Photo courtesy of PARsource

LED lighting has become a popular option for many greenhouse growers over the past several years. Greenhouse Management recently spoke to PARsource Director of Sales Jud McCall about the advantages of LEDs, the current ROI for LEDs and more.

Greenhouse Management: How have LEDs changed the lighting market for growers?

Jud McCall: Horticultural lighting options for CEA [controlled environment agriculture] growers have never been more diverse and abundant than what is available for the commercial grower today. Among the options available, LED lighting continues to gain interest and market share due the unique advantages it has to offer over older technologies. We have seen the adoption of LEDs in our homes, cars and places of work. Why would we expect it to be any different in our greenhouse or indoor farm?

GM: What are some of the key benefits LEDs have to offer over more traditional lighting options?

JM: One of the most common benefits of using LEDs is operational cost savings. This not only entails direct electrical savings, but also secondary savings when it comes to reduced heat load and optimizing environmental conditions for cultivation. However, just as important if not more so, are the benefits LEDs offer with targeted PAR and PBAR [plant biologically activated radiation] spectrums that minimize wasted photons compared to other types of lighting. There is no better option than LEDs when it comes to targeting specific parts of the light spectrum that in turn elicit the desired plant state and photomorphogenic response. This can translate into reduced harvest time, more weight and other characteristics for a crop that can command a premium when taken to market.

GM: What is the current ROI on LEDs and how does it compare to other lighting options?

JM: Return on investment for LEDs versus HID systems is a frequent debate, and beyond the potential for increased crop profits the answer depends on the particular application and usage. To be clear, LEDs are the more expensive option up front. An ROI calculation needs to take into account more than just energy savings. Very long system lifespans with no maintenance or lamp changes versus HID systems is a compelling point with regard to labor and replacement cost. Also, one must factor in seasonal usage and greenhouse DLI where they are located. For example, a greenhouse grower in the state of Washington with a February greenhouse DLI of 4 moles per a day is probably going to fully realize ROI in half the time of their counterpart in a greenhouse in South Carolina.

GM: What makes PARsource’s LEDs different than others on the market?

JM: PARsource, a Hydrofarm company, has decades of experience when it comes to horticultural lighting. Last year, we unveiled our new line of PHOTOBIO LEDs, which were met with great enthusiasm and customer interest. These lights were developed in partnership with SANANBIO, a world leader in vertical farming automation and controlled environment agriculture under SANAN Optoelectronics, one of the largest LED chip companies in the world. We combined the experience, research and expertise from both companies to bring to market a range of efficient, quality LED systems that present an unparalleled value for all types of CEA growers. Initial customer installations have gone well, and we look forward to many more as the year unfolds.

Photo courtesy of Hawthorne Gardening Co.

Greenhouse Management: How does the ROI for HPS lighting compare to other options?

Mike Anderson: The only competition for HPS is LED. LED is still four to six times the initial investment and can’t have lower lifetime cost. Yes, LED chips last a long time, but the drivers do not. Most likely, the LED unit will not be repaired, it will have to be replaced when the driver fails. LED is becoming interesting when there is government subsidy to offset the higher initial costs, but after the subsidy, it will be expensive to replace. LED is useful where there are temperature limitations in the growing space or where there is limitation on power availability. When calculating ROI in a normal operation, HPS will always have more advantages than LED. In the recent past (one to two years ago), the real output of the LED fixtures was 2.1 - 2.3 umol (micro moles) per watt. At these efficiency levels, LED systems needed to consume nearly the same or slightly more power than HPS. Recently, we see fixtures with 2.7 or more micro moles per watt, but still the ROI is less favorable when compared with HPS.

GM: What are the benefits of using HPS lighting, even as other options have become more popular?

MA: HPS is one solution but may not be the best solution depending on the particular needs of the grower. HPS is a proven and reliable technology which can be used in all kinds of cultivation, from flowers and plants to vegetables and fruits. HPS provides the best return on investment, lowest initial and lifetime costs, and is a mature and proven technology that is easy to maintain. We have decades of lighting design experience utilizing world-class HPS reflectors to create the best light uniformity in the market for greenhouse or indoor facilities.

GM: Have HPS lights become more efficient in recent years? If so, what does that mean for growers?

MA: Growers continue to ask for more light per fixture to maximize plant growth at lower cost. A rule of thumb is that increasing the amount of light available to the plants by 1% (measured as PAR) correlates directly with a 1% increase in plant production. We continue to work with our vendors to drive efficiency and lower cost for the grower. Lamp cost is relatively low, so the next large gain may be to increase light output even if it lowers lamp life so that growers benefit from increased plant yields.

GM: How can Hawthorne help growers find the right lights for their greenhouses?

MA: With Gavita, a division of Hawthorne Gardening Company, we are the global market leader in the horticultural light business and we know what light can do for each specific crop. Hawthorne has a technical services department that was created to work with new and existing growers. We meet with growers to design the best solution for each growing situation, taking all growing, environment and legislative aspects into consideration. In this way, we can create a total light calculation, an ROI and offer the right solution for every grower around the globe. Our broad product portfolio makes it possible to select the right fixture for the application.

Sven Springintveld, general manager for Gavita International b.v., and Arjan Pauw, horticulture international sales director Horticulture for Gavita International b.v., contributed to these answers.

Photo courtesy of Premier Tech Horticulture

Greenhouse Management: How has the growing media market changed in the past few years?

