As many growers and garden center retailers can attest, houseplants and tropicals are having a moment, and that excitement was apparent at the 2019 Tropical Plant International Expo.“There is electricity in the air, and it’s an optimistic show,” says Jared Hughes, owner of Groovy Plants Ranch based in Marengo, Ohio. “People are excited.” TPIE, which featured 400 exhibitors and 6,488 attendees, took place Jan. 16 to Jan. 18 at the Broward County Convention Center in Fort Lauderdale, Florida. Theresa Riley, owner of Rockledge Gardens in Rockledge, Florida, served on the TPIE committee for several years, and said the 2019 show was a standout. “I really think this year is one of the best I remember in a very long time! Lots of positive vibes and buzz,” she says. We spotted interesting plants, festive people and creative displays on the show floor. Here are just a few highlights.
After graduating from The Ohio State University in 2016 with a degree in horticulture and a minor in agribusiness, Tanner Cole spent two-plus years working for Dümmen Orange in marketing. But in 2018, Cole left the breeder to work as the new general manager at Corso’s Perennials in Sandusky, Ohio. It’s a move that he says excites him because it gets him working directly with plants again.
Greenhouse Management: What about growing specifically made it something you wanted to come back to?
Tanner Cole: I’m a plant geek at heart — a total nerd when it comes to horticulture. When you work for a plant breeder, there is no shortage of administrative, logistical and business items to distract your focus away from the horticultural magic of plants and flowers. With Corso’s, it gives me the opportunity to get even more hands-on experience with the plants, get back in the greenhouse a bit more, and get back to my roots — pun intended.
GM: What do you feel like you can take from your time working at Dümmen Orange and apply to your work at Corso’s?
TC: Without a doubt, Dümmen [Orange] has some incredibly competent, intelligent and accomplished individuals on their payroll. In my time there, I was privy to the knowledge of those individuals and I definitely used that to my advantage. Dümmen Orange launched my career, there’s no denying that. Specifically, I think Dümmen [Orange] does a great job managing enormous projects like acquiring a broker, or building the most elite archive facility in the world, just to name a few examples. They take those projects and divide, delegate and shepherd them from vague concepts to concrete realities. [In] my two and a half years there, [I] saw significant involvement in similarly massive projects, and without that experience under my belt, I’d be hard-pressed to move along some of the large projects I’ve been working on at Corso’s as quickly as I have.
GM: Has the industry done a good job of enticing younger people to make horticulture a career?
TC: I don’t think the industry has done a particularly good job of enticing youthful people. I think it partially boils down to economics. If you go to a good educational institution — let’s say a land-grant university like Ohio State or others — and pay $15,000, $20,000 a year to graduate and make $25,000 starting out, there’s something with that math that doesn’t quite add up, right? I think collectively as employers, we haven’t done a good job of realizing the economic reality of our young-talent problem. Simultaneously, we are always talking about labor scarcity and cutting labor costs, so there is a balance to be found. But I also think some academic institutions have done a poor job of preparing horticulture students for the actual industry. In certain regards, when I graduated [from Ohio State], I was surprised at how much I didn’t know about the industry as whole. I knew a lot about plants. But I didn’t really understand the distribution chain, the importance of effective logistics or the impact of cannabis on the industry. As a young person myself, I’m trying to champion young people. I’m trying to draw people into Sandusky. There’s this stereotype that Millennials only want to live in cities and will never appreciate horticulture as much as generations before us — I don’t think that’s the case whatsoever. We just need to tout the benefits that our industry has to offer.
For growers across the U.S. and Canada, fruitful perennial plant production requires both precise planning and keeping up to date with the latest trends. According to two experts, that can involve adapting their growing strategy and knowing what plants customers are looking for.
Two key changes in growing strategy
Karl Batschke, the global project manager for Darwin Perennials, says the way growers are producing perennials is shifting in two areas. The first is that many growers are sourcing young plants differently. According to Batschke, some are relying less on third-party sourcing, and instead using unrooted cuttings more frequently because of a lack of consistent availability of young plants.
“Growers can bring in unrooted cuttings, propagate [them] and have success themselves,” Batschke says. He adds that pricing pressure — especially from big box stores — is lowering margins across the supply chain.
