The Lowdown On Daffodils

The Lowdown On Daffodils

The growers at Longwood Gardens force tens of thousands of daffodils into flower every winter, providing a glimpse of what’s to come: spring. Now, I want to empower you with the essentials you need to grow equally impressive daffodils. 

Daffodil Basics

Daffodil bulbs can be obtained in different grades, as well as standard dry bulbs or pre-cooled bulbs. The standard grades of daffodils are: Double-Nose I (DN I), Double-Nose II (DN II) and round bulbs. DN I bulbs promise the most flowers, but flowers vary greatly among the different cultivars.
 
For forcing, I rely on DN I bulbs while smaller grades are an economic alternative for dry bulb sales. We are fortunate to have plenty of cooler space, so we can work with standard dry bulbs, which are more economical than pre-cooled bulbs.
 
 Juergen’s Top 4
Daffodils For Pot Production

‘Arctic Gold’ is a true image of a daffodil that does well in a pot. It is a yellow trumpet narcissus that is the quintessential icon of spring. In German, this type of daffodil is called “Osterglocke,” which translates into “Easter bells.”

‘Sir Winston Churchill’ is a cultivar of Division 4 or double-flowered daffodil. It is my favorite cultivar, perhaps, for its reliable strong show in a container. In addition, it is one of the cultivars that stand out because of its fragrance. Few other flowers produce such a strong and pleasing scent. This cultivar should be treated with a PGR to control plant height.

‘Tete-á-Tete’ is hard to beat in performance and customer recognition. It is a very compact cultivar that I don’t have to invest a lot of resources in to have a perfect crop. Small container sizes such as 5-inch bulb pans and even 4-inch pots work best for this showstopper. When grown right it is a cute little splash of spring ready to be picked up by consumers shopping in suppermarkets and garden centers early in the season. I have forced ‘Tete-á-Tete’ and other early cultivars for display in the first week of January.

‘Thalia,’ in my mind, is an illustration of grace and elegance. This daffodil is a perfect silver-white flowering cultivar that performs well in container production.

 
For forcing early in the season, coolers are indispensable. But for late-season growing, cold frames will do just fine in regions where temperatures approach freezing. Inconsistent cooling due to weather will result in uneven crops and poor flowering.
 
One of the most important decisions you’ll make is choosing a reliable supplier. It took me several years and some patience to find the right companies. Particularly challenging for the companies working with me is the fact that the Longwood Gardens’ forcing program consists of more than 100 daffodil cultivars for an average year. 
 
Frequently, displays consist of small numbers of pots. So I need only a few hundred bulbs for each cultivar. In these instances, I am below minimum order and my suppliers not only tolerate me, but they support our program. 
 
Many suppliers are set up to work with you to find the right selection of cultivars, so they are happy to provide you trial samples to promote their cultivars. Each year, I plant some extra pots of new cultivars. This gives me an opportunity to practice with these product lines and see how they perform and fit into my program.
 
Because commercial operations generally focus on fewer cultivars, they avoid some challenges I have experienced. Good suppliers will help you identify suitable cultivars as well as make sure you’re getting quality bulbs for a fair price. 
 
Bulb quality is also essential. You need to inspect each bulb crate upon arrival. Dispose of any soft or diseased bulbs. If something goes wrong during shipping or bulbs are infested with fusarium, tell your sales representative. You should be informing your supplier as soon as possible to get a refund or a substitute shipment. I have found combining orders and storing bulbs in a cooler will save on shipping costs. Bulbs can be stored for several weeks in a cooler with a set point of 63°F.

Potting Guidelines

A number of commercially available potting media have been suggested for growing daffodils. These media include Metromix 350 and Sunshine Mix 4. Longwood Gardens uses a custom bulb mix for the production of potted daffodils. This media is 55 percent peat moss, 35 percent coarse sand, 15 percent vermiculite and RootShield, a biological fungicide by BioWorks at a rate of 1.5 pounds per cubic yard of media.
 
Pulverized dolomite lime is added to adjust the pH to 6.0 to 6.5. I add sand to increase drainage as well as add substance and weight to the pots. The weight of the sand will help later in holding up plants in the pot, as well as anchoring bulbs into their place. At times, I notice bulbs pop out of pots when using peat light mixes.
 
