Usually, this Production Pointers column is focused on the more technical aspect of greenhouse crop production. When I got ahold of the editorial calendar and saw that orchids were going to be one of the features of this issue, I got excited. Oftentimes during my lectures or in laboratories, after sharing some unique fact related to the crop when I am teaching, I often tell students that “Plants are cool.” Or, I am saying it out loud to myself. That is because it is a sincere sentiment. It is the sentiment that got me into horticulture, and the one that keeps me going day in and day out. But it is not just that plants are cool. It is that they are curious, puzzling, beautiful, biological organisms that are rewarding to work with.

If I could credit one crop for cultivating my passion for plants, I would credit orchids. I have driven hundreds of miles across the country with an orchid-loaded back seat and boarded planes with flowering plants in my arms. I have hiked bogs in northern Minnesota to find the showy lady’s slipper, and the wettest tropical forest in Costa Rica to find a flowering Brassavola and smell it at night. If not for orchids, I may not be where I am today.

There is so much more to a plant than simply its appearance. There are stories embedded in the botany and history that come with every plant. Let’s use slipper orchids as an example. The scientific names for two genera of slipper orchids (Cypripedium and Paphiopedilum) refer to a tryst that Aphrodite and Adonis shared; when a mortal came upon one of Aphrodite’s shoes that were left behind, the slipper turned into an orchid flower so no proof could be found. Then there is the story about the collectors who discovered Paphiopedilum rothschildianum, a status symbol in high societies; they purposefully reported an erroneous location (New Guinea) as opposed to its true home, one of three sites on Mt. Kinabalu on the island of Borneo.

The physiology of plants is what makes producing and enjoying plants interesting. If we just look at the propagation alone, orchids are fascinating. Many orchids are propagated vegetatively using tissue culture or by division, but seed propagation is also widely used for breeding and conservation. To propagate orchids by seed, their microscopic seeds are germinated in aseptic culture using ingredients like smashed banana and coconut milk or are inoculated with mycorrhiza to form a symbiotic relationship. Beyond growing and producing these plants, their structures have stories to tell. While we stare at a slipper orchid in wonder, insects also may be a little confused, but by design. They smell a sweet odor emanating from the flower, crawl down into the pouch to investigate and, while climbing out after some disappointment, get some pollen stuck to their back, which is transferred to the next slipper flower playing the same trick.

While I am singing the praises of these plants, orchids aren’t the only plants that captivate people. In fact, orchids really aren’t even the point of this article. They aren’t the only plants with unique names, history, physiology or growing requirements. All plants have these stories to tell. It’s more the passion that orchids instilled in me that helped open my eyes to the wide world of plants. Working with commercial greenhouse growers and university students, one of the questions I want to ask is, “What is your ‘orchid’?” I want to know what inspired them to work with plants and what keeps them doing it. Share your knowledge and passion with people and get excited. After all, plants are cool!

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

Fog is an alternative evaporative cooling method to the fan and pad system. Its advantages include more uniform cooling throughout the greenhouse, higher efficiency and lower maintenance costs. It also provides a method for cooling greenhouses that don’t have fans.

What is fog?

Fog particles are generally considered to be less than 50 microns (0.002”) in diameter. The particle size typically used in high pressure greenhouse fog systems is about 10 microns. Mist, on the other hand, is particles from 50 to 100 microns. As a comparison, human hair is about 0.004” diameter that equals 100 microns. Breaking one gallon of water into 50-micron droplets will produce about 68 billion droplets of fog.

Injected into the air, these tiny water droplets remain suspended until they are evaporated. The smallest particles vaporize almost instantaneously. The larger ones are carried by air currents, gradually becoming smaller until they are vaporized. Mist size particles are much heavier and take much longer to evaporate. These are more likely to fall out and wet the plant surface or saturate the growing medium. If they don’t evaporate before nighttime, the potential for disease increases.

