Produce High-Quality Rooted Cuttings

Fig. 1. Propagation bench with no shade cloth or shade cloth providing 31 percent, 68 percent or 86 percent shade. Supplemental light from high-pressure sodium lamps are used to create four different daily light integrals during root development.

Whether you are a propagation specialist or are rooting cuttings for your own in-house production, the goals of propagators are the same — to efficiently produce high-quality rooted cuttings. In order to meet the spring and early summer market dates for flowering bedding plants, cuttings are typically rooted in mid- to late-winter and early spring when the outdoor daily light integrals (DLIs) are at seasonally low levels. The DLI inside a greenhouse is often further reduced as a result of glazing material and interior structures, as well as hanging baskets suspended above benches to maximize production space.

Research has recently shed some light on the impact of light levels during propagation of New Guinea impatiens and petunias. However, the number of species and cultivars grown from cuttings is quite large and diverse. Therefore, we wanted to better understand the impact of DLI during propagation on growth and quality of several vegetatively propagated annual bedding plant species.

How the Study Was Conducted

Cuttings of Angelonia ‘AngelFace White,’ Argyranthemum ‘Madeira Cherry Red,’ Sutera ‘Abunda Giant White (bacopa),’ Diascia ‘Wink Coral,’ Lantana ‘Lucky Gold,’ Nemesia ‘Aromatica Royal,’ Osteospermum ‘Voltage Yellow,’ Scaevola ‘Blue Print’ and Verbena ‘Aztec Violet’ were stuck in 105-cell trays filled with a propagation substrate that was 50-percent soilless substrate and 50-percent coarse perlite. Cuttings were maintained in a propagation greenhouse with an air and substrate temperature set point of 73°F. During the first seven days of callusing, the average DLI was maintained at about 5 mol•m¯²•d¯¹.

After seven days, cuttings were placed in a greenhouse with high-pressure sodium lamps operating for 16 hours per day with either no shade cloth or shade cloth providing 31 percent, 68 percent or 86 percent shade (Fig. 1). We repeated the experiment two additional times to achieve a span of DLIs representing a range of greenhouse DLIs, from 1.2 (very low) to 12.3 mol•m¯²•d¯¹ (moderately high). Two weeks after being placed under the shade/lighting treatments, rooted cuttings were harvested. We measured stem length and caliper and washed the substrate off the roots so we could separate roots and shoots to record dry weights.

Supplemental Lighting Increased Both Shoot And Root Growth

Shoot dry weight (a measure of plant size) increased for all species as DLI increased during propagation, though species also varied in the magnitude of their response (Figs. 2 and 3). As DLI increased from 1.2 to 12.3 mol•m¯²•d¯¹, shoot dry weight of all species increased, from 50 percent (lantana) to 384 percent (diascia).

More importantly for cutting propagators, increasing DLI increased the root dry weight for all nine species. For example, increasing the DLI by 11 mol•m¯²•d¯¹ resulted in a 156 percent increase in root dry weight of verbena, while root dry weight of diascia increased by 1,137 percent. Additionally, the root:shoot dry weight ratio increased for all species as DLI during propagation increased. While the root:shoot ratio of verbena increased by 18 percent as DLI during propagation increased, the root:shoot ratio of osteospermum and scaevola increased by 329 percent and 419 percent, respectively. This means that although both shoot and root growth increased with DLI, cuttings allocated more growth into roots as opposed to shoots.

Increased DLI Has Variable Effect On Stem Length

While shoot and root growth increased with DLI for all species, there was no consistent trend in stem length in response to DLI during propagation. For example, as DLI during propagation increased from 1.2 to 12.3 mol•m¯²•d¯¹, the stem length of lantana and nemesia both increased by 20 percent while stem length of diascia increased by 76 percent.

Alternatively, stem length of argyranthemum, osteospermum and scaevola was unaffected by DLI during propagation. Similarly, stem caliper of bacopa, lantana and scaevola were unaffected by DLI, while stem caliper of angelonia, argyranthemum, diascia, nemesia, osteospermum and verbena increased with DLI during propagation by 11 percent (verbena) to 119 percent (diascia).

Measuring The Impact On Plant Quality

We often talk about plant quality, and several attributes contribute to our perception of this. It is generally desirable to have rooted cuttings and plugs with good root and shoot growth, a higher root:shoot ratio. They should be sturdy and not too leggy. Though we collected all of this data for cuttings, we wanted to integrate it to assess overall quality.

