Control Stem Length With Liner Dips

Control Stem Length With Liner Dips

As you are getting ready to place your early plug and liner orders before winter, you may be reflecting on the incredible variety of spring annuals you are growing in your greenhouse. One of the biggest challenges in bedding plant production is controlling unwanted stretch or stem elongation. But how can you effectively control stem elongation of so many different species in a single greenhouse or in a combination container?

There are several techniques growers may use to control stem elongation. For instance, a warmer night air temperature than day air temperature creates a negative DIF (DIF is day temperature minus night temperature), which has been shown to minimize stem elongation. However, the effectiveness of a negative DIF varies with species. With today’s high energy costs, it can be cost prohibitive.

Therefore, a more practical and economical tool is to treat each species with plant growth regulators (PGRs). Chemical PGRs are usually applied as foliar sprays to plants in packs or containers. However, some PGRs such as ancymidol (A-Rest, Abide), flurprimidol (Topflor), paclobutrazol (Bonzi, Piccolo, Paczol, Downsize, Florazol) and uniconazole (Concise, Sumagic) are taken up by roots and have growth-regulating activity when applied to the growing substrate. Growers may apply substrate drenches containing these PGRs, which often result in increased control and uniformity in curbing stretch.

Dipping trays of rooted liners and plugs into a PGR solution, or liner dip, is a newer method of efficiently applying root-absorbed PGRs that controls stem elongation after transplanting. The use of liner dips allows growers to efficiently apply the required PGRs to a large number of plants. It can also give growers the ability to treat individual plants with the PGR they need before combining them with other species or cultivars in a mixed container or basket.

While there is information about using liner dips on flowering annuals in both trade and scientific literature, little to no information is available for using liner dips with foliage annuals. We wanted to see if we could control stem length of several common foliage annuals that are used in combination planters and hanging baskets using PGR liner dips.

The Experiment

Trays of ‘Royal Tapestry’ alternanthera (Alternanthera dentata), ‘Silver Falls’ dichondra (Dichondra argentea), ‘Silver Mist’ helichrysum (Helichrysum petiolare), ‘Black Falls’ and ‘Marguerite’ sweet potato (Ipomoea batatas), ‘Goldilocks’ lysimachia (Lysimachia nummularia), ‘Emerald Lace’ plectranthus (Plectranthus oertendahlii) and ‘Variegata’ vinca (Vinca major) were received from C. Raker and Sons (Litchfield, Mich.) and Four Star Greenhouses (Carleton, Mich.). Liners were dipped into trays filled with solutions containing 8, 16 or 32 ppm ancymidol (Abide; Fine Americas); 4, 8 or 16 ppm flurprimidol (Topflor; SePRO); 4, 8 or 16 ppm paclobutrazol (Piccolo; Fine); 2, 4 or 8 ppm uniconazole (Concise; Fine); or deionized water (untreated control) for two minutes.

The day following chemical treatments, liners were planted in 4-inch round containers filled with a commercial soilless substrate composed of (by volume) 80 percent peat and 20 percent perlite. Plants were grown in a polyethylene-covered greenhouse under natural daylight with day and night temperature set points of 70°F and 67°F, respectively. Plants were fertilized with 200 ppm nitrogen from a balanced feed with each watering. Six weeks after treatments the length of the longest stem of each plant was recorded.

The Results

So what did we see? No PGR was effective in suppressing stem length of ‘Marguerite’ sweet potato (Figure 1) or ‘Silver Falls’ dichondra. Alternatively, every PGR at each concentration resulted in ‘Black Falls’ sweet potato plants with shorter stems compared to control plants (Figure 1, see slideshow below).

Only ‘Variegata’ vinca dipped in 32 ppm ancymidol had shorter stems than control plants (Figure 2, see slideshow below). ‘Emerald Lace’ plectranthus did not require any PGRs (Figure 3, see slideshow below). Stem length of ‘Silver Mist’ helichrysum was only shorter than control plants when treated with 16 or 8 ppm flurprimidol or uniconazole, respectively (Figures 3 and 4). All PGRs, at different concentrations, were effective for controlling stem length of alternanthera and lysimachia (Figures 3 and 4, see slideshow below).

