The need for growing space reaches a peak in late spring before the start of the shipping season. What you need is some temporary growing space for a few weeks. Here are a few ideas that may help tide you over.
Easy-to-construct cold frames made from steel tubing can provide low-cost growing space. A single layer of poly will provide temperature and rain protection. A well-drained area with swales to remove the runoff is needed. On really cold nights, a layer of blanket material will provide protection. Rolling up the plastic to the ridge will provide ventilation and access for moving plants in and out.
Several greenhouse manufacturers make lean-to add-on sections that are attached to the sidewalls of gutter-connected greenhouses. Both straight and curved sections are available. Some growers have fabricated their own design out of pressure-treated wood or steel tubing. The frames need to be securely attached to the greenhouse wall and the ground to prevent wind damage. The attachment of the plastic along the greenhouse sidewall needs to be sealed tight to prevent heat loss and water infiltration. Using standard plastic fastening extrusions below the greenhouse gutter usually works well.
Heat for this new area can be provided from the adjacent heated greenhouse by rolling up the sidewall. During late spring, heat needs are less and the greenhouse heaters have the capacity to heat additional area. The temperature can be controlled by adjusting the height of the rolled-up plastic. Provisions for venting this add-on area are needed either with roll up sides or fans. For a few cents per square foot, you get additional growing space.
For growers with many hoophouses, using the normal 10- to 12-foot space between the houses for late spring production makes sense. During the winter, this area needs to be kept open to store the snow that slides off the houses. But once the snow danger has passed, this could be fitted with narrow hoophouses and covered with a single layer of plastic. Some growers use this area for holding cool season crops or hardening off plants before they are shipped. Temporary heat could be added with a portable vented heater. Ventilation is frequently limited to opening the endwalls or rolling up the sidewalls.
High tunnels are low-cost hoophouses without heat or mechanical ventilation. In addition to in-ground vegetable production, they are now being used for small fruit and cut-flower production. The use for spring production of annuals, perennials and potted plants is a natural extension of this type of structure. A covering of 6 mil poly and permanent endwalls of polycarbonate provide a low-maintenance growing area. Install large doors for easy access. Cost is usually less than $3 per square foot. Wider houses are less expensive and more labor and plant efficient.
Roll-out benches can provide additional growing space and an area for hardening off plants during late spring. Benches are supported on pipe rails and moved out through doors in the endwall of the greenhouse in the morning and pushed back in at night. A second layer of plants can be grown on the greenhouse floor. The system can be adapted to either hoophouses or gutter-connected ranges.
Rather than building additional greenhouses that increase your taxes and operating costs, consider adding some temporary growing space to fill in for the peak growing season. The payback for this space can be less than one year.
Bartok is a regular contributor to Greenhouse Management and an agricultural engineer and emeritus extension professor at the University of Connecticut. He is an author, consultant and a certified technical service provider doing greenhouse energy audits for USDA grant programs in New England.
Have a question? You can write John at firstname.lastname@example.org.
Meet the perp
Bio: Western flower thrips (Frankliniella occidentalis) are still the most destructive insect pest of greenhouse-grown horticultural crops, the reason being that western flower thrips cause both direct feeding damage to leaves and flowers, and indirect damage by vectoring viruses. This results in a very low tolerance for this insect pest.
Description: Western flower thrips are approximately 2.0 mm in length and light brown in color. The life cycle consists of an egg stage, two nymphal stages, two pupal stages, and an adult. Western flower thrips is extremely polyphagous, feeding on a wide-variety of greenhouse-grown horticultural crops including annuals, perennials, herbs, vegetables, and orchids. Both adults and nymphs feed on leaves and flowers.
Known locations: Commonly found residing in un-opened flower or terminal buds, which provide protection from either insecticides or natural enemies.
