How to choose greenhouse plastic?
Not just any type of sheet plastic will do when you’re constructing a greenhouse. There are a couple of things to consider when choosing plastic for your greenhouse, the most important of which we’ve listed down below.
1. Durability
The material of your greenhouse will be subjected to quite a lot of extreme conditions. It may need to endure torrential rains, strong winds, or heavy snowfall. Even direct sunlight isn’t exactly favorable to all plastics since a lot of them can turn brittle with constant UV exposure. A single tear on your greenhouse plastic can drastically reduce its effectiveness, so investing in a high-quality plastic sheet made with the appropriate material will save you from a lot of future headaches.
2. Transparency
Greenhouses that are literally colored green are no longer common nowadays. In fact, the use of green-colored materials for a greenhouse is pretty much an outdated practice. In modern times, most growers have gotten the best results with materials that are as transparent as possible.
Take note that one of the objectives of a greenhouse is to allow sunlight to reach the plants so they can go through photosynthesis. This means that you would want as much sunlight as possible to go through your greenhouse walls. Transparency typically isn’t much of an issue when using clear fiberglass or glass panels but finding the right balance between transparency and thickness can be tricky if you’re using plastic sheets.
3. Weight
Although thick plastic sheets are stronger, they are also heavier. A plastic sheet provides no structural integrity whatsoever. This means that all of the weight of the plastic sheet will fall onto the frame of the greenhouse. While a heavy plastic sheet isn’t necessarily bad, just make sure that your greenhouse was built with the weight of the plastic sheet in mind.
4. Anti-drip and anti-dust properties
Depending on outdoor conditions, there could be several factors that could reduce the effectivity of your greenhouse. On cold days, the imbalance between the cold outer surface and the warm interior of a greenhouse could result in condensation forming on the inner surface of your plastic sheet. These condensate droplets could end up falling on your plants, disturbing the delicate ecosystem that you’ve so carefully crafted by promoting the growth of mildew.
Some plastics are naturally equipped to prevent this from happening. Plastic with a hydrophilic radical, such as -COOH (or carboxylic acid) helps prevent condensates from dropping onto the plants, instead retaining them on the surface to evaporate naturally. On the other hand, you would want to avoid plastics with hydrophobic radicals such as -CH groups, since they will repel condensate droplets.
Dust buildup can be an even bigger problem for a greenhouse, as it can drastically reduce the transparency of your plastic sheet. Some plastics naturally retain excess charge on their surface, which will make it so much easier for dust to accumulate on your greenhouse panels.
