New Guinea impatiens are one of the most popular bedding plants. Their attractive foliage and large, colorful and plentiful flowers have made them an important annual crop for growers. While they are not the hardest crop to produce, they are not without their challenges. This article highlights the top “Do’s and Don’ts” for producing high-quality New Guinea impatiens.

Temperature

Compared to most herbaceous annuals, New Guinea impatiens are a warm-growing crop and are sensitive to cold temperatures. Their optimal temperature, the rate at which growth is fastest, is around 75° to 80° F, whereas temperatures below 60° F can slow down growth. Day temperatures between 68° and 75° should be targeted. When rooted cuttings are first transplanted, it is best to maintain night temperatures at or above 63° F to get them established. Once root systems have established and shoot growth resumes, night temperature can be lowered slightly but should still be maintained at or above 60° F.

Light

New Guinea impatiens are day-neutral plants and can flower under a range of day lengths. However, plant growth and flowering do respond to the daily light integral (DLI). A DLI of 4 mol·m–2·d–1 is required for a minimally acceptable crop. While good- and high-quality crops are grown under 6 to 8 mol·m–2·d–1 and 10 to 15 mol·m–2·d–1, respectively, avoid DLIs higher than this. Some of the newer varieties of New Guinea impatiens developed for full sun can be grown under higher DLIs, as these plants are more adapted to the stronger light intensity compared to traditional green- and bronze-leaf cultivars.

Water

It is best to grow them on the slightly drier side right after transplanting cuttings to let their root systems establish. Overwatering at this stage can slow roots down from developing. Once established, the substrate can be kept more moist than it normally would be. New Guinea impatiens growth responds positively to irrigation, and they are provided with as much water as they can take up, growth is pushed to the point of being excessive. Therefore, restricting excessive irrigation is one effective method of non-chemical growth control for this crop. However, be careful in moderating New Guinea impatiens substrate moisture. If they are repeatedly dried down too hard, plants will suffer and can collapse from repeated stress.

Nutrition

One key to finishing New Guinea impatiens is to avoid over-fertilizing plants during production. New Guinea impatiens are light-feeding plants, growing best with a substrate electrical conductivity (EC) between 1.0 and 2.5 mS/cm using the PourThru test. Providing too much fertilizer and allowing substrate EC to get too high can result in salt-stressed and damaged plants. Once cuttings are transplanted, fertilizer applications are not required for the first few weeks as plants establish, especially if the substrate has a starter charge. As plants establish and start growing, fertilizer can start to be applied. Using 100 to 200 ppm Nitrogen (N) at each irrigation, depending on irrigation leaching fraction, is sufficient. To avoid high salts, incorporating clear water irrigations and leaching with clear water is useful. In addition to managing EC, maintain substrate pH between 5.8 and 6.2. Too much fertilizer, or a pH below 5.8, may cause micronutrient toxicities.

Growth regulation

From propagation through finishing, New Guinea impatiens can be produced with little to no plant growth regulator (PGR) application. Cuttings root without any rooting hormone application. After planting, neither a mechanical pinch nor branching PGR is needed since modern cultivars are free-branching. New Guinea impatiens generally do not require growth regulators to control growth, as this can usually be accomplished through cultural factors such as managing irrigation. Should chemical growth regulation be required, paclobutrazol sprays (1 to 15 ppm) are recommended. For large containers with long crop times, ethephon sprays (up to 300 ppm) may be applied to abort flowers and buds and to keep plants vegetative as they are bulked up.

Pests and diseases

Tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV) are two particularly devastating viruses for New Guinea impatiens crops. Rigorously inspecting incoming cuttings and rooted liners for the necrotic lesions and concentric rings. Additionally, stay on top of thrips control, as they are vectors for TSWV and INSV and can transmit the viruses to otherwise healthy plants. Also keep an eye on root rots that may develop in New Guinea impatiens crops resulting from their water requirements.

To avoid high salts, incorporating clear water irrigations and leaching with clear water is useful.

Take-home

Well-grown New Guinea impatiens can be show-stopping plants on the bench. By providing adequate heat and light and adequate moisture, limiting excess fertilizer and drops in pH, and staying ahead of thrips and root rots, New Guinea impatiens can finish strong for strong spring sales.

The author (ccurrey@iastate.edu) is an Associate Professor in the Department of Horticulture at Iowa State University

As the owner or manager of a greenhouse, you know that things are about to get crazy. Before you know it, Mother’s Day will be here, crucial sales will need to be made and orders will need to be filled. Are you ready for the challenge?

At last month’s Garden Center Executive Summit, attendees were all in the same boat. They were getting ready for their Mother’s Day weekend rush, but before that hit, they took some time to learn, brainstorm and pick each other’s brains for ways to make their businesses better.