In our experiment, we documented a variety of responses to different PGRs with the species we used. For example, we observed three general responses to PGR liner dips across species and cultivars used: 1) did not require chemical growth regulation (plectranthus); 2) were unaffected by most or all PGRs (dichondra, ‘Marguerite’ sweet potato, and vinca); or 3) were affected by each PGR at nearly every concentration (alternanthera, helichrysum, lysimachia and ‘Black Falls’ sweet potato).

Species and cultivar clearly interact with PGR active ingredients and concentration to affect stem length. Additionally, the variation between cultivars of the same species (i.e. sweet potato) underscore the importance of conducting in-house PGR trials to develop effective protocols for applying PGR liner dips to control stem length of herbaceous foliage annuals.

Using Liner Dips In Your Greenhouse

So what does this mean for you and your crop production? Liner dips can clearly be an effective PGR application strategy for aggressive foliage and flowering bedding plants. However, before dipping your liners or plugs into PGR solutions, get a clear idea of what you want out of your liner dips.

For instance, are you treating liners that will be planted individually in containers that will eventually be planted in a landscape, or are you treating liners that will be part of a mixed container planting? If you are treating plants that will eventually be planted in the landscape, you may be interested in a lower PGR concentration that will “hold” stem elongation until plants are placed in the landscape. Alternatively, for those plants that are going to be planted in a mixed container or basket, a higher PGR concentration that will slow or stop excessive elongation when the container is brought home by the consumer (Figure 5, see slideshow below).

Once you have identified what you want your dips to do for you, there are a few steps you can take to ensure success. First, identify the PGR you want to use and the desired concentration for that PGR. For a “hold” application, you’ll want to use concentrations that would be lower than those necessary for a “slow” or “stop” application.

Second, water your plugs and liners a day or so before you plan on applying the liner dips. This will ensure more uniform substrate moisture leading to more uniform uptake and subsequent control. If a plug tray or liner is too dry, too much PGR solution will be absorbed, resulting in too much suppression of growth. Alternatively, if a plug tray or liner is completely saturated, not enough PGR solution will be absorbed and you will not get enough control. Lastly, be sure to time your dip. Dipping plugs or liners in PGR solutions for 30 seconds to up to two minutes has been shown to be an appropriate range for application time. Treatments less than 30 seconds will not provide you with much control, while dips over two minutes may provide excessive control.

Takeaways

Next time you grow annuals from plugs or liners, consider using liner dips. They are an effective method for treating a wide variety of species and cultivars during a season in which variety in the greenhouse can be overwhelming. This research was conducted in the Northern U.S. during late spring. Rates will vary based on location and time of year.

Be sure to do some in-house trialing with the plant material and PGRs you use to identify which PGRs and concentrations work for the plants you grow.

 

Leave a Reply

More From Crop Inputs...

May 22, 2015

Nexus Greenhouses Is Optimistic For Expansion Into New Markets

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
Farwest2015

May 20, 2015

2015 Farwest Show Announces Second Annual Equipment Innovation Day

The second annual Equipment Innovation Day will be Tuesday, Aug. 25, prior to the 2015 Farwest show, which will be August 27-29 in Portland, Ore. Equipment Innovation Day, which was enthusiastically received in 2014, offers a real-time opportunity to see new heavy and automated nursery equipment in action. The demonstrations take place in manufacturing and nursery settings, adding value to the showcase. Attendees will be able to talk with participating manufacturers and learn first-hand from innovative growers who use the equipment in daily operations. The day-long event will be held at the main manufacturing plant of GK Machines, Inc., Donald, Ore. Further demonstrations of field equipment will take place at the nearby nursery of A&R Spada Farms, LLC. Bus travel to and from the event is planned, starting at and returning to the Oregon Convention Center. Attendees are welcome to provide their own travel to and from the site. Preregistration is required. The cost […]

Read More
Bee On Flower

May 20, 2015

White House Task Force Releases Pollinator Health Strategy

An interagency Pollinator Health Task Force commissioned by President Obama released its “Strategy to Promote the Health of Honey Bees and Other Pollinators” on May 19. The strategy, released in accordance with the Presidential Memorandum issued last June, is accompanied by a Pollinator Research Action Plan, which outlines needs and priority actions to better understand pollinator losses and improve pollinator health. The recommended actions will be supported by a coordination of existing federal research efforts and accompanied by a request to Congress for additional resources to respond to losses in pollinator populations. Pages 47 through 52 specifically address pesticides and pollinators. The report calls out plant production, native plants, mosquito control and all urban uses in its Pollinator Action Plan. RISE (Responsible Industry for a Sound Environment) says it supports the goals of improving pollinator health and habitat contained in the White House Pollinator Task Force’s release of its National […]

