Michael Turner was living in Boston, studying political science as a graduate student, when he took a summer job working at a nursery in Lexington, Massachusetts. The job changed his entire career path. 

“I fell in love with greenhouses and growing,” he says. “And I hated graduate school.” 

Soon after, Turner moved back to his native North Carolina and started a part-time cut flower business while working full-time as a produce buyer for Whole Foods and other grocery chains. After a few years, he was able to commit to flower growing full-time and opened Sarah & Michael’s Farm, where he grows lilies. The business has been located at the same site in Durham, North Carolina since 1997. Now, his business operates year-round and sells to customers such as Whole Foods. 

A key part of Turner’s business is his use — and reuse — of a coconut coir growing media; he recycles it for multiple production cycles. The idea to use coir, and recycle it, came from a grower back near where he took his first growing job. In 2006, he visited a lily grower named Fred Greene at Stow Greenhouses in Stow, Massachusetts. Greene used and recycled coconut coir and showed Turner the ropes. Soon after, he switched Sarah & Michael’s Farm's production to the material and now only grows in coconut coir. 

“We had gone through every conceivable mix of growing media,” he says.

The advantages of coconut coir 

Turner plants lilies in the crates that the bulbs are shipped in — a common Dutch growing method, he says — in the coconut coir. Each greenhouse is full from end-to-end with just enough room left to properly access and monitor each lily as it grows. 

Turner, who sources his coconut coir from Sri Lanka through a Canadian importer, says the biggest reason coconut coir works so well is because it is a “superior rooting media.” 

“The lilies just thrive in it,” he says. “Growing lilies is about growing really good roots, and lilies root really well in coir. And it matters that I am growing cut flowers and not something else because coir itself is a fairly light media. If it were a potted plant, I would have to worry about it tipping over.”

Additionally, Turner says coconut coir, unlike other growing medias he’s used, holds up well when steamed, cooled off and then reused. When he begins the recycling process, the coir fibers hold up well to the heat. To recycle it, a small percentage (the exact percentage depends on the week) of fresh coir is added to the used coir to keep the structure intact.

“It holds up much better than peat moss, for instance,” Turner says.

He adds that it helps that he has a consistent supply of coir; it hasn’t caused the issues he’s seen other lily growers face. For instance, Turner says high salt and potassium levels are a possible issue in coir, and if one or both is prevalent, it will negatively impact plant growth. 

“That’s a natural property of the coir,” he says. “A good supplier will take care of those issues.” 

Cost benefits

Turner says that importing coir from Sri Lanka a few times a year is “very expensive,” and it’s the main reason why he recycles his instead of using it and getting rid of it. Each year, he buys three containers for a total cost of around $35,000.

According to Turner, steaming the material also allows his business to avoid using any pesticides in the greenhouse because it preventively rids the coir of pathogens. Additionally, because of year-round aphid pressure in North Carolina, the coir cannot be used more than once before it is steamed. Other lily growers in the Netherlands and in Canada who he’s talked to use their coir twice before either recycling it or pitching it. 

“If we weren’t recycling, instead of ordering three containers a year, we would be ordering four times that many containers at least,” he says. Right now, coir is Turner’s sixth-highest operational cost; it would likely be No. 1 or No. 2 without recycling.

Originally, Turner was steaming the coir in the crates they were grown in, but found that it caused the crates to break down and be unusable. In 2012, he switched to using a system where the coir is transferred into a bunker away from the greenhouse. There, it sits on top of piping that pushes steam up through the coir, refreshing it to be used again. The initial cost for the piping was high in the short term, but Turner feels it’s made the process more sustainable for his business.

“We know what’s in our soil,” Turner says. “We’ve taken out that wild card. When you buy soil, you hope you have a reputable supply. But by keeping it in-house so to speak, we feel like we have a lot better control over it. And the lilies love it.” 

With winter here, so comes the time for forcing bulbs. As with almost every other floriculture crop, plant growth regulators (PGRs) are applied to control growth and improve appearances. Foliar sprays may be used to apply PGRs, but it can be a challenge to get adequate coverage when shoots are emerging and there is limited leaf area to absorb the active ingredients. Substrate drenches are a very effective option for applying PGRs to bulbs, but can be a labor-intensive application method. Bulb dips are an effective and efficient way to treat bulbs with PGRs.

The bulb dipping process is straightforward (Fig. 1). First, bulbs are removed from cases and cleaned of excessive amounts of packing material (i.e., peat moss) they were in. Next, the bulbs are submersed inside a solution — consisting of ancymidol, flurprimidol, paclobutrazol or uniconazole — and allowed to absorb the PGR. Then, the bulbs are removed from the solution, excess solution is allowed to drain and the PGR application is complete.

There are several advantages to this application technique. First, it is an effective way to treat a large quantity of plants efficiently. The only limitation is the size of the container you place the bulbs in and your ability to remove them from the solution once the soak is over. Second, the application environment does not matter. It can be warm or cool, sunny or cloudy — it doesn’t make a difference. However, you’ll want to monitor the PGR solution temperature, as discussed later.