To do this, we used something we called the “quality index” (Fig. 4), a
value derived from an equation combining the total mass, root:shoot ratio and the ratio of stem caliper to stem length. The quality index increased differently for all species as DLI during propagation increased from 1.2 to 12.3 mol•m¯²•d¯¹, from 53 percent (lantana) to 960 percent (diascia).

Supplemental Lighting May Save Money  

In addition to producing high-quality rooted cuttings, lighting during propagation may actually save you money by reducing overall production time for rooted cuttings. How can adding supplemental light reduce energy costs? Let’s look at a few examples using Virtual Grower, a tool developed by the USDA-ARS to estimate energy consumption during greenhouse production. We will start by simulating propagation of angelonia in a 1-acre glass-glazed greenhouse in Indianapolis, Ind., in March.

Assuming an average greenhouse DLI of ~5 mol•m¯²•d¯¹, production will take about five weeks. Our day and night temperature set points will be 73°F and 70°F, respectively, for the first four weeks (callusing and rooting), followed by one week of 73°F days and 65°F nights (toning). It would cost approximately $1.02/ft² for the five-week period to finish angelonia cuttings if you are heating with propane. Now, if we provide 75 µmol•m¯²•d¯¹ (577 foot-candles) for 18 hours using 400-W HPS lamps this will provide ~5 mol•m¯²•d¯¹, bringing our total DLI up to approximately 10 mol•m¯²•d¯¹ during root development and toning.

The energy costs for operating the HPS lamps would be $0.03/ft²for the three-week lighting period. However, our heating costs are reduced, because under the higher DLI the cuttings finish one week earlier. Therefore, when the total energy cost for producing rooted angelonia cuttings with supplemental light ($0.86/ft²) is compared to no supplemental light ($1.02/ft²), we can realize a 15 percent savings.

Let’s look at another example using a species that has a stronger response to DLI during propagation  — argyranthemum. Using the same production facility and temperatures already described, we would have the same energy cost for heating during the five weeks of production — $1.02/ft². When we add the same supplemental light after a week of callusing, our cuttings would be finished in a total of three weeks. Our total energy costs for two weeks of supplemental lighting and three weeks of heating would be $0.77/ft², resulting in a 25 percent reduction in energy costs compared to argyranthemum cuttings rooted without supplemental light.

When interpreting these costs, it is important to know that energy costs will vary with greenhouse structures and glazing material, location and time of year. However, we think these examples are useful in seeing how lighting during propagation may affect your production costs.

Consider Whether Supplemental Lighting Will Work For You    
If you are currently rooting cuttings and looking for ways to improve both the quality of your liners and your efficiency in production, we encourage you to evaluate using supplemental light during propagation. A good starting point would be to begin monitoring the DLI in your propagation area to see how much light you are receiving during propagation.     GG

Leave a Reply

One comment on “Produce High-Quality Rooted Cuttings

  1. Buenas tardes, quiero agradecerles por poner a nuestra disposición este aclarador estudio y quisiera saber si han probado ustedes con esquejes de crisantemo y si es necesario dar luz suplementaria en las noches a el esqueje antes de que forme sus primeras raices. Muchas gracias Saul Correa

More From Structures & Equipment...
The-Capitol

July 7, 2015

Washington Gridlock Could Block Industry Research Funding

The latest standoff on Capitol Hill could have some implications for the floral industry, including future funding for floriculture and nursery research initiative activities, says Shawn McBurney, SAF’s senior director of government relations. “Republicans in the House and Senate are determined to work within the sequester-imposed limits for domestic spending in the federal budget, but Democrats have threatened to block any appropriations bills until Republicans agree to spend more money than that agreement allows,” McBurney says. “With both sides digging in, there could be an impact on budgets that affect programs and services important to the floral industry.” The back and forth over spending limits isn’t new, McBurney says. In 2013, then-Budget Committee Chairmen Paul Ryan (R-Wisc.) and Patty Murray (D-Wash.) negotiated an agreement that increased spending levels for defense and nondefense discretionary spending equally above the sequester level for two years, offset by fee increases and changes to mandatory […]

Read More
Medal of Excellence Award

July 6, 2015

Get To Know The 9 Variety Finalists For Editor’s Choice And Industry’s Choice Awards

