📌 Quick Summary: The Mylar Greenhouse Hack
- 🌑 The Shade Problem: If your greenhouse is built too close to a fence, house, or tree line, the shaded side will stay cold, and the plants will become leggy trying to reach for the sun.
- 🪞 The Mylar Solution: Hang highly reflective Mylar film (commonly used in indoor grow tents) on the inside of the dark, shaded wall (usually the North or North-West side).
- ☀️ Free Heat & Light: The Mylar acts like a giant mirror, bouncing sunlight back onto the plants. This “sunbeam effect” drastically increases light levels for photosynthesis and warms the soil on the dark side of the greenhouse much faster in the spring!
Ketrin007 (Ekaterina) wrote:
By the way, what is that shiny stuff on the wall in your picture? Is that foil?
Katya, good morning!
It’s freezing here too. That shiny stuff on one side of my greenhouse is a highly reflective film meant for indoor grow tents.
My greenhouse is pushed right up against my neighbor’s fence and his outbuildings, so that entire side is completely shaded (it’s the North-West wall). I hung the film there, and it reflects the sun and ambient light straight back onto the plants. It creates a massive “sunbeam” mirror effect!
Because of all that reflected light, my automatic roof vents started opening much earlier on sunny days, and the soil in that shaded bed finally warmed up—which is exactly why I was able to plant early!
👨🔬 Editor’s Botanical Note: The Mylar Greenhouse Hack
Galina’s trick with the reflective wall is a phenomenal hack for gardeners dealing with small, shaded suburban lots!
If part of your greenhouse is shaded by a fence or a house, the soil on that side will stay much colder in the spring, and your tomatoes will grow leggy and lean toward the sun. By hanging Mylar film (the highly reflective silver material used in hydroponic grow tents and emergency space blankets) along the solid North or North-West wall, you bounce the sunlight coming from the South directly back onto the plants.
Unlike regular aluminum foil (which easily tears and creates “hot spots” that can burn leaves), Mylar diffuses the light evenly. This essentially gives your plants sunlight from two directions at once, boosting photosynthesis and rapidly heating the soil on the shaded side of the greenhouse!
