Powerful Poinsettias

Powerful Poinsettias

Producing poinsettias in today’s competitive market requires a great commitment of time and energy (and a bit of Tylenol). Taking steps that make your operation more sustainable can greatly increase your overall efficiency, reduce waste and boost your price per finished plant. Preventing nutrient imbalances that lead to deficiencies and toxicities can add a few extra steps at the start of the season, but you will reap the rewards, not to mention avoid the devastating damage a disease can spread throughout your entire greenhouse. Tracking the nutrient and disease status of your crop will improve your efficiency by saving you time on the end. Here are some ways crop tracking can improve your plant quality as well as overall sustainability.

An ounce of prevention is worth a pound of cure; it may be a cliché, but its message is worthwhile. As we come into another poinsettia season, we often are entering into the unknown. Yes, you have grown poinsettias for a number of years, but think back over the last few seasons. Each season throws something new at you. How do we know what to expect from 2008? The best bet is to know what you are starting with.

Establish A Baseline

Start Disease Free. Sampling of different cultivars for root pathogens at the rooted cutting stage is an excellent way to ensure that your cutting is disease free. One of the most common diseases of poinsettias is Pythium root rot and black leg. The cause of the disease is either Pythium aphanidermatum or Pythium ultimum. Disease often starts during rooting of the cuttings and can rapidly spread throughout the crop in ebb and flood systems (Figure 1). These fungi are soil-borne and spread via irrigation water, use of contaminated potting media, pots and rooted cuttings. Roots appear water-soaked are mushy and disintegrate when handled. A soft, watery rot anywhere on the cutting stem is also a sign of Pythium infection.

In the cutting phase, symptoms are easily confused with other cutting diseases, including Rhizoctonia stem rot and Erwinia blight. Erwinia is usually easy to distinguish since cuttings fall apart and completely collapse into a slimy mass within a couple of days. The characteristic rotten fishy odor is usually present when Erwinia has caused the disease. There are no reliable, clear-cut differences in symptoms from Rhizoctonia or Pythium. Since control strategies differ significantly, you must obtain a diagnosis to choose the correct path.

Water Quality. An initial water analysis at the beginning of your production cycle is crucial in producing a powerful poinsettia. At least two weeks prior to potting up the poinsettia crop, send in a water sample for analysis. Collect the sample from the source of water by running the water a while until fresh and then collecting a gallon or so in a large, clean plastic container. Dip the sample bottle into the water and cap it off. This method of collection eliminates trapping bubbles from a hose or faucet. Including any air might influence the analysis.

Water quality has a direct influence on the plant media and the availability of nutrients in that media. Since poinsettias are long-term crops, the grower must supply all necessary nutrients for optimum plant growth. Selection of fertilizer must be made with water quality, plant needs, stage of growth and interaction with growing medium in mind. Table 1 shows the water quality guidelines specific for poinsettia production.

Media. Poinsettia media must be well-drained and well-aerated. It must also hold enough water and plant nutrients to facilitate optimum plant growth. It should be pathogen free and physically stable for the duration of the crop. Un-composted organic components should be avoided as they may utilize available nitrogen and create a deficiency situation for the plant.

Controlling medium pH and EC depends on lime charge, media components, water quality, fertilizer selection, irrigation practices, growing environment and stage of plant growth. It is essential to monitor media pH and EC frequently with both in-house tests and through submission to a horticultural laboratory. In-house testing should be performed on each significant segment of the crop (dark versus light leaf plants, 6-inch versus 8-inch pots, trees versus mini pots, etc.) on a weekly basis. Monitor key crop segments every three weeks to verify in-house testing trends and also to understand the composition of the soluble salts that comprise the EC and affect pH. Sample more frequently if crop conditions or history indicates a need.

Two weeks after potting, media should be sent in for complete analysis. By this time, the lime and other media additives will have had time to react for a truer picture of the root zone chemistry compared to submitting an unused media sample. Unused media should be sampled only if subsequent sampling is done (two weeks later) to note the initial changes that occur.

Consistency in sampling is key to understanding and interpreting analysis results. Take a sample from the root zone area, excluding the top crust of media where salts are most likely to accumulate. Discussion abounds regarding exact technique of sampling media. Again, decide on a technique and be consistent about sampling at the same interval following irrigation with fertilizer. Taking the sample 24 to 48 hours after fertilization is recommended. (Figure 2)

When Problems Occur

Cultural effects and control of disease. There has been quite a bit of research done on controlling Pythium infection with focus on cultural conditions that promote Pythium root rot as a special focus. Disease has been found worse at pH above 5.5. Keeping the pH lower will help reduce severity. Disease increased 100 percent with a pH change from 4.5 to 6.8.

Disease severity increases as fertilizer application increases. Plants potted in peat-vermiculite appeared more sensitive to high soluble salts than those in other media. The moisture-holding capacity of the potting medium is also critical. Moisture-holding capacity above 70 percent seriously increased Pythium ultimum. Use of highly decomposed peat (dark) results in worse Pythium root rot (P. ultimum) compared to medium or light peat that is not greatly decomposed. 