Bulbs are best forced in bulb pans, which are available in sizes of 5, 6 and 8 inch. I select the size according to the different cultivars. Large cultivars should be planted into the large-sized 8-inch pan. More compact cultivars generally fit well into 6-inch bulb pans. Small and miniature daffodils should be planted into 5-inch pans.
 
On average, I fit five to seven bulbs per pot. The pots are filled with bulbs with little space between. Take care not to overcrowd containers. 

Vernalization & Forcing

Pots are watered in well after planting and placed in coolers for a cool treatment. Most daffodils require 15 to 17 weeks cooling. Some cultivars, such as ‘Early Sensation,’ are fine with just 12 weeks cooling. Pots should stay evenly moist. The quality of the crop can be affected negatively by uneven moisture during cooling. Crops should be checked at least weekly for watering and to determine their developmental stage. Cooler temperatures are reduced at certain intervals. The developmental stage governs the timing of decreasing temperatures. 
 
Stage 1: 48°F. Roots begin to show at drainage holes of the pots.
 
Stage 2: 41°F. The shoots start growing. Then, move pots before they are 1-inch tall.
 
Stage 3: 33°F. Maintain this temperature for the remainder of the cooling period.
 
Once the chilling requirement is completed, pots should be moved to a forcing compartment in your greenhouse. Choose a well-lit growing area (2,500 footcandles) and maintain a temperature range of 63°F to 68°F. Manipulating day and night temperatures can alter plant height. The bench time or forcing time varies greatly among the cultivars but ranges generally between 15 and 30 days. If you have time, you can grow plants at lower temperatures like 55ºF or 60ºF. 
 
Forcing at a lower temperature usually results in more compact and sturdier plants with stronger flowers. One has to weigh the prospect of better quality product with the cost of the bench space.
 
Often, people ask me when to plant bulbs and when to take them out of the cooler. This all depends on the display date, or for a commercial greenhouse operation, the ship date–and for a person trying to win a blue ribbon at the flower show, the date of the show. Determining the proper planting date is a basic equation and simple to calculate. It is best done using a spreadsheet. 
 
Subtract from the display date (DD) the time it takes to force (FD) the crop in the greenhouse and the time crops need to vernalize in coolers (VD). The result will be the potting date (PD). So again: PD = DD–(FB+VD).

Plant Health & Crop Quality

Provide good ventilation and air circulation to control humidity. This will be a good strategy to manage botrytis. However, fungicide application prior to shipment may be advisable. 
 
Over the last few years, I’ve had very little trouble with root born diseases. Currently, many growers still drench their crops with fungicides several times during vernalization–and even when forcing the crop in the greenhouse. I have had good results with adding RootShield to my potting media. I think by working with clean bulbs, keeping the coolers clean using RootShield, a lot of drenching could be eliminated. This would be good for the environment and save money on chemicals.
 
Plant height and compactness can be managed with DIF treatments and/or plant growth regulator (PGR) applications. A PGR labeled for use on daffodils is Florel Brand Ethephon, and I have had good results, especially with the larger-sized cultivars. 
 
Plants can be sprayed once or twice starting with the pencil stage. This is a developmental stage when the scape is still short and its form looks like a pencil. Also, make sure to manage your vernalization schedule well. Plant on time according to your delivery schedule. Over-chilling, as well as under-chilling, will affect the compactness of your crop. 
 
Keeping the pots too long in the cooler will likely result in lanky and floppy plants. Under-chilling can result in a more compact crop and, at times, become uneven in flowering. 

Harvest & Sale

Make sure you have arranged for swift distribution of your crop. Daffodils are highly affected by temperature. At a temperature range of 45ºF to 55ºF, daffodils exhibit a remarkable longevity of two and sometimes three weeks. At temperatures above 65ºF, flowers may last only a few days. 
 
Therefore, the shelf life of a crop is limited and flowering pots can be held for only a limited amount of time in coolers. Infrequently, I have held crops for about 14 days in a cooler with a set point of 32ºF. When holding crops longer in the cooler, plant quality will deteriorate. Please note that plants held for some time in the cooler have a shorter lifespan on display or on the shelf. They do not last nearly as long as plants that were never held in a cooler. 

