Almost all indoor cannabis cultivators will agree that reflective materials are an essential component of a high-performance grow-op. Sunlight is definitely the best source of light. But when you grow cannabis indoors, you must use artificial lights. And if you don’t want any of that light going to waste, you better invest in reflective materials. Using the right kind of reflective material can increase your yields by as much as 30% according to most grand master growers. The wrong materials will burn holes in your plants and might even reduce your yield. Here’s what you need to know.
A grow tent is an off-the-shelf, self-contained cannabis garden covered wall to wall and floor to ceiling in highly reflective material. Most modern grow tents are available with various grades of Mylar. Recently, some manufacturers like GreenQube have developed a special white Mylar lining called Spectrax, designed for maximum LED reflection. Secret Jardin has also expanded their range to include grow tents lined with Orca grow film.
White, plastic-lined grow tents have become obsolete, and very few manufacturers still use this material. Shiny silver interiors are still the most common and probably the best value for money. For the average ordinary decent home grower, a grow tent lined with standard silver Mylar lining is really all you need.
REFLECTORS FOR GROW LAMPS
Dimpled or hammer style reflective hoods are considered the best for HID lamps. The glossy, smooth finish reflectors just don’t perform as well; the hammer style diffuses the light more evenly, and once upon a time, sheets of this aluminium were used in DIY grow-ops.
Bigger is always better when it comes to reflectors. Narrow little cool tubes won’t reflect nearly as much light as an extra long and wide adjust-a-wing. These days, you can even buy add-on kits to make some models of hoods wider if you plan on growing a larger number of plants.
LED units do not require a reflector as the diodes themselves are constructed from a highly reflective material. CFLs can be used in most common HID hoods, so long as they have an E40 screw fitting. Although, due to their added weight, it’s really only a viable option for the sturdier and heavier HID hoods.
Rolls of Mylar are probably the best option for lining the walls of a custom grow room. It’s not as pricey as it used to be and reflects as much as 90% of the light. Every decent grow shop will have rolls of Mylar available. This material was actually invented by NASA. What more proof do you need that it’s awesome? Just make sure you keep it flat and avoid bumps and bubbles, or you might create “hot spots” by accident.
ORCA GROW FILM
Orca grow film is one of the latest reflective materials, and usually the most expensive. That’s provided you can find a grow shop that sells it by the roll. It hasn’t really become very popular in Europe yet. Although, it is some very high-tech fabric that utilises a crystalline microfibre to boost reflection into the 90%+ range. Again, bubbles and bumps must be avoided when laying this over walls. Most growers will use Velcro to make sure it’s nice and flat.
Cheap and cheerful rolls of white plastic sheeting can get you into the 80–90% range. But the downside is this material could melt and often starts peeling off the walls if the grow room gets too hot. It’s not the best reflective material, but if you’re on a budget and have a large room to cover, it’s a decent option. This reflective sheeting is not hard to find and almost every grow shop sells it by the roll on discount these days.
Matte white paint is probably the best option if you have limited funds and a large grow space to cover. It’s almost as good as all the above options, typically with 80–90% reflectivity. The only real drawback is it’s labour-intensive to apply. You will have to buy some rollers and brushes and apply two coats of paint to ensure you’ve got total coverage. Just make sure to let it dry and air the room out for a few days to vent the paint fumes.
As popularised by Ricky from Trailer Park Boys, this is a pretty crude reflective material and really not a great idea. Aluminium foil applied dull-side facing out only offers about 50% reflectivity. Worse, it’s incredibly fragile and has a reputation for creating hot spots, no matter how perfectly flush against the wall you manage to stick it. This is one reflective material to avoid.
Straight from the big book of bad ideas is using mirrors to reflect light. Just don’t do it. Mirrors might look like a viable option, but they just don’t do a very good job at all. Hot spots are virtually guaranteed, and if you break one, it’s 7 years bad luck. No grower needs a hex on the grow-op.