How fog works for cooling

Evaporative cooling uses the heat from the air to change the water droplets into vapor. In this process, large amounts of heat are required. The resultant air is therefore cooler and more humid, an advantage to plant growth. For each gallon of water that is evaporated, over 9,400 Btu of heat are absorbed. Ventilation air is then used to carry the warm, moist air out of the greenhouse. This is replaced by drier outside air.

The potential for cooling is measured by the difference between the dry bulb and wet bulb temperature. A sling psychrometer or battery-powered hygrometer are low cost instruments to get these measurements.

If you're looking for an alternative evaporative cooling method to fan and pad systems, you may want to consider fog.

Although evaporative cooling is most effective in the Southwest where the air is dry and the difference between dry bulb and wet bulb is near 40° F on a summer day, it can also be quite effective across the rest of the U.S. In most other sections of the country including the humid Southeast, there is a potential for 10 to 20° F cooling below ambient during the warmest part of the day when the stress on the plants is the greatest.

Fog systems

Several methods are used to produce fog. A typical system uses a high-pressure pump, distribution piping and nozzles that break the water stream into very fine droplets. Piston pumps are needed to develop the 800 to 1200 psi pressure to get the 10 to 20-micron size droplets. Most systems available from irrigation equipment suppliers and labeled as fog systems operate at 50 to 100 psi and create a droplet size larger than 50 microns. They are really mist systems.

Copper, stainless steel and re-enforced flexible hose are used for piping. Diameter is frequently ¼” or 3/8” as water supply required is only 1 to 2 gallons/hour/nozzle. Distribution piping for cooling is placed above the air intake louvers or vents and a few lines of pipe are placed above the crop.

Plastic, ceramic and stainless steel are used for nozzles. Nozzles should have anti-drip check valves to prevent dripping after the system shuts off. An integral 5-micron filter will remove particulates. Calcium deposits that coat the inside of the pipe and reduce flow can be reduced by the use of rain, bottled or reverse osmosis water.

Fog can also be produced by a system using a high-speed fan with water channeled to the tip of the blades. The shearing action as the water exits the blades produces a fine fog. The fan distributes the fog above the crop canopy.

Water at household pressure, injected through a nozzle into a stream of compressed air, will also produce a fine fog. Each nozzle requires both a water and air supply. Different flow rates and droplet sizes can be achieved by adjusting the water and air pressure. Distribution can be through ducts, HAF fans or nozzles evenly spaced over the crop.

Fog systems frequently operate with a controller or computer that measures vapor pressure deficit (VPD). The difference between saturation water vapor pressure and ambient water vapor pressure is the VPD and represents the evapotranspirational demand of the surrounding atmosphere as well as the proximity to the dew point.

Although expensive to install, fog systems have worked well for cooling and can also be used for propagation.

Shama Jacob always knew he’d end up in the greenhouse business. His parents worked at Jolly Farmer — a grower of young and finished plants — since before he was born, “so it was natural I would follow,” he says.

Jacob started working at the greenhouse in seventh grade — planting flats, hand-mixing soil and sweeping under benches. In his mid-teens, he began working on the dairy farm that Jolly Farmer operates, where he milked cows, hauled hay and cleaned pens. Later, Jacob began assisting in the greenhouse by cleaning and helping growers spray fungicides and growth regulators.

In 1997, when Jacob was 19, Jolly Farmer reorganized and relocated from East Lempster, New Hampshire, to New Brunswick, Canada. The ownership structure shifted, and the Jacob family — along with several other employees — became shareholders.

Jacob helped build the new facility, which he especially enjoyed because he “got to run heavy equipment like the excavator, backhoe, dump truck and bulldozer.” One of the projects included installing a large wood boiler in January 2000.

After that was installed, Jacob began training to become a grower at age 22.

“Not many people want to be growers, because it’s hard work and takes a high level of dedication,” says Jacob, who turns 40 this year. “But it’s an opportunity for a lifetime of learning. This business keeps you humble. You never know it all, and just when you think you do, you learn something new.”