Speed of distribution and temperature control during transportation to the sales shop are essential. It would even be worthwhile to have several potting dates with fewer pots per succession. So when delivering plants to the store, a smaller number is delivered on subsequent delivery dates, providing fresh merchandise over several weeks. 

Leave a Reply

More From Varieties...
Hendriks-Half-Open-Roof_GGS

March 26, 2015

10 Greenhouse Products For First-Rate Growing Environments

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
Rose rosette on Knockout rose, April 2012. Photo credit: Alan Windham, University of Tennessee

March 25, 2015

$58 Million In APHIS Farm Bill Funding Will Support Horticulture Priorities

Nearly $58 million as been allocated by the USDA's Animal and Plant Health Inspection Service (APHIS) to support the industry's Plant Pest and Disease Management and Disaster Prevention Program, under Farm Bill Section 10007. The program will support mitigation efforts for specialty crops, including providing research and other funding to address plant pest and disease priorities for the specialty crop industry, including floriculture and nursery crops.

Read More
AFE scholarship_Ryan Dickson

March 25, 2015

AFE Educational Grant And Scholarship Application Deadlines Approaching

Apply now for American Floral Endowment (AFE) scholarships or educational grants. Applications can be found online. For educational grants for 2015-2016, applications must be submitted no later than June 1. Scholarship applications are due May 1. AFE will award $40,000 in scholarships for 2015.

Read More
Latest Stories

March 25, 2015

13 New Shrubs You’ll Find At The 2015 California …

Woody ornamentals serve as the foundation of many great landscapes, but beyond their traditional uses, shrubs also add color, structure, texture and interest to small gardens and even containers. Check out this slideshow to see some of the newest introductions you’ll get to see at this year’s California Spring Trials.

Read More

March 23, 2015

Update To Armitage’s Greatest Perennials & Annuals …

A new update to the Greatest Perennials & Annuals app narrows the gap between consumers and grower-retailers, while providing more of Armitage’s top picks and growing advice for success with plants.

Read More
2014 Poinsettia Season Report

March 18, 2015

Download Greenhouse Grower’s 2014 Poinsettia Seas…

Poinsettia growers report a strong year in 2014, thanks to a few conditions. Seasonal cold at just the right time put consumers in a festive mood to buy early and often, and with no big snowstorms to hold up shipments and a reduction of supply available in the market, the season was strong from start to finish. Greenhouse Grower’s 2014 Poinsettia Survey received 143 responses from growers around the country. Here, you can download the complete results of the survey, by filling out the form.

Read More
Hydrangea 'Endless Summer BloomStruck' from Bailey Nurseries

March 17, 2015

Michael Dirr Slated To Address Attendees At Hydrangeas …

Dr. Michael Dirr to deliver the keynote address at Hydrangeas 2015 conference, hosted by the Cape Cod Hydrangea Society in partnership with Endless Summer Hydrangeas. The conference will take place at the historic Heritage Museums and Gardens in Sandwich, Mass.

Read More

March 17, 2015

16 New Blooming Potted Plants You’ll See At The 2…

Blooming potted plants are perfect gift items, and they put the finishing touch on any style of home decor. So when new varieties come on the market, growers and retailers alike take note of plants they know are going to make consumers happy. Check out the slideshow to see some of the new blooming potted plants making their debut to the trade this spring.

Read More
Salvia 'Ember's Wish'

March 11, 2015

Annual Salvias – Not Just Red Bedding Plants Anym…

Salvias are popular — and they need not all be the same. Here are a few you know well, and perhaps a few you do not. All are easy to grow and may be found through a broker or grower.

Read More
Dr Allan Armitage

March 11, 2015

Memoirs Of A Plantsman: Q & A With Allan Armitage

In light of the upcoming release of Dr. Allan Armitage's memoir, "It’s Not Just About the Hat — The Unlikely Journey of a Plantsman," Greenhouse Grower caught up with him for an in-depth Q & A about his newest work and what he’s planning next.

Read More
Lavandula-Superblue

March 10, 2015

How To Determine When To Buy Herbaceous Perennials In V…

Exposing herbaceous perennials to cold temperatures, also known as vernalization, can yield a range of effects, especially on flowering. Beth Engle of SHS Griffin covers whether vernalized liners or unvernalized plants make the best sense for your sales windows.

