4. Clock Auction At Aalsmeer

5. Heating Pipes (Combined With Spacing Wires) At TheActively Growing Portion Of A Chrysanthemum Crop AtF. A. Duyvesteln in Naaldwijk.

)

6. Rolling Benches Are A Common Benching System All Over Holland.

4

night temperature of 60 - 65UF and a day temperature of65 - 75 F. They may be grown at cooler temperaturesbut the production time is longer. They will toleratetemperatures as low as 40 F.

Proper watering is important. Avoid excessivewatering. Streptocarpus can be grown slightly on the dryside. They can be adversely affected by cold water whichmay cause spotting of the leaves. For best results use roomtemperature water.

Streptocarpus are light feeders so there is little need|or much fertilizer (P. Larson, 1978). Afertilizer such as20-20-20 can be used at 100 - 150 ppm nitrogen weekly.

Streptocarpus has the potential of being a very popularflower in the industry. This may be attributed to: ease ofpropagation, low fertilization requirements, resistance todisease, few pest problems, growth at lower light, toleranceto temperature and ultimately, consumer satisfaction. Thesefactors help reduce the cost of production, enhancingStreptocarpus1 desirability and popularity.

GARDEN CHRYSANTHEMUMS

Walter L. Harper, Assoc. Prof, of FloricultureDepartment of Plant ScienceThe University of Connecticut

October is the month of the Chrysanthemum,Chrysanthemum morifolium referred to by most gardenersas "The Mum". Chrysanthemum means "Golden Flower" from thetwo Greek words Chrysos (Golden) and Anthos (flower), whichsuggests that the original mums were yellow, orange orcombinations of these colors. The mum is closely related to|two other popular perennial garden flowers, ShaSta Daisy(Chrysanthemum x superbum) and Painted Daisy orPyrethrum (Chrysanthemum coccineum.) All are in theCompositae, or Daisy family.

The chrysanthemum, grown in the garden, is the sameplant grown in the greenhouse as a florists' cut flower andpotted plant. The difference is in the cultivars. Theselection of cultivars for the garden is based on growthhabit, flowering time and winter hardiness. Greenhousecultivars are selected for production schedules and market

i?.

quality. While greenhouse mums are now manipulated by ,adjusting the photoperiod (daylength) to flower any seasonof the year, most garden mums flower normally during themonths of August, September, and October.

Because the greenhouse and garden Mum are the sameplant a question commonly asked of florists is, can I plantmy greenhouse mum out in the garden after it flowers? InConnecticut at least, the answer should be no. The cultivarmay overwinter, but most greenhouse mums are selected from /)a group that will flower early in November. By that timemost places in Connecticut will have had a frost or freeze, wjkilling the flower buds. J

The timing of the first frost or freeze is of concernto gardeners even with the garden Mum cultivars. At Storrsthe average date of the first killing frost or freeze isOctober 8. It has occurred as early as September 21.Obviously, mum flowers can be protected from light frosts bycovering them on those nights, extending the floweringperiod into Indian Summer. However, it is more prudent toselect garden Mum cultivars that start to flower in Augustand September to avoid the frustration of early frosts. Inthis way, frosts will occur toward the end of theirflowering period rather than at the beginning. Aware ofthis problem, plant breeders have beeen developing morecultivars that flower early. Perhaps September instead ofOctober should be called the "month of the Chrysanthemum".

Note that in this article we have referred to theChrysanthemum, Chrysanthemum morifolium as garden mumsinstead of hardy mums. The fact is that not all garden mumcultivars are hardy and some are only hardy during certainwinters. Somehow when they are called "Hardy Mums" there isan implied guarantee that they will always winter over.When they do not, the result can be customerdissatisfaction. To avoid this perceived problem, merelycall them "Garden Mums" to distinguish them from thegreenhouse mums. Once again plant breeders have beendeveloping chrysanthemum cultivars that are hardier than •others. Producers should thus grow and sell only thosecultivars that have proven to be most winter hardy in their \jNarea. i