How they hurt plants: Western flower thrips cause direct plant damage by feeding on plant leaves and flowers with their piercing-sucking mouthparts. They do not feed in the phloem sieve tubes like aphids and whiteflies but instead feed on the mesophyll and epidermal cells of leaf tissues. Symptoms of feeding include leaf scarring, distorted growth, sunken tissues on leaf undersides, and deformed flowers. Leaves and flowers exhibit a characteristic “silvery” appearance due to the influx of air after the removal of plant fluids. Furthermore, black fecal deposits may be present on leaf undersides. Damage to plant leaves may also occur when females, using their sharp ovipositor, insert eggs into leaf tissue. Any wounds created during feeding or egg-laying may serve as entry sites for plant pathogens such as fungi.
Scouting for the perp
Monitoring or scouting is important to determine the numbers of western flower thrips present in the greenhouse throughout the growing season. Monitoring will determine seasonal trends in populations and assess the effectiveness of plant protection strategies. The primary technique used to monitor for western flower thrips adults is to place blue or yellow sticky cards just above the crop canopy. These cards should be counted weekly and the number of adults recorded. Visual inspections such as looking into open flowers, and/or shaking open flowers and leaves over a white sheet of paper are additional ways to determine the presence of adults and nymphs.
Sanitation is the best way to avoid problems with western flower thrips. Practices like removing weeds, old plant material and growing medium debris will help avoid or minimize problems with western flower thrips. It is also important to immediately remove heavily-infested plants and plant material debris from the greenhouse or place into containers with tight-sealing lids as western flower thrips adults may leave desiccating plant material and migrate onto the main crop. If economically feasible, installing insect (specifically thrips) screening over greenhouse openings such as vents and sidewalls will reduce adult populations from entering the greenhouse from outside.
Insecticides are still primary used to suppress western flower thrips populations. However, it is critical to rotate insecticides with different modes of action in order to avoid the potential for resistance developing. The same mode of action should be used within a generation, approximately two weeks, before using another insecticide with a different mode of action for the same time period. Natural enemies such as predatory mites (Neoseiulus cucumeris and Amblyseius swirskii) and bugs (Orius spp.) may be used to regulate western flower thrips populations; however, natural enemies must be released before high numbers of western flower thrips are present. The use of products that contain entomopathogenic (beneficial) fungi including Beauveria bassiana (BotaniGard) should also be considered. If used early in the crop production cycle these products may be effective in suppressing populations of western flower thrips.
Western flower thrips are one of the most damaging greenhouse insect pests. The best way to avoid infestations is to practice proper sanitation, including removing weeds, old material and growing medium debris.
Competition for water is heating up these days. Combine the boom in urban populations, expanded agriculture and industrial growth with extended drought and we’re left with demand that is outpacing supply. While southern and western parts of the U.S. have borne the brunt of water shortages in recent years, it won’t be long before water policy will have to change nationwide.
2011 offered Texas its driest year ever, with no drought relief in sight. Certain parts of the state have also been enforcing the tightest watering restrictions in the country. California is now suffering from severe water shortages and the state apparently has about one year left of groundwater reserves. Last summer, California enacted its first ever statewide water waste penalty. While water issues may seem reserved for those in the Southwest, other areas that aren’t traditionally dry have also experienced their share of drought. Areas across the Midwest, Northeast and Southeast are currently experienced abnormally dry periods as of the start of spring this year.
It’s also no secret that the availability of fresh water has become a clear and present danger for the green industry. With 40 to 60 percent of urban water usage attributed to landscape maintenance in warmer parts of the country, tight watering restrictions are already a reality for many homeowners. These restrictions combined with increasingly severe weather events are changing the way they buy plants and garden — or don’t.
Even if you’re receiving normal rainfall levels in your area, the impact on West Coast growers can have a cascade effect on your market region. The plant supply chain has already taken some significant hits in the last few years due to financial and economic factors. Water availability looks to be the next big challenge. Sustainability is no longer something to be considered just a trend. For many growers, it’s become a matter of survival.
While the issue and impact of drought on growers is multifaceted (and will require new growing methods and water-saving technology), focusing on drought-tolerant plant selections should be a top priority for breeders, growers, retailers and landscapers.
