Keeping Cool With Greenhouse Shading

Greenhouse–shade compound, whitewash

Shade is used to reduce the temperature and light inside a greenhouse. The radiant energy from the sun can easily build up inside of a greenhouse during the summer and increase temperatures beyond the desired range for many crops. Additionally, light levels in the summer regularly exceed the usable level by plants, and excess light may result in high-light damage. However, the use of shade cloth can often reduce the air temperature by up to 10°F (5°C) and light levels by up to 75 percent or greater, depending on the shade material used.

Two Ways To Provide Shade In A Greenhouse


There are two primary options for providing shade: shading compound or whitewash; or shade curtains or shade cloth. Each of these options has distinct advantages and disadvantages, which warrant consideration when deciding how to reduce light and temperature in the greenhouse.

Shade compound, or white wash, is a paint-like substance applied to greenhouse covering. The magnitude of shading for shade compound is dependent on how much the original material is diluted — higher dilution of shade compound results in less shade, whereas a higher concentration of compound increases shading. 

For best results with shade compound, apply to dry greenhouse glazing materials outside the greenhouse in the morning or in the late afternoon with a brush, roller or sprayer. Be sure to keep an eye on the weather, as rainfall within 12 to 24 hours after application may wash off the newly applied shade compound. Once the shade compound has been applied, it will consistently provide shading until it is removed by washing in the fall. This means that during periods of low light in the summer such as early morning, later evening, overcast days, etc., incoming light will be further reduced and result in suboptimal light levels.

The costs associated with using shade compound are primarily the labor to apply and remove the shading compound, as the actual material is not very expensive, though the labor costs will be incurred each year shade is applied.

Shade curtains are the other primary choice for reducing heat and light inside a greenhouse. Several factors must be considered when designing a shade curtain system for greenhouses, including shade placement, shade curtain materials, and system configuration.

The first decision to be made is whether to place shade curtains on the exterior or interior of the greenhouse. Shade curtains are placed on the outside of a greenhouse are more effective at reducing temperatures inside a greenhouse because radiant energy from the sun is absorbed or reflected by the curtain outside, before it enters the greenhouse. However, the functional life of shade curtain placed outdoors is reduced due to exposure to the elements like snow. Outdoor shade is usually used in warm, southern climates such as Florida.

Next, you need to select the appropriate type of material for the curtains. Most popular shade curtains are made with aluminized polyester. The percentage of shading is determined by the width of the aluminized strips and the space between strips. Aluminized curtains reflect light and, therefore, minimal energy is absorbed by the curtain, maximizing the cooling benefits of shade. In addition to shading, curtains may be designed to diffuse light, brightening shaded areas and moderating bright spots. Additionally, one of the biggest benefits of shade curtains is that they can also double as an energy curtain when drawn at night to minimize the radiant heat loss and/or the volume of air to be heated.

One of the main advantages of shade curtains is that they can be dynamic, opening and closing based on environmental conditions, minimizing suboptimal light levels as a result of unnecessary shading. You will need to decide which type of curtain configuration will work best for you. Shade curtains are either drawn from gutter-to-gutter or from truss-to-truss. Gutter-to-gutter curtains run the length of a greenhouse and, as the name implies, are drawn from one gutter to another. One disadvantage of this system is that it may be difficult to accommodate superstructure like supplemental lights, electrical conduit and ventilation tubes.

Configurations Of Truss-To-Truss Curtains: There are three types of configurations used for truss-to-truss curtain systems: flat-at-gutter-height, slope-flat-slope, and slope-slope. Flat-at-gutter-height systems draw shade curtains from truss to truss at the height of the gutter. Functionally, the flat-at-gutter-height is similar to the gutter-to-gutter, with similar advantages and disadvantages. The slope-flat-slope design has the shade curtains running parallel with the roof up until a certain height, when the curtain then runs flat for a certain length before sloping with the opposite roof. Slope-flat-slope designs allow for superstructure to be suspended under the shade curtain. Lastly, the slope-slope design is where the shade curtain runs parallel to the roof. These different shade curtain configurations will also affect the balance of warm and cool air masses. Gutter-to-gutter and slope-flat-slope configurations will hold warm air during the day when curtains are used for shading due to the air mass above the curtain; however, when used at night as an energy curtain, these configurations also minimize the air space requiring heating. Alternatively, the slope-to-slope design will minimize warm air above curtains during the day. When used as energy curtains in this configuration, heat loss at night will still be reduced, but the air space to be heated will not be reduced by much.