Another way to encourage garden mums to winter over isthrough the use of winter mulches. A light covering withsalt marsh hay and/or evergreen branches applied at aboutthe time the ground freezes will help. This usually occursin late November or early December throughout most ofConnecticut. This type of mulch keeps the soil uniformlyfrozen. It prevents the heaving or thrusting of plants out

14

or space utilization scheme that permits growerspecialization (Figure 5). Local service organizationsprovide production equipment and supplies that are common toall growers, and boiler maintenance is done by serviceprofessionals. This enables a grower to give full attentionto growing a good crop. These practices have enabled theDutch to achieve their high level of labor and managementefficiency.

Labor efficiency is additionally achieved by keepinggreenhouse operations family size. The family is a strongeconomic work unit in many greenhouses in Holland today. In

Csmany of the greenhouses I visited, father, sons anddaughters worked wogether; in the case of Mr. Van Der Knappof De Lier, each of his four sons had a separate range ofhis own to manage.

Research at IMAG has evaluated the total efficiency ofevery worker's movement in the greenhouse. This researchhas paid off with many mechanized greenhouses having a laborcapacity of 30,000 square feet per worker. Amazingly, threeor four workers can run two acres or more of greenhouses.

Labor-saving developments have been almost totallyassociated with benching designs, conveyor systems andcarting systems. The most common benching system in 90percent of new pot plant greenhouses is the rolling bench(Figure 6). Rolling benches are preferred because theyrequire little change in labor management and allow 90percent of the greenhouse floor to be used — compared with65 percent with conventional benches.

The most automated Dutch bench system is the mobiletray concept, which provides for 95 percent floor spaceusage and essentially no aisles (Figure 7). An entire tray(for example 5 by 15 feet) is moved on either permanentconveyors or a conveyor train to and from the head house(Figure 8). The labor savings for mobile trays is aout 25percent, or three workers per acre rather than four.Capital costs are very high for this system and cropspecialization is essential to maximize the efficiency.

Further prospects for increasing crop yields,especially with roses, are believed to lie in soillessculture with rock wool. Rock wool is widely used invegetable growing in Holland, with approximately a quarterof the greenhouse vegetables grown this way. Use of rockwool has increased due to problems with methyl bromidefumigation of the soil. It was found that this chemicalleached into drain systems and canals, causing considerablepollution problems.

Researchers are also examining the possibilities ofgrowing chrysanthemums using nutrient film technique (NFT),

1) Wall to Wall Greenhousesin Naaldwijk: As Viewedfrom the Top of a Dike.

Most of the Cut Mum Cropsare Grown from Soil Blocks

Produced by SpecialistPropagators such asDe Mere! in De Lier.

3) National AgriculturalEngineering Institute(IMAG) at Wageningen,Eric Van Os of IMAG andCarl Salsedo Discuss

Movable Benches Utilizing90-95% of the Greenhouses,

of the soil which occurs with alternate freezing andthawing. This is a common cause of winter killing ofperennials.

Those mums most especially susceptible to various formsof winter injury or death are those that are purchased inflower and planted out in the fall. Much like the Pansy,Viola x wittrockiana in the spring, Mums can be sold inflower in the fall. The customer is obviously attractedto the flowers and can perhaps make a better visualselection for their garden at this time of the year.

The customer should, however, be advised to plant theMum out in the garden as soon as possible, rather thankeeping it in the house or on the patio. That is, ofcourse, if they want to attempt to overwinter the plant. Byplanting immediately the roots can get established while thesoil is still relatively warm. In the absence of rainfallthe plants should be watered thoroughly about once a week.When the ground starts to freeze a winter mulch should beapplied to these newly planted plants. Even then there isno guarantee that they will make it.

ant garden mums isfreezing weather ilae to the floristPlants can be grownter and spring andother perennials anening season. Some. The seed can be

and be sold from mi

The best time to piwhen danger of frost andMum cuttings are availabfrom February to July.size during the late winthe customer along withat the start of the gardnow offer mums from seed

bedding plants in March

in the springs about over,

and nurserymanto marketable

made available to

d bedding plantsseed companies

sown with other

d to late May.