Read More
Latest Stories
Bee On Flower

May 20, 2015

White House Task Force Releases Pollinator Health Strat…

An interagency Pollinator Health Task Force commissioned by President Obama released its “Strategy to Promote the Health of Honey Bees and Other Pollinators” on May 19. The strategy, released in accordance with the Presidential Memorandum issued last June, is accompanied by a Pollinator Research Action Plan, which outlines needs and priority actions to better understand pollinator losses and improve pollinator health. The recommended actions will be supported by a coordination of existing federal research efforts and accompanied by a request to Congress for additional resources to respond to losses in pollinator populations. Pages 47 through 52 specifically address pesticides and pollinators. The report calls out plant production, native plants, mosquito control and all urban uses in its Pollinator Action Plan. RISE (Responsible Industry for a Sound Environment) says it supports the goals of improving pollinator health and habitat contained in the White House Pollinator Task Force’s release of its National […]

Read More
r3bv2 disease

May 20, 2015

SAF And AmericanHort Ask Government To Take Ralstonia O…

The Society of American Florists (SAF) and AmericanHort want Ralstonia solanacearum, Race 3, Biovar 2 (R3Bv2) taken off a list of animal and plant diseases that the federal government has determined could be misused as terrorist weapons. SAF and AmericanHort submitted formal comments together on the horticulture industry’s science-backed position on the matter. According to Lin Schmale, SAF’s senior director of government relations, extensive research has proven R3Bv2 does not belong on the government’s list of animal and plant diseases that can be misused as terrorist weapons. Every two years, USDA’s Animal and Plant Health Inspection Service (APHIS) requests a public review of the Select Agent list, asking for comments on whether plant or animal diseases should be taken off the current list or added to it. In the floral industry, R3Bv2 can have a devastating impact on geranium (pelargonium) crops, Schmale says, and both the potato and tomato industries also could be adversely affected by introduction […]

Read More
Two-spotted spider mites, adults and eggs

May 18, 2015

Beware Of Spider Mites In Bougainvillea And Mandevilla …

Greenhouse growers need to scout for spider mites on bougainvillea and mandevilla and use appropriate treatments that minimize pesticide resistance.

Read More
CrownBees_Blue-Orchard-Bee-Female_Artz

May 14, 2015

Pollinator Health 2015: What’s Next For Horticult…

The news on pollinators and neonicotinoids continues to fluctuate between good and bad. Research and outreach efforts backed by the Bee and Pollinator Stewardship Initiative help move the industry in a positive direction.

Read More
empress-intrinsic-brand-fungicide

May 13, 2015

BASF’s Empress Intrinsic Fungicide Is Approved Fo…

BASF’s Empress Intrinsic brand fungicide received supplemental labeling, providing California growers with an effective drench fungicide for disease control and plant health. The supplemental labeling is for use on herbaceous and woody plants in greenhouse, nursery container and field production in California. Empress Intrinsic fungicide provides protection against the four major root and crown disease pathogens: fusarium, phytophthora, pythium and rhizoctonia. Research shows Intrinsic fungicides control the broadest range of ornamental diseases while improving plant resilience to quality and reducing stresses that commonly occur during commercial production, handling and transportation. “More and more growers across the country are discovering the benefits of Empress Intrinisic brand fungicide treatments at propagation for rooted plugs, cuttings and seedlings, and in drench applications on transplants during the production cycle to protect against the major root diseases,“ says Joe Lara, senior product manager for BASF ornamentals. “A BASF fungicide program utilizing Pageant Intrinsic and Empress Intrinsic […]

Read More
Green Mum Basket

April 21, 2015

Growers Face Dilemma In Managing Plant Growth

Whether you’re applying plant growth regulators, manually pinching plants or using automated trimming, the most important thing is to find the right balance.

Read More

April 20, 2015

Three Michigan State University On-Demand Webinars Offe…

The first rule of effective insect and disease control for vegetables is to take action to prevent problems before they occur. But in order to do that, you need to have an effective pest and disease management strategy in place that incorporates best practices to ensure a successful outcome. Michigan State University offers three pest and disease management on-demand webinars that will get you started and keep you on the right track.

