I have a balcony garden where I get a ton of sunlight on my wall, but not much on my plants beneath this wall. I planned on using a reflective panel made from cardboard and aluminum foil to reflect some light down.

Will be effective? Will it be safe? I don't want to start a fire on my balcony!

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    Just keep the aluminum straight, no focal point, and you should be OK. Avoid this: London skyscraper's 'deathray' reflection is melting cars, burning businesses, but also cooking eggs nationalpost.com/news/… Apr 14, 2018 at 16:26
  • Thanks, yeah I don't plan on doing that! I actually have three panels, so I want to keep them straight not reflecting all on one spot?
    – MR_Q
    Apr 14, 2018 at 16:52
  • What are you wanting to grow MR Q? Food crops flowering perennials/shrubs? Grow plants that love partial shade. Using foil is plain insanity. Are you trying to grow vegetables? Foil and focusing light should NOT be necessary...Plants that love partial shade are an incredible humongous group! You are reflecting HEAT more than a full spectrum of light wave lengths.
    – stormy
    Apr 15, 2018 at 6:12

1 Answer 1


Aluminum foil can be very effective at reflecting light. There are better materials out there, like reflective mylar that are easier to work with. There is also a product called Reflectix which is a mylar bubble wrap used for insulation and it won't tear of bend like aluminum. Even just painting something white can work really good. I think the reflectivity of aluminum and mylar is around 95% while white paint is around 75% depending on the paint. Of course, cannabis growers debate this endlessly. Here is a good video testing the different materials.

  • Thanks for the video Steve! I might upgrade, this is just a test right now. Are there fire concerns for any of those?
    – MR_Q
    Apr 14, 2018 at 16:53
  • And there are inexpensive mirrors , about 1 ft. X 4 ft. These have an advantage that they can be handled easily compared to foil. Apr 15, 2018 at 19:32

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