Team leader

In his current role as lead grower, Jacob manages five head growers. Each head grower oversees a different crop group, roughly divided between seed and vegetative crops, and by temperature blocks.

“My job is keeping us all together, orchestrating the labor for all the teams, coordinating team training and dealing with personnel issues,” Jacob says.

For example, if a member of the growing team calls in sick during February or March, which is peak season, Jacob might spend the day caring for that grower’s houses. Other times, he might divvy that grower’s work up among others, so he can focus on his own projects, like documenting trials for seed companies. He also helps growers spray three days a week, and constantly works to improve quality by adjusting growth regulator schedules and plant care instructions.

“My team and I are caring for 29 greenhouses during peak season,” Jacob says. “Plugs require an extremely high level of detail. The cells are very small, the concentrations are very high, and we as a company have no minimum order on our plugs or cuttings — so the numbers per group, per species, per size can be very small — so it’s intense.”

In April, Jacob’s focus expands to include finished crops. “The groups are bigger, the variety selection is smaller, and you have a larger container, which is more forgiving for moisture, so it’s less intense,” he says, even though his team still oversees at least 25 greenhouses through May, when finished production peaks.

Growth spurt

Last summer, Jolly Farmer added 10 more 300-foot greenhouses, bringing its total to 3.8 acres of covered production space on a 12-acre facility. As of press time, Jolly Farmer planned to add another six greenhouses this spring to help accommodate the growth they’ve seen, as soon as the ground thawed.

“We’ve struggled for years to fit in 10 acres, so we decided to expand,” Jacob says, citing steady year-over-year growth in plugs, cuttings and finished crops. “After we completed the expansion, we acquired a company, which completely filled the new expansion.”

Last October, Jolly Farmer acquired Sweet Valley Herbs from a nearby gourmet chef and his wife who started growing herbs in 1997 to supply local restaurants. The acquisition added a lineup of more than 100 varieties of herbs to Jolly Farmer’s production, which already included a few potted herbs and patio vegetables.

Family support

Jacob’s parents and several other family members are also involved in the business. His dad does programming, and his mom handles mailing for the company’s 3,500 customers. His sister does payroll, and his brother is vice president of Jolly Farmer’s transport division, operating a fleet of about 20 trucks that cover every province in Canada and every state in the U.S. except Nevada. Two of his cousins are head growers, and another works in maintenance.

With 300 employees at peak season (including a growing staff of 27), Jolly Farmer celebrated its 50th anniversary last year. Because of the close-knit culture there, Jacob considers the whole team his extended family.

“As a team leader, one of my challenges is balancing the need for 24/7 plant care with the needs of my team,” Jacob says. “The rewards of a close-knit, caring team are amazing, because people who really like to work with you will do their best for you day-to-day.”

Enorma is a new series of large Gazania rigens introduced by Hem Genetics in 2017, available in six colors and a formula mix. Our breeders selected for very large flower size, prolific flower production, and, instead of a grey tomentose leaf, we selected for a dark green, glossy leaf. That grey hairy leaf is a desert adaption to allow dew to condense on the hairs at night as a water source to drain down to the crown of the plant — for use as a bedding plant, that additional water at night can lead to crown rot. This motivated our breeders to select for faster draining of water away from the crown for better survivability in wetter areas.

Ideal for use in ground beds in sunny locations, it is also an outstanding winter annual in Florida, South Texas and the immediate Gulf Coastal area. It has good frost and light freeze tolerance and loves the cool nights and warm sunny days of the Deep South. It is also a plant often overlooked for use in mixed containers, because its flowers close at nighttime. Consider the fact that Gazanias add interest to containers because they provide motion — flowers opening in the mornings attract attention, and even the large closed flowers provide color and texture to mixed containers. Because Gazanias can withstand light frosts and short duration freezes, they can be utilized as both early and late season extenders.

For more: hemgenetics.com