Greenhouse Grower‘s Evening Of Excellence reception is rapidly approaching. Here, you can learn more about the varieties that are finalists for the Medal Of Excellence Editor’s Choice and Industry’s Choice Breeding Awards. Thank you to the 2015 sponsors of Greenhouse Grower‘s Medal Of Excellence Awards, Landmark Plastic, Nufarm and Stockosorb. Editor’s Choice Asclepias ‘Monarch Promise’ (Hort Couture) Basil ‘Balsamic Blooms’ (EuroAmerican Propagators) Celosia ‘Dragon’s Breath’ (Sakata Seed) Dianthus Jolt Series (PanAmerican Seed) Salvia Grandstand Series (Green Fuse Botanicals) Scabiosa ‘Kudos Pink’ (Hishtil Nurseries) Industry’s Choice Basil ‘Balsamic Blooms’ (EuroAmerican Propagators) Bidens BeeDance Series (Suntory Flowers) Celosia ‘Dragon’s Breath’ (Sakata Seed) Dianthus Jolt Series (PanAmerican Seed) Lobelia ‘Starship Deep Rose’ (Kieft Seed) Vinca Valiant Series (PanAmerican Seed)     Join us Monday, July 13 in Ballroom 2 at the Columbus Convention Center to find out which varieties will receive the coveted awards. The reception begins at 5:15 p.m. and the ceremony […]

Read More
crider-rd2-internal_Rough-Brothers_featured

July 1, 2015

Rough Brothers Is Acquired By Gibraltar Industries

RBI Solar Inc., Rough Brothers Manufacturing Inc. and affiliates have been acquired by Gibraltar Industries, a manufacturer and distributor of products for residential and industrial markets, for $130 million. Capitalizing on its 80 years of design-build experience and leadership as the largest greenhouse manufacturer in North America, Ohio-based RBI has established itself during the past five years as North America’s fastest-growing provider of photovoltaic (PV) solar racking solutions. The transaction will enable Gibraltar to leverage its expertise in structural metals manufacturing and materials sourcing to meet global demand for solar racking solutions. The company also announced that it anticipates its second-quarter 2015 financial results will be in line with its previous expectations. “Acquiring RBI is an important step in the transformation of Gibraltar into a company with a higher rate of growth and best-in-class financial metrics,” says Gibraltar CEO Frank Heard. “This acquisition directly aligns with key end markets and product platforms […]

Read More
Latest Stories
lighting feature

June 29, 2015

Customizing Crop Foliage Color With LEDs: Red Leaf Let…

In the first of a four-part series highlighting the multiple uses of light-emitting diodes (LEDs), researchers share how end-of-production supplemental lighting with LEDs enhances red leaf lettuce color prior to harvesting and shipping.

Read More

June 28, 2015

Keep Your Cool In The Greenhouse

Summer is in full swing, and that means growers need to worry about protecting plants and greenhouse employees from brutal temperatures. No sweat! These product manufacturers have offerings to help beat the heat.

Read More
Greenhouse Electrical System

June 23, 2015

Don’t Let Your Greenhouse Electrical System Come …

The size of a greenhouse operation is one of the biggest factors when determining the type of electrical system to install. Part 2 of "Don't Let Your Electrical System Come Up Short" covers locating electrical wires, meeting electrical load demands and environmental considerations.

Read More
Schaefer-fan

June 23, 2015

Schaefer Ventilation Opens Distribution Center In Atlan…

Schaefer Ventilation Equipment, a manufacturer of ventilation and thermal comfort products, has opened a new distribution center in Atlanta, Ga., to increase efficiency and provide faster services to dealers. Additionally, the company has added a new staff member to its agricultural and horticultural division to help expand markets in Latin America.

Read More

June 21, 2015

Greenhouse Project Moves Pavlodar (Kazakhstan) Closer T…

Despite regional challenges, greenhouse specialists Dalsem and automation supplier Hoogendoorn have collaborated on a greenhouse complex with the PTK company to bring Pavlodar (Kazakhstan) closer to self-sufficient, local food production.

Read More
HID Lighting System

June 18, 2015

Talking Shop: Using Lighting To Boost Beneficials

Peace Tree Farm was looking for a way to maintain beneficial insect populations through the winter. It found a potential solution through the use of rotating HID lighting.

Read More

June 17, 2015

Costa Farms Reduces Greenhouse Emissions With Solar Pow…

Costa Farms is seeking to make sustainability a top priority at its headquarters and two other buildings in Miami with the recent construction of new solar panels, which will replace 25 percent of the company's power usage with solar energy.