Third, the application timing is flexible. For example, bulb dips can be performed from an hour up to a week prior to planting the crop. Finally, it is an efficient use of PGR product, as the solution can be reused to treat numerous batches of bulbs.

That is not to say there are no challenges to bulb dips. Since bulb dips are performed prior to planting the crop, there are some limitations or precautions that should be taken to avoid problems. First, you don’t know what the environment is going to be like when you force your bulbs. Are you going to be faced with weather that is warmer and sunnier than usual, or are you going to have cooler, overcast conditions? This can make it challenging to try and get exactly the growth control you need with a single PGR application. In general, with any pre-plant PGR treatment like bulb dips or liner dips, using a lower concentration of active ingredient can help avoid over-regulation of growth when growing conditions are suboptimal, and follow-up applications can be made on an as-needed basis.

Another challenge can be achieving uniform control. When bulbs are stored in peat moss in their cases for transport, storage and cooling, some bulbs lose water and dehydrate. When placed into PGR solutions, those dehydrated bulbs soak up more solution than intended and will exhibit excessive growth control from the excessive solution. To avoid this, soak all bulbs in clear water prior to placing them into the PGR solution. The hydrated bulbs will take up little, if any, water, whereas the dehydrated bulbs will soak up as much as they can. In the end, both bulbs end up back at a similar degree of hydration and should absorb similar amounts of PGR when dipped.

You also want to watch your PGR solution temperature. If the PGR solution is too cold or hot, it can diminish PGR uptake by the bulbs. One simple solution is to get your water for the solution ready the day before treating and let it come up (or drop down) to ambient temperature in the greenhouse or headhouse. Alternatively, use a tempered water source.

While we call it a bulb dip, it is a suitable application method to apply PGRs to not only bulbs, but corms, tubers and rhizomes. Consider trying this flexible, efficient and effective method of applying PGRs on other species you grow starting from these types of storage organs. As always, conduct on-site trials under your growing environment, cultural practices and specific cultivars to see what works best under your conditions.

Christopher is an assistant professor of horticulture in the Department of Horticulture at Iowa State University. ccurrey@iastate.edu

Twospotted spider mite, Tetranychus urticae (Fig.1), is one of the most destructive mite pests of greenhouse-grown horticultural crops. Twospotted spider mite populations are difficult to manage due to the following characteristics: 1) they feed on a wide-range of plants; 2) females have a high reproductive capacity; 3) they have a short life cycle (egg to adult); 4) multiple generations can occur simultaneously; and 5) rapid population growth. Therefore, miticides (acaricides) are routinely applied to suppress or mitigate twospotted spider mite populations from reaching damaging levels, which will reduce substantial damage to plants. However, the twospotted spider mite can rapidly develop resistance to many pesticides (insecticides and miticides).

A number of commercially available miticides are known as mitochondria complex electron transport inhibitors or METI. The mitochondrion (plural: mitochondria) is a membrane-bound organ that is a major site where chemicals in food are converted into energy in the form of adenosine triphosphate (ATP) that is utilized in metabolic processes in cells. In some cases, cytochrome proteins may be involved, which facilitates electron transport and allows for oxidation-reduction reactions (reactions that involve gaining or losing electrons) to occur.

Miticides that are classified as METI include: acequinocyl (Shuttle), bifenazate (Floramite), cyflumetofen (Sultan), fenazaquin (Magus), fenpyroximate (Akari), and pyridaben (Sanmite). In general, the METI are active on all life stages of the twospotted spider mite including the egg, larva, nymph, and adult. However, studies have shown that METI miticides are more active on the nymph and adult life stages of the twospotted spider mite. Furthermore, METI miticides are only active as contact miticides; they do not have translaminar activity (material penetrates leaf tissues and forms a reservoir of active ingredient within the leaf; thus providing activity even after residues on the leaf dry) as do some miticides such as abamectin (Avid), chlorfenapyr (Pylon), etoxazole (TetraSan/Beethoven), spiromesifen (Savate) and spirotetramat (Kontos).

The basic mode of action of the METI is through the reduction of energy production in the mitochondrion by disrupting or inhibiting the production of ATP, which leads to rapid paralysis and death as a consequence of cellular energy starvation. The mode of action of the METI involves activity on three different complexes (I, II, and III) (Fig. 2). Below are the three complexes and how the miticides act on these complexes along with the associated active ingredients (in parentheses):

• Complex I: inhibit nicotinamide adenine dinucleotide hydride (NADH) dehydrogenase associated with electron transport or act on NADH by binding to coenzyme site Q (CoQ) reductase (fenazaquin, fenpyroximate and pyridaben)
• Complex II: inhibit functioning of complex by affecting the active site after being metabolized to AB-1 (cyflumetofen)
• Complex III: bind to the quinone oxidizing (Qo) center in the cytochrome bc1 subunit (acequinocyl and bifenazate)

Tolfenpyrad (Hachi-Hachi) is also a METI acting on Complex I but is not a miticide, with registration for use against aphids, mealybugs, thrips and whiteflies. Table 1 presents the pesticides (insecticides and miticides) designated as mitochondria complex electron transport inhibitors (METI) along with the complex target site in the mitochondrion, and the Insecticide Resistance Action Committee (IRAC) designation.