Most homeowners these days say they want landscapes and plants that are “low maintenance.” If you’re in drier parts of the country, that term is most certainly synonymous with “drought tolerance” or “low water use.” Over the last several years, the market has taken a decided shift when it comes to customers both accepting and seeking out drought-tolerant and low-water use plants. While the idea of drought-tolerant landscapes hasn’t always evoked images of lush beauty, customers are starting to learn that beauty can definitely be achieved using less water. This shift toward water conservation has customers assertively asking for water-wise plants and landscapes.
There has been a shift within the plant supply chain, according to Zac Tolbert, owner of Local Plant Source, Inc.
Local Plant Source, based in Austin, Texas, connects plant growers and buyers from coast to coast through an innovative online order management marketplace.
“We have been monitoring nursery inventory and upcoming project demand, and we are, in fact, finding more nurseries growing native and adapted plants. While these varieties are not explicitly drought tolerant, once established, these plants will survive and thrive without supplemental water," Tolbert says.
While Tolbert is seeing somewhat improved access to low-water use plants, he does offer up that supply isn’t yet meeting demand.
“However, just because these plants are becoming available from more growers, we are still finding that demand is outpacing the available supply. So while these indicators are encouraging, it proves that the market is still out of balance. The demand data that suppliers have access to, is still a lagging metric meaning they are constantly behind the trends and demand generated throughout the industry,” Tolbert says.
Smells like opportunity to me.
Certain plant species are naturally better able to tolerate drought and use water more efficiently than others. Their root systems enable them to take up water from deeper in the soil or they may sport smaller leaves or thick leaves with fine hairs. Succulents have gained huge popularity with residential homeowners, commercial property owners and municipalities for their ability to store extra water in their leaves and stems. Breeding using drought-tolerant species can help create less-thirsty hybrids.
Many breeding research programs are now treating drought tolerance as a primary focus. Colorado State University (CSU) is developing such a program. Graduate students and industry professionals can take their online course titled “Plant Breeding for Drought Tolerance” in fall of 2015. The next summer on-campus course will be held summer of 2016. CSU also held a Plant Breeding for Drought Tolerance Symposium last summer to provide connections between plant physiologists, agronomists and geneticists. The goal is to focus on drought-tolerance improvement through plant breeding and genetics. It’s a biennial symposium, so keep an eye out for the next one in 2016.
Hold the salt
With limited rainfall comes a larger dependence on groundwater for many communities. With groundwater often comes high salt levels in irrigation water. As municipalities rely more heavily on pumped groundwater, plants must tolerate higher salinity. Plants that are naturally salt tolerant have the ability to block salts from some of their cells. Improving both salt tolerance, primarily from irrigation water, and drought tolerance may be a congruent effort for some breeders. However, drought and salt tolerance don’t necessarily occur hand-in-hand in nature. Species that are drought tolerant aren’t necessarily salt tolerant and vice versa.
Which tech is best?
When it comes to breeding, the issues of drought and salt tolerance are complex and it’s expressed differently in ornamental versus food crops. For example, a plant that’s bred to be more drought tolerant may actually grow more slowly with reduced yields. That may be fine when it comes to ornamental landscape plants, but that strategy is counterproductive when it comes to food crops. Differentiating between drought tolerance and water use efficiency is tricky when it comes to genetic modification.
Currently, traditional breeding methods utilizing cross-hybridization have been more successful at achieving improved drought tolerance than gene modification. But scientists feel it’s only a matter of time before gene splicing technology catches up or at least augments traditional breeding methods when it comes to drought tolerance; or more importantly, water efficiency.
While much drought and salt tolerance research has focused heavily on agricultural crops, there are some research programs focused on finding out which ornamental plants tolerate less water and higher salts in greenhouse production and the landscape. Texas A&M University is conducting such research at facilities in both El Paso and College Station. Be sure to check in with your local extension agent to find out what water-wise research is being conducted in your area.
