Connecting the blower to use outside air will reduce condensation between the two layers. Plastic failure Early failure of polyethylene film can be attributed to attachment stress, abrasion on rough surfaces and sharp edges or heat build-up in the area of rafters, purlins and extrusions. Contact with chemicals from pesticides or pressure treated lumber can also affect the life of the plastic. Polyethylene may also be subject to cuts from blowing ice especially if there are multiple greenhouses adjacent to each other.
A scrim reinforced poly may be desirable in these situations. John Bartok Jr. Water issues were a major focus of the conference, including water quality related to pathogens that reside in water and the impact a water source can have on pH and nutritional management. Growers in areas of the country that recently experienced drought conditions and restricted water use know firsthand how important a reliable source of water is to the survival of their business.
Growers in the Southeast have been especially hard hit the last few years suffering through severe drought conditions. During nearly 50 percent of the country was experiencing some type of drought.
The changing landscape The issue of water availability is expected to become an even bigger issue as the federal courts put increasing pressure on the federal EPA to begin stricter enforcement of the Clean Water Act. The result is EPA has proposed more stringent regulation of nutrient water quality standards for Florida. EPA is also looking to begin to enforce limits on storm water pollution that will have a major impact on how cities deal with runoff.
USA Today reports these more stringent limits could force cities to make major changes in road construction and residential and commercial development including landscaping.
The paper said local governments, which are facing mounting budget deficits, are putting more of the financial burden of maintaining storm water systems on residents and businesses. One city that has taken a proactive sustainable approach to storm water management is Portland, Ore. Its Green Streets and Ecoroof programs are aimed at reducing storm water runoff. The city has about 50, homeowners who are directing runoff from rooftops into gardens and rain barrels.
The city is also offering financial incentives to property owners and developers to install ecoroofs. The city has of these roofs that cover 24 acres. Expect our industry to receive more pressure to reduce runoff with a great opportunity for our product to be part of the solution. The Alcea rosea annua Spring Celebrities series from American Takii is a multi-use plant that can be grown as a cut flower, used in large containers or planted in the landscape. Three new colors are being introduced this year: Crimson, Lilac and Pink.
Plants are quite cold tolerant, though flowers will be damaged by frost. In the garden plants take full sun, are drought tolerant and attract butterflies. Seed should be sown from March through June in large plug cells cell tray or larger filled with a well-drained growing medium with a pH of 5. Cover the seed with vermiculite. Keep the growing medium evenly moist through germination. Germination occurs in eight to 10 days. Supply plugs with 75 parts per million nitrogen flushing the growing medium with clear water occasionally to prevent salts build up.
Plugs should be ready to transplant into finished containers in five weeks. Plugs should be planted before tap roots form. Plant one plug into a 1-gallon container filled with a well-draining growing medium with a pH of 5. Keep the medium pH level below 6. Maintain a moderate moisture level and do not allow the medium to dry out.
Excessive drying can result in the yellowing and loss of lower leaves. Alceas are heavy feeders. Apply calcium and potassium nitrate at ppm constant feed.
Low fertilizer levels can result in the yellowing of lower leaves. Like other polyethylene sheeting, make sure to prime a PVC frame before use.
The Clear Heavy Duty polyethylene greenhouse plastic from Arc Direct is a beefy 14 mils thick, thanks to embedded polyester mesh that makes this product more of a tarp than just plastic sheeting. The finished tarp size is just over 9 by 19 feet, and the edges are folded over and finished with reinforced rope for extra durability. The tarp also features UV blockers and is rot- and acid-resistant. It comes with reinforced aluminum grommets spaced every 18 inches along the edges to stake the tarp to the ground for additional wind resistance.
This multipurpose cloth features percent UV-stabilized polyethylene and can be installed over a standard hoop greenhouse frame. It features reinforced grommets along the edges for staking or tying down the cover and serves as an essential wind and sun break when used on a greenhouse. The shade provided by this polyethylene film makes it suitable for regions that experience a lot of hot sun.
The plastic is reinforced with a polyester cross-weave mesh that gives the clear plastic added strength and durability. In addition, the tarp features UV blockers and reinforced grommets every 36 inches along its rope-hem edges. It measures 12 by 24 feet and is both waterproof and rot resistant. Especially due to the double-reinforced corners, this greenhouse tarp offers strong protection against the elements, making it ideal for regions subject to high winds or storms.
Cover a sizable high tunnel or hoop house with the Farm Plastic Supply Clear Greenhouse Film that measures 24 by 50 feet other sizes may be available.
At 6 mils thick, this simple polyethylene film is well suited as a greenhouse cover, and it includes UV blockers to protect plants from scorching sun rays. The film is suitable for use on a wood- or metal-framed greenhouse structure. It can be installed in a double layer on a smaller structure if desired to increase thickness and wind protection.
The film is 6 mils thick and designed to resist tears from high winds and storms. It includes UV blockers but still offers a maximum amount of light transmission, making this film well suited for placement in a spot that provides at least some protection from the hot afternoon sun. Install on a wood- or metal-framed greenhouse for the best results. Growers wanting to produce healthy vegetables or grow flowers in a greenhouse will likely have some questions about the types of greenhouse plastic available.
Clear plastic lets in more direct sunlight than white greenhouse plastic. Most plastics are somewhere between crystal clear and white, with many featuring just a touch of opaqueness. For the easiest installation, drape plastic film over the greenhouse frame and attach it with furring strips.