The METI miticides are effective against most life stages (i.e. egg, larva, nymph, and adult) of the twospotted spider mite; however, it is important to avoid using METI miticides in succession (back-to-back) in spray programs to prevent twospotted spider mite populations from developing resistance to this mode of action.

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. rcloyd@ksu.edu or 785-532-4750

When Jen DeVere first encountered horticulture at a high school job fair, she thought working with plants sounded like a stress-free career. Now, after more than a decade in the field, she understands that greenhouse growing isn’t always easy — in fact, it can be a hot, dirty, demanding job — but the rewards are well worth the labor.

“I tried working in an office and it’s just not my thing. I need to be outside,” says DeVere, a section grower at Casa Verde Growers in Columbia Station, Ohio. “Watching the transition from a tiny plant with two leaves into a giant bush — and knowing that these two hands helped guide it — that makes me proud.”

Finding a fit

After taking a hort tech prep class in high school, DeVere enrolled in The Ohio State University Agricultural Technical Institute to explore opportunities in horticulture. She “fell in love with the greenhouse program,” and graduated in 2005 with a two-year associate degree of applied science in greenhouse management and production.

DeVere worked for wholesale growers near Columbus and then Dayton before finding a job at Heartland Growers in Indiana as a propagation section grower. But then, feeling homesick for her family back in northern Ohio, DeVere began looking for jobs closer to home. In 2014, she found a perfect fit as a section grower of finished plants at Casa Verde Growers, a wholesale supplier for Petitti Garden Centers, which operates nine retail locations across northeast Ohio.

DeVere oversees five acres of production at Casa Verde, which operates 28 acres under cover and about another 10 acres outdoors. She’s responsible for growing finished poinsettias, Easter lilies, herbs, cyclamen and “hot annuals” including dahlias, begonias, impatiens, lantana and — her favorite — flowering vinca.

Working from home

When DeVere arrives each morning, her first stop is a computer in the office that monitors the greenhouse climate. Most days, she accesses these environmental controls before she even leaves her house, using an app on her phone to check in while she’s drinking her coffee.

“It’s helpful having the ability to see what’s going on and make adjustments,” she says. “I’ll be sitting [at] home on a Sunday, and during halftime of the [Cleveland] Browns game, I’ll think, ‘It’s [awfully] sunny. How hot is it in the greenhouse?’ so I can pull it up, and see that the shade curtains aren’t closed, and manipulate it from home.”

Through the app, DeVere can also control flood floors and automated watering booms in her section of the greenhouse.

“I’m often flooding poinsettia floors from home in the morning, because I don’t want those to be on when [my crews get to the greenhouse] if I want to have people walking around,” she says. “Using that automation to irrigate ahead of time is super helpful.”

Making the rounds

After checking the environmental controls, DeVere makes her daily rounds.

“I’m walking the crop in its entirety, every single day, to make my to-do list: ‘This has to get spaced, this has to get pinched, this needs to get sprayed, this is going to get drenched,’” she says. “Then I’ll prioritize that list and either sic my crews on it or do it myself.”

At peak season, DeVere has three crews (a total of eight assistants) working with her, which shrinks to a crew of two in the offseason. She checks in with them throughout the day “to make sure they know what they’re doing, they’ve got all the supplies they need, and they don’t have any questions,” she says.

A key to DeVere’s managerial style is that she doesn’t ask crews to do anything she wouldn’t do herself — whether it’s trimming herbs or scrubbing out the flood floor tank.

“I like being involved in the nitty-gritty part,” she says. “If I go home at the end of the day and my hands aren’t dirty, I haven’t been doing it right.”

Slowing down

Every growing season brings new challenges, but DeVere encourages other growers not to lose patience.

“You’ve got to remind yourself that one bad crop doesn’t make you a bad grower,” she says.

Growers should feel reassured knowing they’re not alone, she says. Between former colleagues, social media groups and peers she’s met at symposiums, DeVere has built a strong network she can turn to for advice when she encounters pests, diseases and other issues.

“There are so many people you can reach out to who are in similar structures, growing similar crops, dealing with the exact same problems,” she says. “The connectivity we have as growers is really neat — it’s a nice little club.”

She also reminds growers to pause and look at the big picture, considering how plants will brighten a customer’s day.

“It’s so easy to get stressed out and beat yourself up because this is coming in late or these bugs are attacking, but someone’s going to buy that plant and it’s going to make them happy,” she says. “Stop for a second and look at what you’ve created; look at the beauty around you and the joy you’ve created with those crops.”

Brooke is a freelance writer living in Cleveland.