Are you offering a good range of drought tolerant plants to your customers? If not, now’s the time to start modernizing your production list. Be sure to investigate which water-wise plants for your growing area still offer up the best aesthetic value. Customers want to save water, but they still want beautiful plants. Many local botanical gardens and arboreta promote drought tolerant plants suitable for their area; stay involved with their plant trialing programs. When evaluating new varieties on the market, take time to review their water needs and even breeding parentage. Make it easy for landscapers and retailers to buy your water-wise plants by grouping the line together on your availability lists.
It’s a known fact. A plant depends on sunlight for photosynthesis and proper growth. Greenhouse growers, however, have gotten around the need for constant sun by installing high pressure sodium and fluorescent bulbs in their operations. In some regions, supplemental light is no longer an option, but a necessity in today’s market to maximize daily light integral (the amount light received in a specific area in a day’s period) on shorter days.
And now, growers are turning to yet another alternative: Light-emitting diode (LED) lighting. Science shows that with LEDs, growers won’t sacrifice light intensity. Plus, they may actually control how a plant grows and in some instances, enable it to grow quicker through adjustments in spectrum.
LEDs aren’t new, but they’re on the rise, with LED grow light module markets forecast to reach $1.8 billion by 2021 (the module markets earned $395 million in 2014), according to a 2015 WinterGreen Research report. The research firm is also anticipating worldwide “rapid growth” as LEDs are quickly becoming more efficient.
To that end, we’ve gathered testimonies from growers and information from manufacturers and researchers to explain the benefits LEDs can provide, as well as their potential setbacks, to help you make a more informed decision if you’re considering implementing LEDs in your own operation.
Watt for watt
Depending on the wattage, LEDs are just as intense, if not more so, than their high pressure sodium (HPS) counterparts.
“Because LEDs are more efficient, if you were providing an equivalent wattage light, say a 600-Watt (W) LED light, compared to a 600W high pressure sodium (HPS) light, our LED fixture is going to be delivering about double the photosynthetic par output [the range of spectral light plants require for photosynthesis] of the high pressure sodium,” says Cammie McKenzie product engineer at Horti-Tek, a commercial LED manufacturer in Florida.
She provides an example: If a grower is going from a 1000W HPS light burning 1150 watts per hour to a 600W LED fixture that’s going to give them the same results of the 1000W HPS fixture, they’re reducing their energy bill by almost 50 percent — and using about a fourth of the heat.
Chris Fifo, technical service adviser at Swift Greenhouses in Gilman, Iowa, trialed Horti-Tek lights in December 2014 with 600 square feet of seedling perennials and herbs (288 plugs) to see how they measured up to his HPS lights.
“The fixtures were really nice because you can just wire them into whatever is existing, and it automatically senses whether you have 110 or 220 volts, and adjusts [itself], so there’s no need to adjust or change any wiring,” Fifo says.
The 300W LEDs gave Fifo comparable growth to his current 400W HPS fixtures, and his results showed that with LEDs, he achieved the same photosynthetic par levels, and there were no adverse effects of using them, he says.
Although Fifo says he’s not ready just yet to implement LEDs into his entire operation, he’s looking toward the future. “It’s a great technology that’s evolving so quickly, and I think eventually it will reach a point where it can be cost effective to switch over to LEDs,” he says.
Some have already found the switch financially beneficial.
Jarratt Tunstall, vice president of Barnes Greenhouses, needed a better plan for his 9,000-square-foot facility in Dunkirk, New York, where the daily light integral is much lower during the winter season. That’s why he approached LumiGrow, an LED light manufacturing company based in California, in 2012.
LumiGrow worked with Tunstall to trial seven LumiGrow installments with his begonias and rooting geraniums. The next season, he purchased 40 more and now uses them throughout his entire facility.
“The geraniums were a lot faster to root,” he says. “After cutting a geranium, you can start seeing physical roots through an oasis wedge in a matter of seven days. Before that, it was two weeks [for us].”
It’s a 28-percent productivity gain, according to a case study by LumiGrow about Tunstall’s trial.
Not only did Tunstall produce higher yields, but he received a utility-sponsored, energy-efficiency grant from the New York State Energy Research and Development Authority, which significantly reduces his energy bill.