Secondly, Batschke says that some growers are changing when they are growing perennials to avoid issues caused by inclement weather. Historically, he says, perennial growers will plant a 72-cell liner in August. Now, he says some are creating their own 21-cell liner in the winter in a more controlled environment with heat. The benefit, Batschke says, is that growers can worry about weather-related issues for six to eight weeks instead of several months.
“It’s the biggest game changer in the perennial world,” he says.
Perennial market trends
Bob Blew, the vice president of Centerton Nursery in Bridgeton, New Jersey, says the nursery sells exclusively to independent garden centers (IGCs). According to Blew, one of the most popular plants on the market right now is one that has been trending for the past several years.
“Believe it or not, echinacea are a pretty strong segment of the market,” he says. “I’m not sure its market share is growing as much as it was five or six years ago. But five or six years ago, everyone was asking, ‘Well, what’s the next echinacea?’ and [now], that plant is still driving a lot of summertime sales.” Blew says the echinacea has maintained its status because it’s easy for consumers to care for and the bright colors bred into it draw people in.
“We’ve also seen a bit of a push towards natives,” he says. “You can fly the native flag with echinacea. And we’ve seen a push towards succulents. It’s largely the same thing as with echinacea — there are great colors and they are fairly low care.”
As he looks ahead toward the next perennial market drivers, Blew monitors the latest trends. He says that when he talks to IGCs, the latest introductions are what generate increased sales.
“If one is slightly improved and new, we know we can sell it because it is new,” he says. “It doesn’t matter what the plant is.”
Blew is also eyeing current color trends. Among his top-20 selling perennials in the last year, he says most are utilitarian plants for landscapes. Purple or lavender are the most popular colors, and vivid colors currently outshine pastels. He also says the 2019 Pantone Color of the Year, Living Coral, “hits the nail on the head” as far as what consumers want.
There’s just one problem: It’s not a widely available color.
“It’s a color that, outside of a couple roses we grow, is really hard to come by,” Blew says. “It’s a color that’s not found as much in nature. A lot of plants flirt with that color, but don’t quite get there.”
What makes a successful perennial grower in 2019
Growers are setting themselves up for success, Batschke says, when they know which plants they can propagate themselves and which plants they need to source from a third party are setting themselves up for success.
“They have kind of a hybrid system,” he says. “They leave the more specialist items to the professional propagators, and [the growers will] do the easy stuff [in house]. It’s not an all-or-nothing thing, but I see a lot of really big growers relying on professional propagators when they know they’ll struggle with [certain plants].”
Batschke says one of the common plants growers leave to the propagators is dianthus; its unrooted cuttings have a one-year quarantine period upon entering the United States. Other crops often purchased through third-party suppliers are tissue-culture-raised products such as echinacea and hostas. Examples of products that growers may have more success propagating themselves are groundcovers such as phlox and sedum.
“Those products are some of the lowest-margin items,” Batschke says. “By doing it themselves, growers save money.”And if growers can save money and get customers the perennials they want, then everyone wins.
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Recirculating irrigation water is a method that can reduce runoff and soil pollution. Instead of letting the leachate drip from the benches or ground beds into the soil, the water is collected, stored and recirculated at the next watering.
Besides the benefit of reducing runoff, there are several other advantages to subirrigation:
- Less labor. Most of the time needed for setup and operation of an irrigation system is eliminated.
- Uniform plant growth. Every plant gets the amount of water it needs.
- Less water is needed. A savings of 50 percent or more can be realized.
- Less fertilizer is needed. Without leaching, fertilizer rates can be reduced 25 to 50 percent.
- Lower humidity. Because the leaves remain dry, there is less evaporation.
- Lower prevalence of diseases. As there is little water movement between containers, the spread of disease is limited.
- Increased space efficiency. Tray and floor systems containers can be spaced more efficiently.
Challenges to ebb and flood irrigation include:
- Greater system cost. Depending on the system, cost can be $10 to $20/square feet of growing area.
- Learning curve. Production techniques are different than conventional production.
- Greater monitoring of irrigation solution. Both EC and pH must be monitored on a regular basis.
In addition to the troughs, benches or flood floors, the basic system contains tanks to collect and hold the water or nutrient solution, pumps and piping to move the water and a control system that regulates when the system is to operate and for how long. Concrete or polyethylene tanks are sized at ½ to 1-gallon capacity/square foot of growing area. Two or more tanks are usually installed to have storage for water and nutrient solutions. PVC pipe and fittings give good service for handling the water or solution. Stainless steel centrifugal pumps are used to handle the nutrient solution and a filter is installed to screen out materials such as growing mix and leaves, timers or a controller are needed to adjust the length of time the pumps operate.