And let’s face it, whether you’re running a greenhouse, a garden center, a nursery or a combination of the three, spring is a tough time of year filled with many of the same challenges.

Many of the Executive Summit attendees were raring to go spend some time with other managers who all deal with the same problems, opportunities and challenges that come with running a business in the green industry. Gearing up for the spring season, the room was full of like-minded individuals who were all focused on the same goal.

The energy feeds off itself in those situations and it was inspiring to see people coming together to work ON their businesses instead of IN their businesses. Do you have a group of people either within your company or outside of it that makes you feel that way? Somewhere you can go to get inspired and focus on why you do what you do (and how you can do it better)?

When you’re so caught up in the day-to-day, it’s hard to find time to make things better. But when things get really hectic, it can be a great opportunity to pinpoint problems and zero in on inefficiencies.

And once this year’s busy season is over, take stock of what you’ve done well and what needs to be improved. Identify your big problem points or bottlenecks in production and write them down. If you don’t have time to address the issues now, at least you’ll remember them later in the year when you have a chance to reflect on the season.

Editor’s note: Stops are grouped into Central and Northern Trials. For more details and additional varieties, visit greenhousemag.com

For years, California Spring Trials has been one of the most anticipated industry events and most major breeders are still showing their newest plants at the event. In the following preview, get the lowdown on the new stops, the new varieties and more.

To see a more in-depth preview of the plants you can expect to see at each stop, be sure to visit us at greenhousemag.com.

We asked this year's participants to give us the lowdown on what's new and how you can make the most of your trip. On the following pages, you'll find tips from the pros help you have some fun in California, as well as a list of the stops on the tour.

And if you’re attending CAST 2020, be sure to let us know by dropping us a line at kspirgen@gie.net. We hope to see you there!

As you're making your way along the coast, don't forget to make a pit stop or two and have a little fun.

Don't look down. If you're a Hitchcock fan, don't miss the bell tower in San Juan Batista's old Spanish mission. It was featured in Vertigo! And if you head to the back of the mission, you can stand on the edge of the San Andreas fault.

Stop for sea lions. In Moss Landing, make a pit stop to see the sea lions near the docks in Moss Landing. While you're there, make a stop at Sea Harvest for the fresh seafood and observation lounge.

Harbor cruise. Ventura Harbor, home to the Channel Islands National Park headquarters, is a nice stop along the route with abundant shopping, dining and nightlife options.

Eat, drink and relax. You've got to eat, so keep these local favorite spots on your list. They all come highly recommended by CAST participants!

Grower's Pub in Salinas — With a historic atmosphere, this spot features a classic menu and the original 1940's bar. Try the Angus beef and local vintages.

Padaro Beach Grille in Carpinteria — Casual food and a beach atmosphere help this tour favorite live up to its tagline, 'Where food and paradise collide.'

Freedom Meat Lockers and Sausage Company in Freedom — These guys boast that their steaks are so good they don't need steak sauce.

Lilian's Italian Kitchen in Santa Cruz — The menu is inspired by the owners' grandmother so expect traditional Sicilian recipes combined with some other Italian influences.

Syngenta Flowers

Featuring ThinkPlants,

March 28 – April 1, 8:00 a.m. - 5:00 p.m.

2280 Hecker Pass Highway,

Gilroy, California, 95020

Contact: syngentameetings.us@one10marketing.com, (800) 427-1896

Danziger at Headstart Nursery

March 28 – April 1,

8:00 a.m. to 5:00 p.m.

4860 Monterey Road,

Gilroy, California, 95020

Contact: Dana Fernandez, dana-fer@danziger.co.il, (616) 899-2197

Benary and Benary+

March 28 – April 1,

8:00 a.m. to 4:30 p.m., 195 Paulsen Road

Watsonville, California, 95076

Contact: Jen Calhoun, jcalhoun@benary.com

Pacific Plug & Liner

Includes Berger, Flamingo Holland, Terra Nova Nurseries, Quality Cuttings Team, and branded plant collections Encore, Southern Living Plant Collection and Sunset Western Garden Collection

8:00 a.m. - 5:00 p.m.,

750 Casserly Road, Watsonville, California, 95076

Contact: April Herring-Murray, packtrials@ppandl.net, (831) 768-6300

Suncrest Nurseries

Featuring Cohen Nurseries, Hishtil Nurseries, Jaldety Nursery, Kamel Plastic Pots and Nir Nurseries

March 28 – April 1,

8:00 a.m. to 5:00 p.m.,

400 Casserly Road, Watsonville, California, 95076

Contact: Susan Liou, info@globalplantsource.com, (718) 715-6369

Speedling

Featuring Ameriseed, Hem Genetics, Lambert, Plant Source International and Vista Farms

March 28 – April 1,

8:00 a.m. to 5:00 p.m.