The savings turned the decision “into a no-brainer,” he says.
Coverage and customization
Tests show that not only do LEDs yield the same intensity as HPS lights, but coverage areas are also comparable, so long as growers work with lighting manufacturers to design a light layout, according to George Chan, marketing director for LumiGrow.
“When we brought the product to market…one of the design considerations was to create something that would function as a direct replacement for high pressure sodium, so we wanted to make sure that the light coverage was more or less the same pattern of the legacy lamp reflectors,” Chan says.
McKenzie says Horti-Tek’s newest model, which she hopes to preview in July at Cultivate ’15 in Columbus, Ohio will provide twice the intensity of traditional HPS lights.
There’s always room for improvement, Chan says, but LumiGrow is working to solve the myths that LED coverage is not equal to HPS lights. By conducting questionnaires and site visits, manufacturers can work with growers to cater to what they need on an individual basis.
The calculator McKenzie created at Horti-Tek considers a number of factors to calculate return on investment, including the model of light the grower’s already using, the LED equivalent and cost for installation, whether for a new build or a retrofit.
“We factor in the bulb cost and how often the facility changes their bulbs based on the hours and use, and we look at the wattage. We then look for any rebates that exist, whether federal or local utility company rebates, and we factor those into our calculator. Then we factor how many lights per day are used on different months of the year, and all of that comes together to tell us how much energy was used that year based on that light usage,” she says.
The calculator can also help determine how many years it may take for the LED systems to pay themselves back compared to HID systems, and then the savings cost over time of owning the system.
“Typical ROI for most facilities is three to five years,” McKenzie says.
Chan also says that HPS bulbs need to be changed every 10,000 to 20,000 hours compared to LEDs bulbs that are rated for 50,000 or more hours.
The use of just two colors drives most of the positive results of using LED light.
“Plants utilize four colors primarily, two reds and two blues for photosynthesis. That’s the core of the light,” McKenzie says.
Red is the color considered to be most efficient for driving photosynthesis, according to Dr. Roberto Lopez, associate professor of horticulture at Purdue University. But when plants are grown with 100 percent red light, some crops can develop abnormally. Blue light, on the other hand, balances the spectrum of light, and plants grown under blue light can be smaller and more compact, a quality that’s favored in greenhouse production.
But an additional perk of blue light, as researchers like Lopez are finding, is that it induces anthocyanins, the red and purple pigments that can enhance colors of flowers and foliage and make them more visually appealing for consumers.
“That’s a key thing. Color is really important for consumers, not only impulse purchases, but the reason consumers love [a plant such as] Purple Fountain Grass is because it’s purple. And if they go to the garden center and they see a green plant with tints of purple, they’re not going to buy that plant. And the main reason those plants are not very green is that in the greenhouse, you’ve got low light intensities,” Lopez says.
“Plus, if they’re grown under glass, they [receive] very low UV light. UV light also stimulates anthocyanins as well as blue light. That’s why [with] using blue LEDs, we can stimulate those anthocyanins quickly and you get that nice, deep purple color.”
Red and blue ratios can also be adjusted to enhance growth for specific plants. It all depends on the grower's goals.
“[If growers] want to keep the plants short, make them grow tall, they want them stretched, they want them to flower sooner, flower later: We can control that entirely with the spectral ratios we put together for those plant groups,” McKenzie says.
Lopez’s latest study at Purdue University found that growth of bedding plant plugs can vary by adjusting red and blue light ratios. In their study, Lopez and his graduate student determined that plugs grown under supplemental lighting or sole-source lighting from LEDs were generally more compact, greener and had a higher root dry mass than those grown under high-pressure sodium lamps.
“In terms of the work we’ve done with the supplemental and sole-source lighting of young plants, primarily plugs, it can be very species-dependent,” Lopez says.
Not only can light be used to adjust plants’ density, color and length, but it can also affect taste.
A study published by LumiGrow in 2014 showed that manipulating blue light specifically can even adjust the taste in edibles. Depending on the treatment, sweet basil plants could taste spicier or more bitter with just an 8-percent adjustment.