Read More
aquatrols

June 3, 2015

Aquatrols Renews Cooperative Research And Development A…

Aquatrols Corporation recently announced a new Cooperative Research and Development Agreement (CRADA) with Dr. Matt Madsen and the USDA Agricultural Research Service. The objective of the new CRADA is to further refine and evaluate surfactant seed coating technologies for use in wildfire rehabilitation, turf and pasture grasses, restoration species and other horticultural and agricultural systems. The three-year agreement renews a CRADA that Aquatrols first signed with the ARS in 2012. The original partnership has resulted in promising field and greenhouse trials, pending patents and initial steps toward commercialization of the surfactant seed coating technology. “We are very encouraged by the work that Dr. Madsen and his team have put together over the past three years,” says Aquatrols’ President and CEO Tracy Jarman. “This innovative technology has shown incredible potential with wide-ranging impacts in multiple industries. Aquatrols’ stated mission is to change the way the world grows and this technology has the […]

Read More
Greenhouse Electrical System

May 26, 2015

Don’t Let Your Greenhouse Electrical System Come …

Ensuring your greenhouse has enough electricity to operate all the equipment that is installed takes planning and consideration of an operation's needs. Part one of two articles on greenhouse electrical systems covers choosing an electrician, meeting immediate and future needs and planning for back-up power.

Read More

May 22, 2015

Nexus Greenhouses Is Optimistic For Expansion Into New …

Cheryl Longtin and Mike Porter, who own Nexus Corporation, say they were excited to attend the grand opening of Gotham Greens’ new structure atop the new Whole Foods grocery store in the Gowanus neighborhood in Brooklyn, N.Y., when it opened in December 2013. The project is just one example of some of the new and expanding markets that Nexus Corporation has expanded into over the past few years. Jeff Warschauer, vice president of sales for Nexus, says the company has enjoyed getting to know and working with the founders of Gotham Greens, Viraj Puri and Eric Haley, and Jennifer Nelkin Frymark, the chief agriculture officer, on their innovative approach to business. “They are very excited and work hard internally – just great people,” he says. “From our perspective, it’s great to see that excitement and vision. The employees there are happy and there’s no turnover; they’re only adding new people […]

Read More
Canadian Army Reserve training at GGS Structures.

April 30, 2015

GGS Structures Hosts Canadian Army Reserve Tactical Tra…

GGS Structures showed support for the Canadian military by opening up its fabric-covered Tasco Dome for tactical training to help soldiers prepare to fight in urban settings.

Read More
Growers are looking for low-cost options for temperature control, like circulating fans and exhaust fans.

April 10, 2015

New Ways To Give Growers Control Of The Greenhouse Envi…

From heating systems to circulation fans, manufacturing companies are finding new ways to help growers control the greenhouse environment, save on energy costs and streamline production.

Read More
Hendriks-Half-Open-Roof_GGS

March 26, 2015

10 Greenhouse Products For First-Rate Growing Environme…

From coverings to fork-lifts, greenhouse suppliers offer a variety of products to make growing easier. Check out the slideshow to learn more about these, plus several other products that can offer you value, versatility and durability.

Read More

March 16, 2015

Cozy Acres Greenhouses: Operating With Zero Emissions

With the help of federal funding, Cozy Acres Greenhouses was able to take a greener approach to its latest expansion, building a zero emissions greenhouse that operates year round.

Read More
interior view EDDG vent_energy efficiency codes

March 16, 2015

Stricter Energy Codes May Impact Your Ability To Expan…

Energy efficiency building codes that greenhouses are required to meet could soon be much more stringent, unless the National Greenhouse Manufacturers Association is successful in its bid to gain exceptions on greenhouse owners’ behalf.

Read More
NorthCreekGreenhouse_midmarch15

March 13, 2015

GGS Helps North Creek Nurseries Take Efficiency To A Ne…

North Creek Nurseries recently built a new GGS gutter connected poly greenhouse range with the intent of saving energy and implementing Lean Flow Practices. The aim was to help North Creek improve the quality of products and meet increased customer demand, while at the same time saving money on labor.

Read More
Polyarch Berns

March 12, 2015

Energy Audit Resources To Reduce Energy Costs In The Gr…

One way to reduce energy-related costs in the greenhouse is to conduct self-audits on a regular basis. These energy audits allow growers to identify potential savings by checking various production systems. To ensure your operation is running efficiently, check out these resources for help with your energy audit.

Read More
Retail Greenhouse

March 12, 2015

The Right Greenhouse For Any Grower

Selecting the right structure for your operation can be difficult. With so many options, it’s easy to feel overwhelmed. The good news is that greenhouse manufacturers are experienced in the art of matching customers with the ideal product. Here’s their advice for how to pick your next structure.

Read More