2640 San Juan Highway,

San Juan Bautista, California, 95045

Contact: Frank Yaun, fyaun@speedling.com, (813) 431-0615

American Takii

Featuring HilverdaFlorist,

March 28 – April 1,

8:00 a.m. to 5:00 p.m.

301 Natividad Road,

Salinas, California, 93906

Contact: Julia Paul, springtrials@takii.com, (831) 443-4901

Sakata Ornamentals

March 28 – April 1,

8:00 a.m. - 5:00 p.m.

103 Boronda Road,

Salinas, California, 93908

Contact: Jiana Escobar, jescobar@sakata.com

Floricultura

Featuring ABZ Seeds, Beekenkamp and Monrovia,

March 28 – 31,

8:00 a.m. - 4:30 p.m.

25425 Esperanza Road,

Salinas, California, 93908

Contact: Petra Dubbel, PDubbel@beekenkamp.nl, (612) 227-2072

Dümmen Orange at Avila Beach Resort

March 29 - 31,

8:00 a.m. – 4:00 p.m.

By appointment only

6464 Ana Bay Road,

Avila Beach, California, 93424,

Contact: CAST@dummenorange.com

Windmill Nursery

Featuring Dramm, J. Berry Nursery, Kientzler, Oasis Growth Solutions and Skagit Gardens

March 28 – 31,

8:00 a.m. – 5:00 p.m.

925 West Highway 246,

Buellton, California, 93427

Contact: Marc Englert, Marc@florep.com, (805) 850-8839

Seaside Gardens

Featuring PlantHaven, Suntory Flowers, Vivero International

Pop Up Exhibitors: Aris Green Leaf, Pacific Plug & Liner, Skagit Horticulture, Heritage Greenhouse Products, Southern Living Program, Sunset Program.

March 28 – 31,

7:30 a.m. – 5:30 p.m.

3700 Via Real, Carpinteria, California, 93013

Contact: new.plants@planthaven.com, (805) 569-9179

Ball Horticultural Company

Featuring Ball FloraPlant, Ball Ingenuity, Burpee, Darwin Perennials, Kieft Seed, PanAmerican Seed, Morel Diffusion, Selecta One and Wave Petunias

March 28 - 31,

8:00 a.m. to 4:30 p.m.

335 South Briggs Road, Santa Paula, California, 93060

Contact: Janessa Bender, springtrials@ballhort.com, (630) 588-3187

Green Fuse Botanicals

Includes One Floral, Schoneveld, Westhoff/PAC and TO Plastics

March 28 – April 1,

8:00 a.m. to 5:00 p.m.

15245 Telegraph Road, Santa Paula, California, 93060

Contact: Jann Turner, jturner@green-fuse.com, (805) 933-5599

Photo courtesy of Mary Lewis

As a PhD graduate research student at the University of Georgia, Mary Lewis primarily works with milkweed, a perennial native to the U.S. While she isn’t sure whether milkweed will be her focus forever, she does enjoy working with somewhat unknown plants, along with familiar plants, year in and year out.

Greenhouse Management: What appealed to you about continuing your academic career instead of pursuing a job at a grower or elsewhere in the industry?

Mary Lewis: For what I can tell, and what I’ve been told from all of my friends and coworkers in the industry, if I want to get the job I want [head breeder] and decide which way a program is going to go, that requires at least a master’s. That’s almost old-fashioned now and they are hiring more and more PhDs.

So I think I could get a job I want and slowly work my way up. But [if I did that] I’d never get exactly where I want to go.

GM: What have you learned from doing both internships at greenhouse operations and doing research in a university setting?

ML: I was fortunate, or unfortunate depending on how you look at it, that every time I took an internship I would leave saying, ‘That was fun, but that’s not really what I want to do.’ It was a wonderful opportunity to meet all of these different people in different parts of the industry, and I maintain those connections. But it also allowed me to narrow down what I exactly want to do so I’m not wandering around aimlessly. I knew what I wanted and what I wanted to do because I had been with PanAmerican Seed and did the whole assistant breeder job for four months and loved it. And from what I can tell, it will all be extremely useful. At the university level, my advisers have been great about picking classes for me that apply to the commercial industry and they have pushed me by getting me to go to conferences and events like CAST.

GM: How do you think your visibility will help during your future job search?

ML: I learned a lot from the AFE Vic & Margaret Ball internship program. I learned from that, that if you’re kind of in the system already — by working with named companies and they know you and like you — then your name gets around a whole lot easier. Some of it is you having to ask around and putting your name out there. But a lot of it I’ve been finding is that if you’ve done a good job and you’re doing a good job now, your name gets out and they know you before you even really come to them.