The right brand
The number of LED options is increasing, so it can be daunting to choose the right manufacturer to fit growers’ specific needs. That’s why it’s good to shop around before making a decision.
“One thing I always tell growers is before you make a large investment, purchase LED arrays from several different companies and do small trials to compare plant growth and energy use,” Lopez says.
When choosing a company to trial from, find a reputable company with an experienced sales and technical staff, says Ron James, division manager at PARsource Greenhouse Lighting in Petaluma, California. Also, "Find a company that sells many types of lights so customers can find the proper light that fits their specific needs," he says.
"[Growers] will also want to look closely at the manufacturer’s warranty, which should cover the LED light engine, driver and all fixture components,"says Lisa Jansen van Rensburg, marketing specialist for P.L. Light Systems, a lighting knowledge company in Ontario, Canada.
And sometimes, the best sources are peers. “Talk to other growers who have purchased LEDs and see what they have to say,” Lopez adds.
It would also be beneficial to look into local, state and federal options for rebates for switching.
“The price and the technology is at a place where the headline is no longer ‘LEDs are the future,’” Chan says. “It’s really that [LED] is the choice to make these days… We recommend before growers undertake either replacements or a new installation, that they conduct a thorough evaluation of various manufacturers and find a company they believe in and have confidence in.”
Check out a time-lapse video of Swift Greenhouses’ basil plants grown under LEDs in action at www.greenhousemag.com/media.
Mobile technology can increase efficiency, but how do you know if the investment is really worth it for your company?
I suggest the return on investment (ROI) model. Among others, ROI can be measured in terms of revenue increased, costs reduced and time saved. To calculate ROI, the benefit of an investment (the gain minus the cost) is divided by the cost of the investment. The result is expressed as a percentage or a ratio.
Assume you purchased a stock for $10. Two years later, you sell it for $14. Using the formula above, the ROI is 40 percent during two years, or a 20 percent annual return. Once you have an ROI calculated, you can use that number to compare this investment to another.
While the above is a simple example, ROI calculations can become complex. This is when careful analysis of the facts and projections come into play. Let’s look at an investment in technology — purchase mobile device hardware and software set-up for your crews and administration.
Here are our assumptions:
- Purchase price: $20,000, totally financed by the bank
- Financing: interest-only payments at 6 percent annual, paid monthly
- Insurance: $1,100 per year.
- Cost savings: $500 per day in labor and office costs
- Depreciation: Seven-year property straight line
- Combined federal and state tax rate: 40 percent
- Net profit: 15 percent
- Other assumptions: no inflation, no tax rate changes and zero maintenance costs.
So, according to my calculations (see table box), the annual return from this $20,000 investment in mobile hardware is more than 57 percent per year. The total ROI is more than 300 percent. Seems like a no-brainer, right?
We’ve calculated the tangible financial costs and benefits. But there are intangible benefits that can also be added to the mix. Intangible benefits may be that by using this technology, you can work fewer hours at the office and spend more time with your family. Perhaps using this hardware puts less stress on staff.
How do we quantify these intangibles? The time savings can be calculated assuming a labor rate assigned to how you value your free time. Employee satisfaction and stress reduction are even more difficult to quantify.
The questions don’t stop there. What if the investment gave a negative ROI in terms of cash, but it saved a lot of stress for your staff and office manager? And what if the technology ends up being a distraction to your production teams?
These are decisions that you as the owner must make. There may be times when the financial tangible costs outweigh the benefits but the investment still makes sense because the intangible benefits outweigh the intangible costs. In these cases the analysis is a little more subjective and may call for the inclusion of staff to help examine.
As we move to the future, investment in technology is necessary. But investing in it for investment sake alone is not a prudent strategy. Careful collection of all tangible and intangible costs and benefits must be laid out and a determination made if the benefits truly outweigh the costs.
Daniel is a New Jersey-based CPA. He runs Turfbooks, an accounting firm that serves landscapers. Email him at email@example.com