Here's What Industry Insiders Say About Greenhouse Covers

Uses for Greenhouses

Before building your greenhouse, you will need to ask yourself a few questions. How will the greenhouse be utilized?  How big will it be?  Where will it be located?

Placement and materials are also things you need to consider.  If you want your greenhouse to last a while, you might consider a custom cover made from good material.  You can purchase frames and you can have a cover customized to your dimensions.  Custom covers are affordable and can last for many years. What you grow will determine the amount of light transmission needed.  The amount of light transmission you need will determine the type of material you should use. The size of your greenhouse will be determined by your growing goals.

For placement/location of the greenhouse, keep in mind that what might work in Texas may be different in Kansas.  Both will be different in Vermont.  One might think Texas would be the last place to need a greenhouse cover for vegetation, but surprisingly due to the weather extremes, a greenhouse is often needed.  A straight line through Texas North to South is 801 miles.  East Texas to West Texas is 773 miles.  The winter weather in Amarillo versus San Padre would be vastly different.  The same applies to Houston versus El Paso.   Location differences and differences in weather conditions relate to not only the placement of the greenhouse but the type of material and light transmission to consider. 

It’s best to have 80% light transmission (depending on what you are growing), but if the sun is extreme in your area you may have to consider having a shade cloth on hand.  The light transmission needed would be less for certain tender plants. If you are just using the greenhouse cover for plant protection then you could get by with 0% light transmission or diffused light.

Greenhouse Systems 

• Wiggle Wire (WW) is the most common fastener on the market for securing a greenhouse cover. It is a steel wire that is used in combination with an aluminum channel to secure the material in place. 
• The Poly Lock system also utilizes an aluminum channel with a second piece that snaps over your cover which is sandwiched in between the two aluminum strips. This system allows you to easily remove the cover and vent your greenhouse if needed.

There are pros and cons for both systems. A wiggle wire system would likely trap debris between the wire and cover whereas the poly lock system closes up over your greenhouse fabric and is relatively easy to snap into place securing the greenhouse material.  The poly lock system may cost a little more.

Problems with Greenhouses

Sometimes excess water droplets can build up on the inside walls of the greenhouse. This would affect your light transmission.  If the excess condensation remains on your plant leaves, it can cause problems like mold or plant disease. You might consider spraying your greenhouse material with an anti-condensation coating (be careful not to get it on your plants and don’t overdo it).  

There are a few things you can do to prevent excess condensation on your plants. You want to keep the air circulating inside your greenhouse.  If you heat the greenhouse, you can run a ventilation fan in the evening, but try to keep an even temperature. If weather permits you can vent your greenhouse in the daytime to even out the temperature allowing some of the condensation to dissipate.

Protect Your Investments 

The ideal greenhouse covers are manufactured using a UV stabilizing additive to protect them from UV degradation and help them retain their original properties. High-strength reinforced construction helps to protect against tears often associated with installation. You will need a good system to attach your cover to the greenhouse frame. Your ideal cover should work well with the poly lock system and the wiggle wire system.  It’s possible to manufacture your own system to lock the cover in place, but be careful with your investment.  If the material is not secure, the weather could wreak havoc on your cover. A heavy-duty greenhouse cover is ideal for protecting investments from the unwanted light transmission and provides long-term service in high UV level environments.

A clear, reinforced polyethylene laminate containing 60% more UV stabilizer additive than its predecessor makes it a favorable choice in environments with above-average UV levels. Covers can be available in stock configurations or can be custom fabricated to meet your exact requirements. Greenhouse Covers can be available in various colors and material grades depending on your protection needs.   

The light diffusion material you use could really make a difference in greenhouse covers.   If you are not familiar with the term diffused light, think of a lamp with and without a lampshade.  Without a cover, the light would probably shine directly on your face. You put the shade over the bulb and the light appears to spread over the room.  A light diffusion fabric would cause the UV rays to be scattered.  The effect is a better light distribution for equal growth of agricultural goods. Instead of your products maturing faster on top because of the direct sunlight, the growth would mature more evenly.

There is a wealth of knowledge out there that can help with finding the right greenhouse cover for you. Whatever you decide, happy growing!

High-quality plastic greenhouse coverings can help protect your investments for years. Griffolyn® polyethylene reinforced greenhouse covers will help you do just that. Griffolyn® greenhouse coverings have been performance engineered to be highly resistant to tears and punctures with an exceptional ability to retain strength and flexibility in the most extreme environments. Due to their long-life expectancy, Griffolyn® materials provide significant long-term cost savings offering unmatched life expectancy in almost any environment.