Chemical And Biological Control. Rootshield (also called PlantShield–Trichoderma harzinanum) worked better than SoilGard (Gliocladium virens) but was less than Banrot (thiophanate methyl and etridiazole) when used as a drench at 12 oz./100 gal. Poinsettia cuttings in root cubes soaked in Subdue (metalaxyl) had slightly reduced root development but not as much as other fungicides tested. Trials on poinsettias with Pythium root rot showed that Heritage (azoxystrobin) and RootShield did not control the disease. Subdue was effective even under high disease pressure.

Common Nutrient Deficiencies

Molybdenum. Molybdenum (Mo) is needed by poinsettias in greater amounts than in other crops. It should be intentionally added on a CLF basis. Mild deficiency affects nitrogen utilization in the plant and progresses to cause yellowing in young leaves with upward rolling and edge burn. Leaf tissue may not expand properly in some cultivars due to distortion. Excessive amounts of Mo cause little or no plant damage.
Molybdenum may be difficult to detect at low levels in root media, but if a grower is consistently adding Mo, tissue analysis of most recently mature leaves may show very high levels (>15 ppm) as the element is readily taken up at proper pH levels.

Calcium. Calcium (Ca) is primarily moved into the plant via mass water flow rather than ionic root action. For this reason, deficiencies are not only a result of low concentration in root media, but can also result if environmental conditions restrict water flow through the plant (high humidity, stress, low light/temperature). Maintaining good air flow around plants via horizontal air flow enhances Ca uptake. Calcium recommendations vary, but most experts agree that supplying 100 to 150 ppm Ca through media and fertilizer application is sufficient. Alternating or co-injection of calcium nitrate, or 15-0-15 type fertilizers, with complete fertilizers is recommended. Or, N-P-K-Ca-Mg fertilizers like 15-5-15, 13-2-13 or 17-4-17 can be used.

Foliar Applications of Ca. Calcium is also absorbed through foliar application. Some growers use foliar applications of calcium nitrate or calcium chloride at between 300 and 400 ppm Ca on a weekly basis beginning when new breaks are in active growth phase and environmental conditions restrict uptake via the roots. Many growers begin foliar applications of Ca on a weekly basis at first sign of bract color. This is done to prevent bract edge necrosis.

Taking preventative steps to avoid nutrient imbalances and the devastating effects of disease will lead to a strong and successful poinsettia crop. Early analysis by an established horticultural nutrient or diagnostic lab gives you the information to be confident that you are starting to build yourself a high-quality crop of powerful poinsettias.

Leave a Reply

More From Blooming Potted Plants...

April 20, 2018

California Dreaming Takes on a Whole New Meaning at CAST 2018

At California Spring Trials 2018, the Greenhouse Grower team witnessed the revitalization of a company, plus some awesome merchandising displays, and efforts toward automation.

Read More

April 19, 2018

California Spring Trials 2018: New Intros from Syngenta Flowers, Hishtil, Jaldety, Cohen Propagators, Bailey Nurseries, and More

Check out the newest 2018 plant introductions from Syngenta Flowers, Hishtil, Jaldety, Cohen Propagators, Nir Nursery, Bailey Nurseries, and Sunset Western/Southern Living Plants.

Read More

April 19, 2018

CAST 2018: Dr. A’s Favorites From Syngenta Flowers, Bailey Nurseries, and More

From an exciting perennial to a new white begonia, Allan Armitage says these showstoppers deserve recognition.

Read More
Latest Stories

January 30, 2018

Grow High-Quality ‘Lyra’ and ‘Mirage&…

Syngenta Flowers' Technical Services Manager Karl Trellinger gives production recommendations for growing high-quality 'Lyra' and 'Mirage' poinsettias.

Read More

October 10, 2017

Coastal Callas Is a Dream Fulfilled for Founder Adrian …

Adrian Espinoza and his family founded Rancho Espinoza Inc. and Coastal Callas in California seven years ago with a mission and purpose to provide consistent quality and reliable supply of calla lilies to the marketplace.

Read More

October 3, 2017

25 New Blooming Potted Plants for Luxury Sales

Consider these new blooming potted plant varieties that offer full blooms, unique foliage, and a touch of extravagance and easy maintenance for time-strapped customers who want to pamper themselves.

Read More
Calandiva kalanchoes (Dümmen Orange) Feature

August 28, 2017

Lifestyle Plants Are in Full Bloom for Consumers

The latest decorating trends indicate consumers want hassle-free, colorful plants with big flowers — and growers are finding unique ways to cash in on these luxury-item sales.

Read More
Cyclamen Allure

March 28, 2017

Blooming Potted Plants for 2018 From California Spring …

We asked breeders to give you a peek at some of the great blooming potted plants they’re introducing this year at California Spring Trials. These new varieties will show up on the retail market in 2018.

