12 Pro Tips for Commercial Greenhouse Management February 1, 2017 – Posted in: Blog – Tags: greenhouse
Commercial greenhouses constitute a massive worldwide industry. Food and floral production steadily move from natural outdoor growing conditions to controlled indoor environments as technology advances and commercial greenhouse management knowledge evolves. In the past decade, the United States greenhouse industry has steadily grown from $3 billion in gross revenues to an estimated $4 billion in sales by 2020. This massive increase is driven by a need for higher indoor production due to limited labor, water and land.
Reducing overhead costs and responding to technological advancements, which require increasingly sophisticated knowledge about installation and daily operations, is a prime challenge for American commercial greenhouse managers. Producers in Mexico and other warm-climate countries that may have lower production costs — cultivating plants in low-technology conditions — present stiff competition to American greenhouses.
Today’s commercial greenhouse managers need to be on the leading edge of production and operations within their facilities. They understand that a commercial greenhouse is a food or flower factory containing perishable products that require constant attention and careful management. Operating a profitable and successful commercial greenhouse is a 24/7/365 commitment, even in the off-seasons.
Commercial greenhouses require a massive capital investment to maintain this intense form of agriculture. Returns are measured on a yield-per-square-foot basis rather than profits by the acre like outdoor farms. Inside, where crop failure can be caused by a mechanical malfunction, which can lead to quick-spreading disease, weather, is not a significant threat.
In a commercial greenhouse, artificial controls manage weather. Climate control is a prime responsibility of greenhouse managers, and this includes providing optimum lighting, heating, ventilation, insulation and greenhouse irrigation as well as ensuring the entire greenhouse operation is clean and free of invasive pests or fungal infestations that bring on mold — the killer of all indoor crops.
Greenhouse managers are more than mechanical and horticultural experts. Business can only prosper if crops produce profits, and this profitability involves all aspects of greenhouse management. Managers should be financially responsible for fiscal projections and quarterly budgets and be proactive in planning and scheduling crop harvesting. They should be compassionate human resource managers, astute marketers, skillful negotiators and even possess an ability to read the weather and make adjustments to artificial growing environments.
Well-roundedness in greenhouse management also requires an ability to economize the greenhouse operation’s efficiency and effectiveness. After labor, energy consumption is the largest overhead cost in greenhouse management. Other controllable expenses include preventing poor crop yield or total crop failure due to disease or pest contamination, which can happen if you neglect monitoring and maintaining a healthy artificial environment.
Effective greenhouse management involves energy efficiency and protecting crops, which reduces expenses. Tactics include proper greenhouse watering and irrigation, monitoring general plant health, integrating pest management, controlling mold and disease, maintaining cleanliness and ensuring the artificial environment is operating at peak performance.
Commercial greenhouse management includes continual education about the greenhouse industry. It also involves sourcing greenhouse tips and tricks to improve greenhouse energy conservation, climate control, greenhouse water systems and energy efficient greenhouse heating.
Energy Conservation and Efficiency
The biggest potential savings in commercial greenhouses is in addressing energy conservation and efficiency. Every greenhouse manager should prioritize producing greenhouse crops in environmentally friendly and energy efficient climates.
Heat, lights and air quality management are the main divisions that consume the bulk of commercial greenhouse energy consumption. There’s no escaping a fair amount of energy costs in greenhouse production, so most commercial greenhouse operations can benefit from addressing energy loss and replacing outdated, inefficient systems.
To help professional greenhouse managers achieve success, here are 12 greenhouse tips for energy conservation and efficiency in commercial greenhouse management.
1. Install Efficient Photoperiodic Lights for Long-Day Plants
Long-day plants prosper with nighttime lengths of less than 10 hours. Plants that thrive in long light conditions over 14 hours produce more yield in fewer days, yet they don’t require full light intensity for the entire daylight cycle or photoperiod. Reducing the amount of artificial lighting and replacing inefficient, incandescent light fixtures with more efficient photoperiodic lighting can have large paybacks in energy savings.
