How to effectively hang mylar in a grow room
Firstly, you should decide whether you truly want to use a reflective mylar or stick with a matt white painted wall, read our guide on mylar vs white paint here to help decide. If you are set on using Mylar then you will still get fantastic results but it is imperative that the mylar is installed in such a way that there are no kinks, folds, or creases anywhere in the sheet – which is easier said than done.
There are a couple of different ways that you can hang your reflective mylar onto the wall but to do a smooth job it is much easier to have a second person around to help you. Here are the different ways to stick mylar on to a wall.
Thumb tacks come in a whole range of shapes and styles but the most common are the flat golden-headed tacks as seen above. These sharp little tacks will pierce through the mylar and into most walls with ease. If the wall is solid brick with no plaster (as often seen in a loft space neighboring wall) then thumb tacks will not work as they will not be able to fix into brick.
Sticky Backed Velcro
This method is used by some people but it is not the best option as lining up both parts of the velcro on the wall and mylar makes things a little more awkward than using other methods such as tacks or tape. It is a good idea to add a little super glue as sometimes the sticky bags are not that strong. The positive of using velcro is that it will work all on types of walls unless there is loose paint etc.
This is a quick and easy way to install mylar and again it will work on all types of walls including straight brick. However, when it comes to taking the mylar down the sticky adhesive will take a lot of work to remove from the wall depending on how much of it you use. If you are attaching mylar to temporary sheets of wood such as MDF then spray adhesive can work very well.
Some adhesive sprays can be very toxic and give off dangerous gasses that will harm your plants. If plants are in the room then it is best not to use any adhesives.
Duct tape is one of the most common ways to attach mylar to a wall as it will work on all substrates and it is quick and easy. However, when the duct tape is removed it will most likely pull paint off the wall so some redecorating may be involved in the future. Low-quality duct tape can also unstick after time due to the higher grow room temperatures and wind from fans. It can be a good idea to use plenty of tape to make sure the mylar doesn’t fall down in the future. Mylar duct tape is also available instead of black duct tape.
To ensure a good fixing some people like to place a few wooden roof battens on the wall either vertically or horizontally. You do not need many and they can be glued, nailed, or screwed to the wall. After the battens are fixed (see above for an example) then mylar can be attached straight to the battens using thumb tacks, adhesive spray, or a nail/stapler gun. Be sure to check the space between the battens is not wider than the mylar!
Plywood/MDF Movable Sheets
Using plywood with mylar has some huge advantages as you can move the plywood closer to the plants when they are young to create more effective light reflection and then move the plywood back against the wall as the plants grow larger. This works best for larger grow rooms where there is enough space to get around the plants and move the reflective sheet boards around.
Things to consider
It is best to go around the whole room in one roll so that the corners are rounded rather than doing the walls separately and leaving the corners at 90-degree angles. As mentioned before, if you can not keep the mylar material flush against the wall without folds and creases then you will gain better reflection from matt white paint – which also gives no damage to clean up unlike using adhesive or battens for hanging mylar.
It is very important to ensure the mylar does not fall down as it could start a fire if it falls onto a HPS light bulb or ballast!