A rather unique way to sell garden mums is to startappropriate cultivars from cuttings in late winter to flowerfor Mother's Day. When the danger of frost is over theseplants may be planted in the garden, cut back and allowed togrow again during the summer. They will then flower asecond time that fall in the garden, satisfying the customeronce again.

The mum is a versatile flower for the garden. TheCushion Mums are naturally low and compact and tend tobranch freely. The flower forms vary from the button likepompons, the daisy-like singles, the decoratives and thespoons to the large spiders. As in the greenhouse, thelatter must be disbudded to achieve the large single fllatter

The color

course yellasting flowers in the home.

ower.

range includes white, red, violet, orange and oflow. As a cut flower, mums are one of the longest

The Chrysanthemum, Chrysanthemum morifolium isnative to the Orient. It was grown in Chinese gardens

before 550 B.C. and is now the national flower of Japan.While it is not a low maintenance perennial, it has alwaysbeen a favorite in American gardens. Perhaps this isbecause the Mum signals the end of the gardening season inits own brilliant and colorful way.

Incidentally, does anyone know the national flower ofthe United States?

References

Aimone, Teresa. 1985, Cultural Notes. Grower Talks. 48(3):22-26.

Blazich, Frank and Joan. 1979. Streptocarpus, a new potplant. Nursery Business. 8/79:54-55.

Carey, Don. 1983. Bavarian Bells. Greenhouse Manager. 2(ll):70-75.

Freeman, Ralph. 1983. Streptocarpus. Minnesota StateFlorist Bulletin. 32(8):1.

Katzenberger, Ruth. 1976. Perfect Houseplants. Plantsalive. 4(2):34-35.

Kramer, Jack. 1980. Growing beautiful flowers indoors.St. Martins Press. N.Y., NY. 10010. 1980. p. 188.

Larson, Peter W. 1978. Streptocarpus Culture. TheMayflower. 215(9) :2-3.

Larson, Roy A. Floriculture. Academic Press. N.Y., NY.10003. 1980. p. 469.

Widmer, R. E. 1975. Streptocarpus (Cape Primrose) culture,Minn. State Florists' Bulletin. 8/75:3-5.

16

S

THE GLASS COUNTRY

by Carl A. Salsedo*

The Dutch greenhouse industry has grown out of a uniquecultural, geographical, industrial and environmentalsituation in Western Europe. Although Holland is a smallcountry, with 14.2 million people in a space about three

r times the size of Connecticut, it has an impressive 22,000acres of greenhouses (Figure 1). Winter light is extremelylow and much more limiting than any U.S. location, andheating requirements are similar to those of growersachieving \/ery high production of highlight crops such asroses, chrysanthemums and carnations.

How can they possibly do this while selling qualityflowers at some of the lowest prices in the world?

As part of a sabbatical leave from the University ofConnecticut Cooperative Extension Service, I studiedgreenhouse mechanization and space utilization as well asthe Dutch marketing system during July and August of 1984.I found that one answer to the above question has been theDutch growers' extensive use of machines and special growerservices to achieve high production at low prices (Figure

Labor-saving devices have been important forhorticultural production, with machinery research anddevelopment coming from the National AgriculturalEngineering Institute (IMAG) at Wageningen (Figure 3).Developments range from heated rolling benches for potplants to pot-placing machines, automatic transplanters forchrysanthemums and carnations and, most recently, amechanical greenhouse lettuce harvester.

Computers are used extensively for greenhouse climatecontrol, as well as for all aspects of marketing especiallyat the clock auction. Flowers at the auction are computeridentified and move quickly from grower to buyer. Thecomputer clock system performs banking, accounting,inventory and check-writing functions (Figure 4).

Space and TimeThe Dutch are masters of greenhouse mechanization and

space utilization. While there are many similarities inproduction equipment, each crop has some unique mechanical

* This article appeared in the Greenhouse Manager 5/9/85without pictures. This is the complete paper.