Incandescent lamps are best substituted with compact fluorescent lamps. CFLs consume one-quarter the amount of energy than incandescent lights and produce less heat during the photoperiod.
Cycling lighting is another energy-saving advantage for long-day plants where certain lights on a bank can be shut off or turned down to avoid unnecessary, full-strength lighting for the whole photoperiod. Consider using timers installing lights on moving boom tracks to distribute light across the pants at a varying rate.
Rotating reflectors are excellent energy savers for long-day plants. Reflectors amplify the existing amount of light and use less energy for the same return. The rotation further helps in uniform photoperiod light supply.
2. Use High-Intensity Lighting for Young Plants
Plant growth depends on photosynthesis, where they turn light into energy. Young plants are particularly responsive to an increase in photosynthetic daily light integral (DLI), which is the amount of photons delivered by the light source.
High-intensity lighting boosts the amount of photons offered to young plants, and it reduces energy consumption considerably. Light-emitting diode (LED), fluorescent (FL), high-pressure sodium (HPS) and metal halide (MH) high-intensity lights all increase the DLI at an energy consumption rate far less than conventional lighting.
It’s important to note that HPS and MH lights raise the temperature of the greenhouse, but they create greater photosynthesis of young plants, which more than offsets the energy consumption and heat management required.
Quite simply, young plants grown under high-intensity lights are healthier and grow faster than other plants, which creates a shorter growing period and less overall energy consumption.
3. Base Greenhouse Temperature Management on Crop Finish Date
All crops develop at a rate that fluctuates with temperature. Plants are hard-wired to respond to the natural heat cycles found in the four seasons. As temperature increases, plants naturally speed up growth. Conversely, as temperatures decrease, plants slow their growth and, at a certain coolness, they stop.
All plants have an optimum temperature at which they grow the fastest and offer the best returns. This temperature varies from plant to plant, and good greenhouse managers know a specific plant’s optimum temperature. Climates are the set around an anticipated finish date for a certain crop, and the optimum temperature is set and controlled from the start of the plant’s lifecycle to its finish.
If you grow according to the anticipated finish date and optimal temperature, you can minimize growth time.
4. Use Temperature Integration Strategies
Commercial greenhouses require more than internal air temperature and lighting controls. Water is an irreplaceable component in all greenhouse climate control systems, and regulating water temperature can be a source of considerable energy savings.
A method of greenhouse hydronic management calculates a target average temperature for a 24-hour period in the greenhouse environment, which includes the daytime high temperature and the nighttime low. This provides a set temperature where greenhouse energy loss occurs. You can set the irrigation water temperature at this point to balance the cooler temperature heat-loss. Water set at the target average temperature helps to regulate the overall greenhouse climate and compensates for heat loss at night and cools the plants during daytime’s heat gain.
5. Reduce Air Leakage
Loss of artificially heated air can be a major expense. Reduced air leakage offers large savings in greenhouse energy conservation. To achieve the benefits, consider the following tips:
- Pay attention to small gaps and holes in the greenhouse envelope
- Weatherstrip doors, windows and ventilation openings
- Seal the greenhouse foundation perimeter where the majority of air loss occurs
- Ensure automated devices for openings are properly adjusted and lubricated
- Shut off exhaust devices when not required
- Ensure all doors and windows close and fit properly
6. Insulate End and Side Walls
Proper commercial greenhouse design allows the site to take advantage of the sun’s natural pattern, which includes east-to-west travel and seasonal ray angles. As a result, greenhouses are designed with foundation and supporting walls located on the north side. They are also low to the ground on the east, south and west exposures.
Here’s a quick reminder of types of heat loss and gain that can occur in a commercial greenhouse:
- Radiation is heat transfer where temperature differences are exchanged by a line of sight. Warm surfaces always send heat rays to colder surfaces, which is why you feel warm standing by a radiator.