Read More
Poinsettia 'Christmas Joy Marble'

February 20, 2017

5 New Varieties Shaking Up the Poinsettia Tradition

With poinsettias trending toward non-traditional colors, growers may find new opportunities to spread sales beyond the winter holidays. Here are five of the newest euphorbia varieties to hit the market that may play a role in redefining the future of the poinsettia market.

Read More
Euphorbia 'Gold Rush'

February 8, 2017

5 Ways to Tie Poinsettias to Lifestyle Trends for Incre…

With poinsettia planning upon us, here are a few ideas to incorporate them into upcoming lifestyle and home décor trends to help increase sales.

Read More
santos flare

December 20, 2016

Ball Horticultural Expands Potted Plant Offerings With …

Ex-Plant, which specializes in potted plants, will become a part of Ball’s PanAmerican Seed division.

Read More

December 16, 2016

Please Take Greenhouse Grower’s 2016 Poinsettia S…

Are plant sales up or down compared to last year? How did Black Friday set the tone for this season? What varieties and sizes were your best sellers? Did you try anything new this year to appeal to younger consumer demographics? We tackle all of these questions and more to help you understand the trends in Greenhouse Grower's 2016 Poinsettia Survey.

Read More

December 13, 2016

Dümmen Orange Shares Trends And Season-Extending Tips A…

As a purveyor of a wide collection of poinsettia and potted plant genetics, Dümmen Orange offered attendees a look at current trends – and a glimpse into the future – at its annual event in Columbus, OH.

Read More
Streptocarpus Ladyslippers Grape Ice (Green Fuse Botanicals)

September 27, 2016

9 New Blooming Potted Plants To Jazz Up The Home And Ga…

Blooming potted plants are the ideal gift for anyone, from a homesick college student to a spouse in need of some cheering up. Check out nine these new introductions hitting the retail market in 2017.

Read More
Eucomis arrangement from Golden State Bulb

August 19, 2016

What’s New With Blooming Potted Plants

From exotic orchids and lilies to flashy red cyclamen and jaunty gerberas, new blooming potted plants come in every shape, size, and color.

Read More
streptocarpus yellow blue eye, green fuse botanicals, march 2016

March 29, 2016

California Spring Trials: New Blooming Potted Plants Co…

Blooming potted plants are the gift that keeps on giving for consumers, and the growing opportunities in the gift plant market are opening up new possibilities for growers and retailers. Flower breeders exhibiting at the 2016 California Spring Trials (CAST) have several new blooming beauties of the potted plant variety to show off for the 2017 spring season. Before you head to California in a few weeks, take a look at the slideshow to get a preview. Which ones will you incorporate into production for 2017?     If you missed our annuals slideshows, don’t worry — you can check them out here. Because so many annuals are revealed at CAST, we had to build two slideshows — one for the Northern Region and one for the Central Region. Also, check out new perennials that will debut at the 2016 CAST. In the coming weeks, you can also see new woody ornamentals and edibles. Also, look […]

Read More

February 18, 2016

Poinsettia Survey Shows Strong Sales For Greenhouse Gro…

The year 2015 might have been one that many were glad to see in the rear view mirror, but for poinsettia growers, it was a good sales year — perhaps the strongest in quite a while. Compared to 2014, which was also widely deemed a success among growers for its seasonal cold at just the right time, good weather for shipping, and a good holiday spirit, the 2015 season was solid for a number of reasons. The weather, a rebounding economy, and increased demand all contributed to what growers said was a “very strong” sales season. “It was a strong year beginning to end due to great weather and quality product as the market demanded,” said Dan Chaney of Ivy Acres, in Greenhouse Grower’s 2015 Poinsettia Survey.     “Sales were strong. Demand was better than the previous two years,” said Larry Windham of Windham Greenhouses Inc. “Very good. The […]

Read More

February 10, 2016

Poinsettia Production On The Decline

Poinsettia production is on the decline in several of the top 15 poinsettia-producing states.

Read More

February 1, 2016

12 New Poinsettias For Holiday Growing

Poinsettias are still a consumer favorite during the holidays for home décor and gift giving. For greenhouse growers looking to get a jumpstart on purchasing young plants for the 2016 poinsettia growing season, there is no shortage of great varieties to choose from. Here are 12 new varieties to keep in mind for holiday product offerings.

Read More

January 26, 2016

Beekenkamp And Danziger Partner To Distribute Poinsetti…

Danziger is continuing to expand its portfolio of products to the U.S. market with the addition of poinsettia cuttings of Beekenkamp’s varieties.

Read More

January 24, 2016

Positive Consumer Experiences Help Advance The Orchid C…

HGTV HOME Plant Collection plans to expand its Fresh Style product line through a partnership with Green Circle Growers (Oberlin, Ohio), which will supply decorative orchids, tropical plants, and indoor garden combinations. Greenhouse Grower asked Maxwell Sherer about Green Circle's orchid program, the latest trends he’s seeing, and where he thinks orchid growing is headed in the future.

Read More