Rigid plastic panels are typically screwed directly into the greenhouse frame. Our choices are based on material life-span, price, availability, and technical specifications. If you want to see our reasoning in MUCH more detail keep reading through the rest of this post, but if you are in a hurry, here are the best available greenhouse plastics for most growing applications:.
The 6 mil plastics are often cut-to-order, but there are often a variety of Pre-Cut 6 mil sizes available. The above are recommended greenhouse plastics based on each option having a TON of value for the cost, as well as for how long each option can last before needing replaced. They are also recommended based on our direct experience. We've handled all of these plastic films, and know for a certainty they will work well as suggested. While we feel the plastics recommended above are fantastic, there are other great options outlined through the rest of this post that might be more ideal for some operations.
Let's compare greenhouse plastics in more detail below. The recommendations for greenhouse plastic we make are based on more than a decade of installing and handling hundreds of covers on a variety of greenhouses, high tunnels, and hoop houses. In order to outline the best greenhouse plastic for your needs it is first necessary to learn how to compare greenhouse plastics.
While a variety of manufacturers make Greenhouse Plastic, their products typically fall within a few common categories. These categories can be used to help narrow down which plastics are best for you:.
The greenhouse plastics we recommended at the beginning of this post weighed all of the above categories against each other, but if you care more about one of the listed categories than the other, it is certainly possible to make a greenhouse plastic selection based solely on one or the other. Whether you use one category to make a decision, or you weigh all of your options, looking into the different ways to compare the plastic films is a great way to begin narrowing things down.
Below we go through the three main ways to compare greenhouse plastic , and while we come to our own conclusions for the best greenhouse plastic above, you may find that a different type of covering meets your needs better. Greenhouse films have slightly different technical specifications. The technical specs most often used for making comparisons are outlined below:. Light Transmission: How much light can pass through the plastic and onto plants. Diffused Light Percentage: The spread of light that passes through the plastic.
Anti Drip Properties: Can the plastic reduce the amount of internal dripping on plants. While other technical specs are available for most greenhouse plastics it becomes more and more difficult to compare those specifications across all plastics. Source: individual specification sheets from various manufacturers and suppliers.
The above list of covers is not exhaustive; there are countless cover options available for every type of grower. The above list does provide a comparison of the most widely used plastic coverings on the market though.
While light transmission, diffusesd light, and anti drip are the most commonly compared technical specs of greenhouse plastic they are not the only ones worth knowing. For those installing heaters, or maximum heat retention it is also important to look into the plastic coverings R-value. Essentially, a value is given to coverings in order to show how well it resists the flow of heat. For all objects with an R-value, the higher the value the better its ability to resist heat transfer.
In the world of greenhouse plastics most pliable plastics have negligible values associated with them. There are however some greenhouse plastics that do have notable R-values:. The last example listed above is a HUGE deal. The reason Double layer inflated greenhouse plastic systems take two layers of economy plastic, and add an inflation blower fan in order to create better insulation and a higher R-Value In other words, light transmission stats and cost are thrown to the side, and most attention is paid to which plastic can hold up to wind, rain, hail, and years of sunlight.
All of the coverings we've discussed in this post so far do a great job in inclement weather, but there are a few notable winners when it comes to being able to withstand a beating. Below I note the comparable durability of each major greenhouse plastic covering.
This greenhouse plastic is the most popular for a reason. Of the durable plastics covered here it is the least costly. In other words, this plastic can move a ton in the wind, and can hold a ton of weight without breaking or busting. It is, however, much easier to puncture than any of the other plastics detailed in this section. Something to keep in mind if you live in an area where wind could blow branches or sticks toward your structure.
Woven greenhouse plastics are, for the most part, stronger than 6 mil greenhouse plastics. They aren't as stretchable, and for this reason it is more difficult to pull all of the tension out of these plastic coverings. For this reason, these covers might move more in the wind over their extended life if not installed well. With this being said, they are very difficult to puncture and can hold a lot of weight.
Many woven greenhouse films can hold many multiples more than 6 mil greenhouse plastic. SolaWrap is a unique covering option because it comes in very long rolls that are very narrow. This means it must be installed in a completely different ways than pretty much every other covering option on the market. Ultimately, the SolaWrap covering is installed and attached to every single bow of a structure.
This compounds how durable and strong the SolaWrap covering is, because the plastic connects directly to the frame of your structure every 4 ft. Because a permanent attachment is made every 4 ft. This, when combined with its thickness and durable outer coating make SolaWrap the most durable all-purpose greenhouse plastic on the market. It is nearly impossible to break the stuff in half too. Take it from me, I have tried.
While 8 mm Twin Wall Polycarbonate sheeting is stronger than standard plastic coverings it is a hard glazing so it can, unfortunately, dent.
Because it can dent in some scenarios, twin wall polycarbonate is often the covering of choice for end-walls, but not installed on the tops of structures. This is where many customers usually start their search for greenhouse plastic. Which greenhouse plastic will last the longest? Whether a grower or builder, it makes a lot of sense to compare greenhouse plastics by the number of useful years you'll get out of it.
Trying to source a greenhouse plastic with the longest possible lifespan does indeed make a lot of sense. We go into much more detail below, but the chart here can be used to compare the lifespans of different greenhouse covers.
Most often there is a trade off between expected lifespan and the price of greenhouse plastic. Plant nurseries, for example, will often use what is referred to as overwintering plastic. This type of plastic is VERY inexpensive compared to other types of greenhouse plastic.
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