- Conduction is transferring heat through material. Energy directly flows from a hot surface to a cold surface, such as a pot on a stove.
- Convection occurs when heat is exchanged via fluid materials, such as air or water. As hot air passes through a metal duct or hot water flows through a plastic pipe, heat escapes by convection to surrounding mediums and surfaces.
Radiation, conduction and convection processes all occur inside and outside commercial greenhouses, which are often designed for maximum light transmission, not for maximum heat retention or exchange. Most commercial greenhouses utilize glazing or double-poly constructed walls that are amply insulated. Poorly insulated foundation or above-grade solid walls can cause heat loss and excessive energy waste.
Adding rigid foam or spray foam insulation to lower greenhouse walls can return enormous savings in unnecessary heat loss. Plastic bubble-wrap is another cost-saving method of insulating light-permeable greenhouse wall areas, especially north-facing regions that have little impact on light transmission.
7. Install Retractable Ceiling and Wall Curtains
Excessive solar gain can be as costly as air leakage and thermal heat transfer to the exterior. Energy expended in mechanically cooling commercial greenhouse interiors can be extremely costly in summer’s heat. An efficient and relatively inexpensive solution is shading the greenhouse interior from direct sunrays during high-intensity sun periods when cooling, and not light, is needed. Curtains also work to prevent heat loss during cool nights.
Installing retractable ceiling and wall curtains can be tricky to ensure smooth operation and prevent uneven shadow bands across live crops. Some commercial greenhouse growers report up to 30 percent savings in energy after installing retractable curtains.
Most retractable ceiling and wall curtains rely on electric, hydraulic or other mechanical devices to open and close. Advanced computer systems control some greenhouse systems, using solar-reading capabilities to read the ambient light and heat conditions and automatically compensate for solar gain and heat loss.
It is best to hire professional contractors to design and install advanced curtain systems.
8. Install Infrared Anti-Condensate Film
Battling excessive humidity is a constant process. As humidity levels reach maximum capacity, condensation naturally occurs and begins on the coldest surfaces. At night, this usually happens high in the greenhouse ceilings or on cold surfaces, such as metal fixtures and wall supports.
Polyethylene film coated with an anti-condensate material is readily available and comparatively inexpensive. This film allows water to bead and easily run off, which prevents dripping down onto plant leaves and causing damage from mold and insects.
Anti-condensate film coatings on glazing or other surfaces is a worthy greenhouse investment.
9. Properly Maintain Mechanical Equipment
All commercial greenhouses depend on some source of mechanical heating, cooling, water distribution and ventilation equipment. Greenhouse climate-control equipment requires routine maintenance, which is sometimes overlooked or delayed due to tight crop harvest schedules.
Regular maintenance schedules and properly trained technicians can keep heaters, pumps, air conditioners, ventilation systems and air movement handlers in peak condition. Preventive maintenance (PM) is crucial. Aside from knowledgeable workers taking care of maintenance tasks, proper PM includes adherence to strict schedules, systematic lists and attention to equipment manuals.
Unexpected and untimely breakdown of climate control equipment can be exceptionally costly in repair bills, labor consumption or potential crop loss or failure. Capital spent on developing and implementing routine, preventive maintenance will have returns greater than the investment.
10. Replace Outdated and Inefficient Climate Control Equipment
Commercial greenhouse operations face the same dilemma that most businesses experience. Technology is advancing at a rapid rate in the greenhouse industry, and older equipment — even if it is well kept — cannot compete with many new products and systems that offer superior energy efficiency.
Greenhouse managers must decide when to replace antiquated climate control equipment. Good managers take stock of their equipment, calculate its expected life span to determine the best time to purchase and install high-performance climate control equipment.
Sophisticated computer controls in new technology machines lead to lower labor costs and higher crop yields. Energy efficiency found in modern equipment can quickly pay for itself many times over. Understanding the rate of return and deciding on wise climate control investments is a major role in commercial greenhouse management.
