meter is the same distance from the light, otherwise your results will be skewed.
Also important to note is that radiant light energy refers to electromagnetic (EM) radiation with a wavelength between 400-700 nanometers (nm) and radiant heat energy correlates to EM radiation with a wavelength between 800-2000 nm.
Ag Barrier is an agricultural radiant barrier and is the most durable version of Radiant Barriers. It is a 70 gram material with metalized polyester on one side and a polyethylene surface on the other side that can be ordered in white or black. The Polyethylene side is designed to be power washed. The white coating is for those who are looking for a bright finish. The black coating is for those who are applying a blackout material over their plants in a greenhouse application. Ag Barrier is heavily coated with UV and corrosion protection. Ag Barrier is resistant to most solutions, won’t tear or fade, and can be wiped or washed clean.
Ag Barrier is a great solution for growers who are interested in long term use. Though it may be slightly more expensive than Mylar, its durability will more than make up for its cost. It has the ability to reflect about 95% of the light. A good ventilation system should be used in conjunction with Ag Barrier.
One method to attach Ag Barrier to the walls would be using Velcro, as it makes taking it down for cleaning much easier and reduces the risk of tearing, creasing or bending it. If this is used for your walls, you can install flush with the wall or use 1/2″ wood strips to create a dead airspace. The dead airspace will prevent any heat transfer through the wall.