Using shade to reduce temperatures and light during the summer can improve crop quality and worker comfort inside the greenhouse. However, you will need to evaluate what your goals are and what type of investment you are going to make. Whether it is simply applying shade compound or installing shade curtains, the benefits of using cloth will usually outweigh any investment costs in a short period.






Leave a Reply

More From Equipment...
Smith Gardens Marysville outdoor field production

November 30, 2015

Why Smith Gardens’ Marysville, WA, Facility Is A Great Place To Work

Labor rates in Washington State are some of the highest in the nation, making competition for labor fierce. This is why Smith Gardens in Marysville, WA, wants to strengthen its reputation as a great place to work.

Read More
Feature - Agave ‘Blue Waves’ (Rancho Tissue Technologies)

November 30, 2015

Spice Up The Garden With 12 New Succulent And Miniature Plant Varieties

New succulents and miniature plants for 2016 offer a variety of colors and foliage textures that add interest and visual appeal to any size garden — indoors or out.

Read More
Iridescent green sweat bee

November 30, 2015

Nine Native Bees You Should Know About

There are at least 17,000 other species of bees globally, and 4,000 native bee species in North America. Although honeybees get all the attention, native bees can be efficient and sometimes superior pollinators compared to honeybees. Here's a quick run down on what you should know about native pollinators.

Read More
Latest Stories
Feature Image Cob 700 (NewLux)

November 28, 2015

16 LED Lighting Solutions For Your Greenhouse

Narrowing in on the right LED lighting product often comes down to considering your specific crop needs and growing requirements to see what works best for your application. Here are 15 LED products to take into account when choosing the right fit for your greenhouse.

Read More

October 27, 2015

How Dallas Johnson Greenhouses Is Simplifying Shipping

Two years ago, Dallas Johnson Greenhouses, a 61-acre operation in Council Bluffs, Iowa, and No. 21 of Greenhouse Grower’s Top 100 Growers, was struggling to get its orders out. With its range of potted annuals, there were so many skus that it was impossible to get enough carts into the shipping greenhouse, and the crew couldn’t get orders processed fast enough. As a result, the operation was consistently pulling orders until midnight every night during the busy shipping season, says President and CEO Todd Johnson. So Johnson got together with Arie Van Wingerden at Cherry Creek Systems to discuss his problem, and what they came up with has changed everything, Johnson says. Inside one of Dallas Johnson Greenhouses’ existing structures, the team installed a shipping system made with Echo-Veyors, the popular cable conveyor system designed by Cherry Creek Systems. The system was placed right in the front of the greenhouse, […]

Read More
Tidal Creek Growers

October 24, 2015

Five Tips For Successful Use Of Boom Irrigation Lightin…

Michigan State University Extension shares five tips to help growers use boom irrigation lighting more effectively to accelerate flowering of long-day ornamental crops.

Read More

October 8, 2015

Industry Standards For Greenhouse Lighting On The Horiz…

As the use of LEDs has risen among greenhouse growers, so have concerns about the best way to measure and compare the many LED light products across the market. As a result, the lighting industry is responding to a call for greater transparency and the development of standardized measuring and testing methods.

Read More

September 28, 2015

11 Products For Precision Greenhouse Growing

These new options in equipment, automation, structures, lighting and software are designed to help growers run their operations with efficiency and accuracy and at a lower cost.