Trough system: This system allows the use of existing benches, therefore reducing cost. PVC or aluminum troughs that are wide enough for the pots to sit in are placed on the benches. Benches are adjusted to provide a slight slope so the water drains from the supply to the discharge end. Water is pumped from the reservoir tank under the benches to the high end of the troughs. A cross gutter at the discharge end collects the water and piping carries it back to the holding tank. Water from the holding tank is then pumped to the reservoir tank, thus the closed system. Trough systems can also be suspended from overhead trusses to gain additional growing space.
Ebb and flood on benches: In this system, the benches remain level and plastic liners are inserted to contain the water. Water from a reservoir is pumped through a two-way valve to the bench. When the level of water reaches ½ inch to 1 inch and the growing media in the containers has absorbed as much as needed, the valve reverses and the remaining water is siphoned out. Partial saturation by restricting the time water is left in the bench can reduce the need for growth regulator chemicals.
Flood floors: Flood floors are becoming popular for growers that produce large numbers of the same-size plants. In this system, there are no aisles and all the area can be used for plants. A concrete contractor with experience in flood floor installation is best as the concrete has to be placed accurately. This makes up about 75 percent of the total cost. Floor heat is installed to provide rapid drying of the floor surface when the water is drained and to provide an ideal root zone temperature. Gutter-connected greenhouses are usually divided into bays at the post lines to provide separate zones to reduce the size of the reservoirs needed. The finished floor slopes about ½ to ¾ inch from the post line to the center of the bay. A supply/drain pipe is installed below floor level and a slot or holes are installed after the floor is finished. The concrete floor along the length of the bay is installed level with a laser screed. Reservoir tanks can be located below the floor in an accessible pit or above ground in an adjacent bay.
Subirrigation systems usually have a payback of three to four years depending on the season of use and the labor saved. In some states, subirrigation systems are eligible for grant funds from USDA NRCS programs. Information about NRCS programs is available here
John is an agricultural engineer, an emeritus extension professor at the University of Connecticut and a regular contributor to Greenhouse Management. He is an author, consultant and certified technical service provider doing greenhouse energy audits for USDA grant programs in New England. firstname.lastname@example.org
Pesticides (insecticides, miticides, bactericides and fungicides) are still widely used in greenhouse production systems to alleviate problems with insect and mite pests, and diseases. However, continual reliance on pesticides can promote the development of pesticide resistance. Pesticide resistance is a very important factor that greenhouse producers must take into consideration when dealing with pests (insects, mites and diseases) in greenhouse production systems.
This article is the first in a series of six articles we plan to develop in 2019 and 2020 focusing on pesticide resistance and resistance management for insect and mite pests, and diseases. The first article of the series describes pesticide resistance as it relates to arthropod (insect and mite) pests and plant pathogens, highlighting the differences and similarities.
1. Pesticide resistance: insect and mite pests
Resistance is the genetic ability of some individuals in an arthropod (insect or mite) pest population to survive an application or applications of pesticides (insecticides or miticides). In other words, the pesticide(s) no longer effectively kills a “high” number or percent (>90%) of individuals in the insect and/or mite pest population. Resistance develops at the population level and is an inherited trait. Surviving insect or mite pests can pass traits (genetically) to their offspring (young) or next generation, thus enriching the gene pool with resistant genes. In addition, resistance indicates a change in the genetic composition of an insect or mite pest population in response to selection by a pesticide (insecticide or miticide) over time. “Selection pressure” for resistance increases as application frequency increases, especially when insecticides and miticides with the same mode of action are applied in succession. Moreover, the frequency in which resistant genes occur in a pest population determines the rate that resistance can develop.
So, every time a pesticide (insecticide or miticide) is applied, this places “selection pressure” on insect and/or mite pest populations, which consequently alters the frequency of resistant and susceptible individuals in the population. Insect and mite pest populations can develop resistance to pesticides using different resistance mechanisms. The two most common mechanisms are based on metabolic and physiological resistance. Metabolic resistance involves degradation of the active ingredient by an insect or mite pest. For instance, when a pesticide enters the body, specific enzymes detoxify or convert the active ingredient into a non-toxic form. The active ingredient is then excreted out with other waste products. Physiological resistance occurs when an insect or mite pest modifies or alters the target site of the pesticide, which decreases sensitivity to the active ingredient at the physical point of attachment (lock and key scenario). One form of resistance that can occur among resistant insect and mite pest populations is referred to as “cross resistance.” Cross resistance is based on a single resistance mechanism conferring resistance to pesticides in the same chemical class and/or having similar modes of action. Cross resistance is common among aphid and spider mite populations.
