The alternatives to Mylar are multiple, and I guarantee you, any of them will be a better choice than Mylar. The problems with Mylar are multifold, here are just a few of them while Mylar is a highly reflective material, it does not reflect light evenly at all. It tends to pool light onto the surface of the Mylar, and then reflect that light in a narrow beam of light, directing the product of two square feet of reflection onto a two inch square spot amongst your plants; often resulting in crispy leaves, or a crisped marijuana plant. Crisped plants are no fun at all, they are difficult to resuscitate, if you can at all. Mylar is pretty notorious for crisping some of your ganja girls.
While not inexpensive, Mylar acts like a cheap material in the marijuana grow room
Mylar is not the cheapest material out there, I but in the grow room it is a cheap and non-durable material. Mylar is basically paper, coated with a surface that reflects light highly. It is about 10 steps up from aluminum foil, and acts much like aluminum foil would act. It tears incredibly easily, is not easy to clean at all, and is prone to crinkling and crumpling far too easily. Every little crackle or crumple Mylar gets adds to its unfortunate tendency to pinpoint reflected light, thus adding more problems for you in the grow room. A highly crumpled Mylar surface is just about as good as useless, and should be thrown away. Mylar is also a highly flammable material, and has several MSDS devoted to its flammability and instability.
Not a re-usable marijuana grow room resource at all
Mylar is not an easy surface to clean; rendering it more expensive than materials that can be cleaned and re-used. Sure, you can clean it if you have the patience, and are willing to forego a whole of additional crinkles and crumples in the surface. Once Mylar has reached a certain amount of surface dinks and dings, you should just throw it away, for most people that amount of surface blemishes occurs the first time they try to clean it. Do yourself a favor, drop some money the first time around, and buy Foylon, or Orca grow film, or a Permaflect Grow Film. There are plenty of alternatives to Mylar, and they’re worth it in the long run.