Read More
Laura Drotleff

September 25, 2015

Growers Solve Problems With Precision Horticulture

My dad’s hands are covered with sores, nicks, scratches and bruises. It’s the ongoing reward — or drawback — of his ingenuity, as he’s constantly wrenching on equipment or constructing new innovations that will help him get work done more efficiently on the farm. As a kid, I would always marvel at his toughness, and how he would barely notice a new wound, shrugging it off as he kept working, driven to complete his work and bring his idea to fruition. He’s still at it today, and his hands tell the story of the many projects he’s completed over the years. I’m guessing many of you can relate, and your hands look similar to my dad’s. After all, ingenuity is the name of the game in this business, where creative thinking to solve problems often leads to revolutionary solutions that automate production, save labor and cut costs. That’s easy to […]

Read More

September 24, 2015

AgriNomix Helps Keepsake Plants Cut Labor Costs With Au…

Keepsake Plants reduced labor for trimming Hydrangeas from 60 people to 28 by automating the process with AgriNomix Venti Trimmers.

Read More

September 24, 2015

4 Dramm Products That Put The Precision Into Growing

When accuracy counts, the right tool makes all the difference. New products from Dramm put tools in growers hands to get the job done efficiently.

Read More
The single cells move forward, still grouped with their pack, until the pack is positioned in front of an arm that can pick up several individual plants at a time

September 24, 2015

How Spring Meadow Nursery’s Custom Sorting Machine Kee…

The Michigan-based nursery uses automation to cut apart trays of immature plants and regroups them into new trays of similar-sized plants.

Read More
Figure 3. Sole-source lighting in a multi-layer vertical growing system utilizing hydroponics for vegetable production.

September 23, 2015

MSU Offers New Greenhouse Lighting Online Course For Gr…

  Michigan State University Extension is now offering a non-credit, pre-recorded online course on greenhouse and horticultural lighting. The lighting course is intended for greenhouse and ornamental plant growers and others interested learning about the fundamental concepts about how plants respond to light quality, quantity and in duration. It provides introductory to moderately-challenging content primarily based on experiments performed at Michigan State and Purdue Universities. This is the second course in the College of Knowledge Online series offered on the national Extension website. The first course was Floriculture Root Zone Management, also available online. What Growers Will Learn From Taking This Course The 3-hours of pre-recorded lecture and video demonstrations are divided into seven units. The first and second units cover the properties of light and its importance for plant growth and development. The third unit discusses how light quality influences stem extension and flowering. The fourth unit of the course teaches […]

Read More
ArmstrongGrowers Hanging Basket Area

September 22, 2015

Sole-Source Lighting In Horticulture: Bedding Plant Plu…

Researchers determine how sole-source LED lighting can be used effectively for the production of bedding plant seedlings.

Read More

September 18, 2015

Visser North America To Provide Mayer Potting Machines …

Visser North America (NA) will now be the official North American supplier for sales, service and parts provider of Mayer potting machines and equipment. The Mayer premium line of potting machines is the latest addition to the Visser NA lineup, including the NewLux, Logitec Plus and Visser product lines. “Much like our current product lines, Mayer is a leading provider of potting machines and further horticultural equipment worldwide and its brand represents quality in our industry,” says Kevin Vander Ploeg, president of Visser NA. “We believe in providing our customers with the best solution for their operation with ongoing support and service excellence. Naturally, we are pleased to add Mayer to our product line up.” Mayer, a German company manufacturing in Europe and with a global presence, has been designing and manufacturing potting machines since 1967. The Mayer product range includes solutions for the entire process chain from soil preparation to filling of pots/trays […]

Read More
Costa Farms’ new solar panels will offset 493,487 pounds of carbon dioxide annually

September 15, 2015

Costa Farms Ramps Up Sustainability Efforts With Solar …

Costa Farms is seeking to make sustainability a top priority at its headquarters and two other buildings in Miami with the recent construction of new solar panels, which will replace 25 percent of the company's power usage with solar energy.