Read More

April 15, 2015

BASF’s Pageant Intrinsic Fungicide Registration A…

The state of California has approved the supplemental label registration of Pageant Intrinsic brand fungicide for disease control in the commercial production of greenhouse-grown tomatoes and tomato transplants for the home consumer market.

Read More
Egg card used for insect control in Parkway Garden’s retail area.

April 13, 2015

Biocontrols Use Requires Commitment

For some companies, a switch to biocontrols is an easy decision to make. Parkway Gardens of Ontario, Canada, began using biocontrols nine years ago after Erik Jacobsen, the company’s owner, wanted to expose Parkway, its customers and the environment to fewer pesticide products. “Many pesticides were increasingly ineffective, and in Canada, new product registration moves with glacial slowness,” Jacobsen says. “The labor cost of applying pesticides is much greater than using biocontrols.” In addition, it was also an opportunity to market the company’s eco-friendliness to a younger demographic, he says. In a Q & A with Greenhouse Grower, Jacobsen explains what biocontrols and methods have proved effective for Parkway Gardens Greenhouse Grower: In what types of greenhouse structures are you using biocontrols? Erik Jacobsen: Our greenhouses are all poly covered. About half the range is a Westbrook 14-foot at peak gutter-connected block, and the remaining half a mix of quonset-style […]

Read More

April 11, 2015

Lowe’s Announces Commitment To Phase Out Neonicotinoids…

Home improvement retailer Lowe’s companies announced April 9 that it has committed to eliminate neonicotinoid pesticides from its stores in a gradual phase-out over the next 48 months. In response, horticulture industry associations issued a statement that Lowe’s position is surprising, considering the most recent and positive reports on the state of honeybee health and recent peer reviewed research, and that this is an issue for which sound science must take priority.

Read More

April 9, 2015

Survey Snapshot Shows Biocontrols Mainstreaming

Have you incorporated biocontrols into your greenhouse operation? If so, you’ve got plenty of company. An anonymous online survey by Greenhouse Grower magazine in December 2014 of more than 156 ornamental plant and flower growers across the U.S. found 81 percent used biocontrols in 2014.

Read More

March 31, 2015

Manufacturers Are Taking Biologicals To The Next Level

Through acquisitions and new products, many crop protection companies are making firm commitments to the future of the biocontrols industry.

Read More
OxiPhos_BioSafe2

March 23, 2015

BioSafe Makes Label Changes To OxiPhos And ZeroTol 2.0

There have been some recent label changes made to the BioSafe Systems product OxiPhos, a systemic bactericide/fungicide that reduces downy mildew spores when tank mixed with ZeroTol 2.0.

Read More
Nufarm_logo

March 23, 2015

Nufarm Fungicides Now Registered For Use On Edible Crop…

Nufarm Americas announced label expansions for two of its fungicides that will provide more pest management options for the ornamental industry. The Cleary 3336 F and EG fungicides are now registered for use across a wider range of edible crops, including select greenhouse vegetables and transplants, herbs and backyard fruit.

Read More
ColeusDMLeafSporulation_Daughtrey

March 11, 2015

Research Gives Clues For Preventing Coleus Downy Mildew

Maintaining awareness of coleus downy mildew is more important than ever to safeguard these attractive plants for reliable garden performance.

Read More
Rose Rosette on Knockout rose, May 2013. Photo credit: Alan Windham, University of Tennessee

March 2, 2015

Rose Rosette Disease Fight Gets A Boost From Government…

In 2014, $4.6 million was awarded through the Farm Bill to tackle rose rosette disease, a devastating pathogen that affects one of the industry’s most important crops.

Read More
Fig 1 Leafy Gall On Leucanthemum Becky

March 2, 2015

How To Prevent Leafy Gall Before You Lose Plants

Leafy gall is a nasty disease that can go undetected until plant damage is done. Take these steps to protect your crops from infection.

Read More

February 17, 2015

A New Look At Biological Control: Can Plants Affect The…

The success of a biological control program depends on a number of factors including quality of natural enemies, timing of release, release rates and environmental conditions. However, what is typically not taken into consideration is how plants can affect the performance of natural enemies, including attack rate and searching ability. Biological control agents work hard to protect plants, but plants have ways to help themselves, too.

Read More