Ed Bloodnick: With the economic downturn some years ago, there was a consolidation of the industry and the grower market. We see more diversification into other crops like edibles, organic crops and more large ‘ready made’ planters and assorted variety baskets for instant color. For all markets, the cost and availability of labor has had a big impact in all commercial growing. Because of this, we see more commercial greenhouses moving towards automation and an increase in the use of commercially prepared growing media. Many operations have converted to large, bulk package format to reduce handling and labor. Although the floriculture market is still the largest market, it has become more selective in terms of the types and quality of products it requires. These are the big changes — and the growth we have seen in the past few years.

GM: Premier Tech Horticulture and the PRO-MIX brand have some products that include active ingredients such as mycorrhizae and helpful bacteria. What are the advantages of buying growing media with active ingredients already present?

EB: While there are regulatory and registration requirements to sell active ingredients, unfortunately there is not enough monitoring across the market to check for quality. There are differences between active ingredients in the market and it is important to compare apples to apples. What sets Premier Tech apart from other companies is that we produce growing media and the active ingredients we add to PRO-MIX products. This is attractive for growers since these active ingredients are produced by Premier Tech and we control the quality. The active ingredients themselves are high-quality and produced in aseptic conditions in a laboratory. We not only have the expertise in growing media, but we also have over 30 years’ experience in biological sciences to combine the technologies. We bring both of these technologies together in a pre-formulated blend so the grower doesn’t have to be concerned about blending the right amount, using equipment or reapplying it.

GM: How can a grower pick the right growing media for their business?

EB: If a grower is interested in a certain type of growing media, our sales and grower services teams go on site to visit them and understand what their needs are. Together, we select a product and demonstrate its value to be sure it’s the right product for their application. With growing media, it’s not one-size-fits-all. It depends on the type of crop, stage of development, container size, cultural practices and set-up in the greenhouse. With some crops, a one-size-fits-all solution may work. For example, a bedding plant crop is produced in a very short window where you buy a plug, transplant, you’re growing it for four to six weeks and it’s out the door. With longer-term crops, growing medium selection is a bit more involved to choose the right product for that entire crop cycle.

Photo courtesy of Syngenta

In late spring and early summer, growers need to mind their mildews. Greenhouse Management recently spoke with Nancy Rechcigl, technical services manager at Syngenta, about these diseases and the role fungicides play in controlling them.

Greenhouse Management: May and June can be difficult months for mildews. What is the difference between powdery and downy mildew?

Nancy Rechcigl: Downy and powdery mildew pathogens are both obligate parasites but differ in their symptoms and fungal classification. Downy mildews are Oomycetes while powdery mildews are Ascomycetes. This distinction is important when selecting fungicides for control.

Powdery mildews form white colonies on the surface of leaves, stems and flowers. They will likely appear in the spring or early summer when temperatures are 62-72° F and the relative humidity is 70 percent or greater.

Plants infected by downy mildew will have blotchy, discolored areas on the leaves, often within the veins. Under the right environmental conditions, sporulation creates a fuzzy coating under the leaves below the discolored areas. Systemic infections can also cause distortion of emerging leaves and flower buds, defoliation and stunted plants.

Temperatures from 50-72° F are favorable for most downy mildew fungi, but some can grow in higher temperatures such as those infecting roses (up to 82° F) and salvia (up to 90° F). All downy mildews require relative humidity greater than 85 percent for six-plus hours when the leaves are wet.

GM: How should these diseases be controlled?

NR: When the environmental conditions are conducive to disease development, powdery mildews should be controlled by alternating fungicides from FRAC Groups M, 3, 7+11, 9+12. Horticultural oils and some microbials can also provide suppression. Downy mildews should be controlled by alternating fungicides from FRAC Groups M, 4, 21, 40, 43, 45, U-49. Fungicides in FRAC Group 7+11 can protect against downy mildew as well as other diseases. Preventative applications are generally less expensive than curative, and result in higher plant quality.

GM: Why is product rotation so important to preventing mildews?

NR: Fungicide resistance can occur quicker in pathogens producing a lot of spores. Downy mildews are known to develop resistance very easily when exposed to a single active ingredient over time. To avoid resistance, you must rotate at least two to three products with different modes of action for each target problem. Programs should include a combination of products with systemic activity and contact or translaminar activity. A well-structured program will maximize each product’s strengths and leverage modes of action when they are most beneficial.

GM: What solutions does Syngenta offer that fit into a well-rounded fungicide program?

NR: Our downy mildew program includes the following fungicides: Subdue Maxx® (4) early in production, rotating to Mural® (7+11), Micora® (40) and Segovis® (U49). Our powdery mildew program includes the following fungicides: Daconil Ultrex® or Daconil Weatherstik® (M5) early in production, rotating to Palladium® (9+12), then Mural (7+11). In outdoor production rotations, include Concert® II (M+3) for powdery mildew.

GM: What resources does Syngenta have to help growers stop these diseases?

NR: Syngenta offers free, downloadable programs to help control powdery and downy mildew, as well as other common diseases at GreenCastOnline.com/Solutions

All photos are either the property of Syngenta or are used with permission.

©2019 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local Extension Service to ensure registration status. Concert®, Daconil Ultrex®, Daconil Weatherstik®, GreenCast^®, Micora^®, Mural^®, Palladium^®, Segovis^® and Subdue Maxx^® are trademarks of a Syngenta Group Company. Syngenta Customer Center: 1-866-SYNGENT(A) (796-4368).