The biological factors responsible for promoting resistance in insect and mite pest populations are listed below:
- Short generation time
- Multiple generations per season or cropping cycle
- High female reproductive capacity
- Broad range of host plants fed upon
2. Resistance management: Insect and mite pests
The primary way to alleviate insect and mite pest populations from developing resistance is to rotate pesticides with different modes of action. The mode of action is how a given pesticide (in this case, insecticide or miticide) affects the metabolic and physiological processes of an insect or mite pest. There are two mode of action types affiliated with insecticides and miticides: narrow and broad spectrum. Narrow spectrum or site-specific mode of action pesticides are active on specific target sites in the central nervous system or enzymes associated with metabolism. Broad spectrum mode of action pesticides are active on a variety of target sites or possess multiple modes of action. The modes of action of insecticides and miticides used in greenhouse production systems are available on the Insecticide Resistance Action Committee (IRAC) website (irac-online.org). In addition, the mode of action of a product is listed on the package as a number (e.g., 5, 6 or 28) or combination number and letter designation (e.g., 4A, 7A or 21A).
3. Pesticide resistance: plant pathogens
Dr. Cloyd’s description of why arthropod pests can become resistant to a product are about the same as the reasons for plant pathogens becoming resistant. Bacteria can have a generation time of merely 20 minutes. Fungal generation times range dramatically with some fungi-making spores (reproducing) in a few days to weeks. In addition, some fungi have both asexual and sexual reproduction — like some insects. In this case of sexual reproduction, the genes are essentially recombined, making the possibility of resistance much more likely.
Some plant pathogens also have a very broad host range, which makes it easier for resistance to develop: Botrytis, some bacteria like Erwinia, some powdery mildews and Rhizoctonia and Pythium causing root rot. Others are narrow, like some leaf spots and Fusarium wilt.
The spread of disease is largely passive for plant pathogens, unlike insects, which can move from site to site. Wind (or fans), handling by workers and water are the most common way some plant pathogens get around our growing areas. Examples of plant pathogens moved by water are Pythium and Phytopthora. Those easily moved by wind or fans are Botrytis, downy mildew, rust and powdery mildew. This method of dispersal means that somebody else’s resistance can become yours.
4. Resistance management: plant pathogens
For plant pathogens the keys to resistance management involve a series of issues. First and foremost, the cause of symptoms must be determined. Using the wrong product for a disease results in no control, which can be confused with resistance. Use of the correct product at the correct rate and interval are the best ways to make sure you do not provide pressure on the fungus or bacterium, resulting in the development of resistance. It is well-known that using lower than a lethal dose of a product targets the weakest or most sensitive individuals and builds the proportion of the population with a high level of resistance until it is the only thing present.
Application of a product too often in a program exposes the fungal or bacterial pathogen to a single mode of action, resulting in resistance development the same as insects and mites.
This is especially true if you are using a narrow mode of action product, which does the same thing to plant pathogens as arthropod pests. Tank-mixing or alternating products with the same mode of action does the same thing. It is always necessary to know the FRAC number to avoid this mistake by alternating numbers in successive applications. Using a product with multiple modes of action, which can come from a single active ingredient or a pre-mix of two or more ai’s, is a good way to avoid resistance development.
The next article in the series will address the history of pesticides in regard to the development of resistance to older and newer pesticides.
Raymond is a professor and extension specialist in horticultural entomology/plant protection in the Department of Entomology at Kansas State University. His research and extension program involves plant protection in greenhouses, nurseries, landscapes, conservatories and vegetables and fruits. email@example.com or 785-532-4750
Dr. A.R. Chase is president of Chase Agricultural Consulting. She has more than 35 years’ experience in research, diagnostics and practical consulting in plant pathology. She has been retired from the University of Florida – Mid Florida Research and Education Center in Apopka since 1994, but remains on staff as a professor emeritus. firstname.lastname@example.org or 928-649-0400