Read More
Trays move on an overhead conveyor to the end of the production line, where workers carefully pack the cleaned, sized, graded, counted and sorted Calla tubers

September 14, 2015

Golden State Bulb Growers Increases Efficiency With New…

Necessity is the mother of invention, and that’s certainly true for Golden State Bulb Growers. The Moss Landing, Calif., operation, which supplies its Callafornia Calla Lily bulbs to wholesale markets around the world, was in need of a more streamlined and less labor-intensive solution to grade and sort bulbs. So Golden State’s management team got creative and started talking with MAF Industries, part of the MAF-RODA Group that specializes in the design and manufacture of grading, packing, palletizing and handling fresh fruit and vegetable systems. The manufacturer was willing to work with Golden State on the Calla Lily bulb grading and sorting machine design process. This resulted in Golden State Bulb Growers investing $700,000 to purchase the new grading system to better serve the needs of its customers, increasing uniformity and productivity in its Callafornia Callas bulb processing. Investing in the new system has also allowed Golden State Bulb Growers […]

Read More
Figure 1. Mustard microgreens grown under sole-source (SS) lighting using light-emitting diode (LED) arrays.

August 21, 2015

Sole-Source LED Lighting In Horticulture: Microgreens P…

In Part 3 of a four-part lighting series highlighting the multiple uses of light-emitting diodes (LEDs), researchers examine the effects of sole-source LED lighting on microgreen production to achieve the highest quality crop possible in an energy efficient manner.

Read More
Lighting 2015 August Feature Image

August 14, 2015

Customizing Crop Foliage Color With LEDs: Ornamental Cr…

Do you find that your purple fountain grass (Pennisetum setaceum ‘Rubrum’) crop is often green to light purple? What if we told you there is a quick solution to enhance and darken the foliage of purple fountain grass or other floriculture crops? In this second article of a four-part series highlighting the multiple uses of high-intensity light-emitting diodes (LEDs), we will discuss our research methodology and findings for enhancing the foliage color of ornamental crops with end-of-production (EOP) supplemental lighting (SL) in the greenhouse. Many ornamental crops that greenhouse and nursery growers produce vary in size, shape and color. These variables are often influenced by the growing environment. For example, leaf color (intensity, distribution or both) of ornamental crops such as purple fountain grass is a key component that often influences the consumer’s perception and ultimately an impulse purchase. The red or purple pigmentation of purple fountain grass leaves is […]

Read More
WaterPulse retail mats can help cut water use in retail settings

August 10, 2015

Technology Provides Solutions For Growing In Drought

In April, California Gov. Jerry Brown directed the State Water Resources Control Board to institute reductions in cities and towns across the state with the goal of reducing water usage by 25 percent. The announcement comes following the lowest snowpack ever recorded in the High Sierra. It was the first time in state history that action was taken to implement mandatory water restrictions. In May, the farmers in California’s Sacramento-San Joaquin River Delta agreed to reduce their water use by 25 percent in exchange for assurance that they will not face further curtailment during the June to September growing season. Their proposal was approved by the State Water Resources Control Board. Growers who participate in the program could opt to either reduce water diversions under their riparian rights by 25 percent, or fallow 25 percent of their land. Given these conditions, growers and retailers are in need of methods and […]

Read More
Heating Roundup Feature Image

August 1, 2015

5 New Heating Options For The Greenhouse

Five heating systems manufacturers share their latest and greatest products. Tubing And Aluminum Heat Pipes (BioTherm) From Megatube and MicroClimate tubing to DuoFin and StarFin aluminum heat pipe, BioTherm is dedicated to providing heat solutions that can withstand the toughest greenhouse environments. The MegaTube and MicroClimate tubing options are easy to install and ideal for bench or floor heating. The tubing has a conductive heating surface that allows for maximum root-zone heating. The DuoFin and StarFin aluminum pipe options are great for perimeter heating and melting snow trapped in the greenhouse gutter. It can also be useful for bench heating. Both pipe options provide gentle, radiant heat for plants and don’t require welding. Infinite Energy 2 Condensing Boiler (Delta T Solutions) With up to 98 percent efficiency, the IE2 condensing boiler boasts a stainless steel heat exchanger with larger waterways to ensure maximum heat transfer. The product’s design ensures flexibility while […]

Read More
[gravityform id="35" title="false" description="false"]