Read More

March 4, 2015

California Spring Trials Preview: 32 New Perennials For…

Perennials are hot and if this preview of the 2015 California Spring Trials is any indication, there are going to be some great new perennial introductions for 2016. We contacted the breeders who will be displaying their new varieties in California in April, and they gave us a sneak peek. Check out the slideshow to see some of the new perennials making their debut to the trade this spring.

Read More
Lavandula 'Meerlo' (Sunset Western Garden Collection)

March 3, 2015

Why You Will Still Grow Today’s Big Perennial 10 Years …

What will be the next big perennial? Breeders say it takes more than a splashy plant to distinguish itself in the market. Therefore, the question is not what will be the next big perennial, but rather what perennial performs well enough in the garden to have staying power in the market for years to come.

Read More
Heuch Pink Fizz_featured

March 2, 2015

Intergeneric Crosses Are A New Perennial Trend

Intergeneric crosses, oddities some botanists say are an impossibility, have made serious inroads in the perennial world.

Read More
Gaillardia x grandiflora 'Arizona Apricot'

February 25, 2015

National Garden Bureau Designates 2015 As Year Of The G…

Gaillardia, also known as the blanket flower, is a member of the sunflower family (Asteraceae) and a long-blooming pollinator plant. It is fitting that the National Garden Bureau has specified 2015 as The Year of the Gaillardia.

Read More

February 18, 2015

California Spring Trials Sneak Peek: New Annuals For 20…

If you're like us and you can't wait until the 2015 California Spring Trials to see some of the new genetics that will be hitting the market in 2016, never fear. We contacted the breeders who will be displaying their new varieties in California in April, and they gave us a sneak peek. Check out our slideshow to see some of the new annuals making their debut to the trade this spring.

Read More
Athena Brazil Salvia 'Brazilian Purple'

February 18, 2015

ForemostCo And Athena Brazil Unite To Supply Unrooted P…

ForemostCo, Inc. and Athena Brazil have forged a working relationship to support each other in the unrooted perennial cuttings market for North America. The partnership, geared toward accommodating increasing demand for unrooted perennial cuttings in North America, adds diversity to a recently consolidated market.

Read More

February 17, 2015

Poinsettias Had Their Best Year In Many In 2014

Poinsettia growers report a strong year in 2014, thanks to a few conditions. Growers were encouraged by high plant quality, enthusiastic shoppers and a stronger, less saturated market for poinsettias throughout the selling season. Seasonal cold at just the right time put consumers in a festive mood to buy early and often, and with no big snowstorms to hold up shipments and a reduction of supply available in the market, the season was strong from start to finish.

Read More
Geranium x cantabrigiense 'Biokovo'

February 17, 2015

Geranium Hybrid ‘Biokovo’ Dubbed 2015 Peren…

Geranium xcantabrigiense ‘Biokovo,' a naturally occurring hybrid of G. dalmaticum and G. macrorrhizum, is the Perennial Plant Association's top pick for 2015 Perennial of the Year. Learn why this tough, landscape geranium took home the prize.

Read More
Costa Farms' Season Premier 2015

February 4, 2015

Costa Farms’ 2015 Season Premier Reveals Newest V…

The annual Season Premier at Costa Farms in Miami, Fla., is the industry's very first peek at new varieties for debut the following year, even before the California Spring Trials, heralded widely as the jumping off point for new varieties. This year's event revealed breeders' best and brightest new varieties for 2016, shown in field trials, landscape trials and containers at Costa Farms tropical trial gardens. Plant breeders presented their new varieties to buyers and members of Lowe’s grower panel. Growers, brokers and other allied industry members, including Home Depot growers and buyers, were also able to peruse the grounds to see how the new varieties fared in the winter trials. Later this season, the hot and humid conditions at Costa’s summer trials will help identify the true performers.

Read More

January 28, 2015

All-America Selections Introduces Additional 2015 Winne…

All-America Selections has announced more 2015 AAS Winners, bringing the grand total of introductions for the 2015 gardening year to 25. The seven winners join the 12 announced last November and six announced last July. This year, AAS has had the most winners in one year since 1939.

Read More