Are Plastic Greenhouses Really the Best Option? The Hidden Challenges You Need to Know

Plastic greenhouses have become a popular choice for gardeners and farmers, thanks to their low cost and ease of installation. They offer an affordable way to extend the growing season and protect plants from harsh weather conditions. However, while plastic greenhouses seem like a great solution, they come with several challenges that many people may overlook. Here’s a closer look at the issues you should consider before investing in a plastic greenhouse.

Cost: Is It Really as Cheap as You Think?

Plastic greenhouses are often seen as an affordable alternative to glass or polycarbonate (PC) greenhouses. Smaller plastic models are typically priced lower, which makes them appealing to hobbyists and small-scale gardeners. However, the cost of plastic greenhouses can vary significantly depending on the type of plastic used and its durability. If you want a longer-lasting greenhouse, you’ll need to invest in thicker, UV-resistant plastics, which can increase the cost substantially. Additionally, as the size and complexity of the greenhouse grow, so does the price, reducing the initial cost advantage.

Heat Retention: Can They Really "Cook" Your Plants in Summer?

Plastic greenhouses are excellent at retaining heat, which is great for colder climates, but they can cause problems in hot weather. In areas with intense summer heat, temperatures inside a plastic greenhouse can easily exceed 90°F (32°C), which can damage sensitive crops. In these conditions, plants like lettuce and spinach can wilt, stop growing, or even die. To counter this, additional cooling measures such as ventilation systems or shading are necessary, adding to both the cost and complexity of managing the greenhouse.

Light Transmission: Will Your Plants Get Enough Sunlight?

While plastic allows light to enter the greenhouse, it doesn’t maintain consistent light transmission over time. UV rays from the sun cause the plastic to degrade, yellow, and lose its transparency. A plastic cover that initially lets in 80% of light may drop to 50% or less after just a few years. This reduction in light intensity impacts photosynthesis, which in turn slows plant growth and reduces yield and quality. Glass greenhouses, especially those with high-quality diffusing glass, maintain more stable and consistent light transmission for a longer period.

Durability: Will It Last Long Enough?

Plastic greenhouses tend to have a shorter lifespan compared to glass or metal alternatives. Even UV-resistant plastics usually only last around 3-4 years before they start degrading. Regular plastic materials degrade much faster. Additionally, thin plastic coverings are prone to tearing, especially in areas with strong winds or hail. For example, in regions where winds are frequent, plastic greenhouses often require frequent repairs or even complete replacements. Even with thicker plastic, the material can crack due to the expansion and contraction from temperature changes, further reducing its lifespan. By comparison, glass greenhouses can last 40-50 years with minimal degradation, offering better long-term durability.