11. Take Advantage of Product, Utility and Government Incentives
Commercial greenhouses are expensive operations to fund and operate. Take advantage of available discount, rebate and funding-incentive opportunities offered by suppliers and government authorities. Many utility companies also offer economic incentives, too. They offer energy-efficient consumption rebates for purchase and implementation of products like:
- Compact fluorescent lights (CFLs)
- LED (light emitting diode) lights
- IR polyethylene anti-condensate film
- Rigid and spray-foam insulation
- Retractable ceiling and wall curtains
- Automated control systems
- High-efficiency heaters, ventilators, air movers and dehumidifiers
Additionally, some federal, state and local authorities have loan and grant programs designed to assist commercial greenhouse operations that invest in energy efficiency.
12. Use Ventilation Systems for Maximum Climate Control
Proper ventilation is the key factor in achieving maximum climate control. Ventilation’s prime purpose is to control humidity inside the greenhouse, so plants can prosper at peak performance with minimal threat from insects and disease. Smaller greenhouse operations can function with passive ventilation, but large-scale commercial greenhouses depend on mechanical ventilation as their climate control center.
Humidity control is the single most important facet in an artificial climate application. It can also be one of the easiest factors to control and maintain. Keeping humidity to an optimum setting, temperature is more cost-effective to maintain and the threat of crop-robbing disease and insects is greatly reduced.
Humidity control starts with proper water management followed by regulating the greenhouse indoor temperature. The amount of water in the greenhouse atmosphere combined with the air temperature regulates the important factor of relative humidity, or the air’s ability to hold a certain amount of moisture relative to the existing temperature and pressure in the environment.
Relative humidity, or RH, is expressed as a percentage of moisture present in the air compared to the total amount of water the air is capable of retaining at that particular temperature. When the relative humidity reaches 100 percent, air is no longer capable of holding moisture, and it is released by way of condensation or rain.
In perspective, a comfortable relative humidity in a home environment is 55 percent with a room temperature set at 70 degrees Fahrenheit. Commercial greenhouse conditions tend to be more extreme than average household conditions, as most plants prefer more heat and humidity than humans do. The ideal commercial greenhouse humidity is approximately 85 percent with an artificial climate temperature also at approximately 85 degrees Fahrenheit. This 85/85 rule is generally the ideal commercial greenhouse setting.
Ventilation is the key to achieving and maintaining the 85/85 rule. Fortunately, raising humidity levels is almost never an issue in commercial greenhouses. Mechanical humidifiers are unheard of due to the massive amounts of water used in commercial greenhouses.
Ventilating to rid excessive water and humidity is the commercial greenhouse challenge. The best method to control humidity is the combined application of dehumidifiers and air movers. Moving air allows the moist, warm air inside the greenhouse to be exchanged with cool, drier air from the outside natural environment. Remaining air in the greenhouse goes through electric dehumidifiers that pull excess moisture and allow it to drain from the greenhouse.
Trust Aer Industries for All Your Greenhouse Equipment Needs
At Aer Industries, we offer the best selection of commercial greenhouse dehumidifiers and air movers. We handle leading brands of commercial dehumidifiers like B-Air© and BlueDri©. Commercial dehumidifiers can be simple machines that use basic conventional refrigerant or more complex dehumidifiers using LGR or low grain refrigerant.
Our line of commercial greenhouse air movers include industrial models from B-Air©, Blue-Dri© and Soleaire©. These manufacturers offer equipment that has been proven to provide quality and reliability in commercial settings. We offer a wide selection of commercial dehumidifiers and air movers to provide the best options for commercial greenhouse climate control.
Browse our section of dehumidifiers and air movers for commercial greenhouses and contact our industry experts. Aer Industries can help you control humidity and artificial greenhouse climates for healthier crops year round.