The Effect of Controlled Soiltemperatures on Growth & Cropping Characteristics of Three Typesby T.J. Blomand B.D. Piotl, Horticultural Research Institute of Ontario, Vine/andStation, Ontario L0R2E0
Introduction
Alstroemeria 198545
The interest in the production ofAlstroemerias has increased with Ontario growers in the last few years. Theweaker demand for locally grownchrysanthemums in combination withexcellent market opportunities forgreenhouse Alstroemerias are the mainreasons for this.
With the completion of newgreenhouses at H.R.I.O. it was decided,with the support of the Cecil DelworthFoundation, to examine the effect of soilheating/cooling on several Alstroemeriabreeding lines. Most research so far hasbeen focused on the effect of soil coolingon the 'Regina' type (Lin and Molnar,1983; Lin 1984; Healy and Wilkins,1982) while little or no information hasbeen published on some of the otherbreeding lines (such as 'Orchid', 'Carmen' or the 'Butterfly' types). The mainobjective of the study was to determinewhether year round control of the soiltemperature at about 16°C has abeneficial effect compared to a comparison house where the soil temperature was not controlled. The studywas initiated in the fall of 1984 and expected to last until fall 1986. This reportcontains a description of the experimental design and includes a summary of theresults after one-half year.
Materials and Methods
Four different cultivars are being usedfor this comparison from three differentsources. They are Red Sunset (source:van Staaveren, 'Carmen' type), Rosita(source: van Staaveren, 'Carmen' type),Rosario (source: Van Zanten, 'Butterfly' type), and Rio (source: Konst-Farrace, 'orchid' type). All varietieswere obtained through a plant lease-license agreement with these plantbreeder/propagators. The rhizomes of'Rio' and 'Rosario' were received bareroot and potted in 15 cm pots on September 20, 1984. These plants remainedin a greenhouse where a minimumheating temperature of 19/17°C (D/N)was maintained until the middle ofNovember. The other two cultivars werepropagated in the U.S. and werereceived on November 7, 1984 in 10 cmsquare pots. The latter plants were wellrooted. Planting took place in two glassgreenhouses (each about 50m2 in size) onNovember 20, 1984. New topsoil wasamended with aged manure and the soilwas steam pasteurized. Planting tookplace so that each bed of 6m2 had only
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one variety. Each bed was planted with36 plants with a final plant-spacing of2.9 plants per m2 0f greenhouse surfacearea. Rhizomes were planted ap-
Red Sunset (Carmen)
A Rosita (Carmen)
Rosario (Butterfly)
Rio (Orchid-type)
Month
proximately 15 cm deep. A total of fivesupport nets (15 cm square) per bed wereused to provide plant support. Eachvariety was planted in an identically
Alstroemeria 1985 (Soil Temperature Controlled)45-
located bed of the two adjacentgreenhouses, which were oriented N/S.The greenhouse air temperature wasmaintained at 16°C minimum for thefirst six weeks after which the temperature was decreased to 12/10°C(D/N) with ventilation at 20°C. Theheating temperature was maintainedthroughout the spring and summer except the ventilation temperature wasreduced to 15°C on February 28 andlater to 13°C to prevent any early heatbuildup during the warmer seasons.Liquid carbon dioxide was supplemented starting on February 13, 1985.
Polybutylene lines (19 mm) had beenburied in the soil at 50 cm depth and 45cm apart. Soil cooling or heating isprovided by allowing cold water (fromchilled water unit) or warm water (fromboiler), respectively to pass through thelines. Soil heating was started onFebruary 8, 1985 using manual control.Soil cooling was initiated on April 26,1985 and has run continuously. Insulation of the greenhouse floor surfacewas provided in three stages: thin layer(2cm) of polystyrene on May 9; then onJune 12 straw in the pathways (6 cm)with 1 cm of beads on the beds and onJuly 26 another 2 cm of polystyrenebeads on the beds. Soil temperature wasrecorded at different depths (8, 15 and22 cm) at four different locations in eachhouse by means of a datalogger.Although an automatic shading curtainwas employed, a layer of whitewash wasapplied on the roof on May 24. Supplemental lighting was applied betweenDecember 20 and May to obtain a totaldaylength of 16 hrs. by means of incandescent lights at 8 W/m2 installedcapacity. Watering and fertilization wasdone through the use of two growhosesper 1.20 m wide bed. From October -February there was one watering per 7-10 days. Between April and July thecrop was watered on the average everyfour days. The irrigation rate was
29-
Alstroemerias 1985 Soil and Air Temperatures
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WeeknumberFigure 3. Weekly average air and soil temperatures (or two houses.
generous at about 30 mm per watering.Fertilization took place based on regularsoil reports but during the summer theplants were fed 130 ppm N using 20-5-30on a continuous basis. Regular applications of phosphoric acid were applied to reduce the pH.
So far only three applications of snailbait and two applications of an aphicidehave been applied to control pests.
Results
The first flowers of Red Sunset andRio were harvested on March 26. Rosita
produced the first blooms 10 days later,while Rosario was 20 days later thanRio. Harvesting took place three timesper week by pulling the stems whichwere then graded according to theirquality. Three grades were used:Grade I: stemlength 80 cm and overwith four or more pedicels per cyme,
40 45
with each pedicel having at least twoflowers.
Grade II: stemlength 80 cm and overbut with 2-4 pedicels per cyme.Grade III: other than I or II.
There was generally no problem in attaining the 80 cm length except forRosario which were only marginallyshort. Therefore, the length requirementfor grade I and II was changed to 60 cmfor Rosario only. Rio, on the otherhand, was extremely tall (2.5 m) duringthe first flush. Red Sunset and Rosita
reached a height of 1.20 m in the beds.The production of the first year untilOctober is given in Figures 1 and 2.
There are two interesting observationsto make at this point:1. The control house had an overallhigher production (16%) for all varieties(no exceptions!) compared to the soil
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temperature controlled house. This is interesting, as the soil-cooled houseshowed a similar production for themonth of April and all the differenceswere shown during May-July, while thecooling did not have any effect on soiltemperature until week 18 (Figure 2). Allvarieties appear to have had two distinctflushes by the end of July, and havediminishing production from August toOctober.2. The highest percentages for grade#1 were obtained by Rio and Rosita.Red Sunset and Rosario had many grade#2 due to the lack of sufficient pedicelson the cyme (usually 3) or a lack ofsecondary or tertiary flowerbuds. Nodifference was found on the quality patterns among the two houses for thecultivars. This may indicate that thequality of the Alstroemeria is not influenced by the soil temperature butmore by the environment above the soillevel. During the month of July therewere many shoots predominately onRio, which had some of the primaryflower buds aborted (dried up).However, it is rare that all flower budsare aborted on each pedicel. In July,many blind shoots developed on thevariety Red Sunset. The stems of allvarieties were very brittle during Julywith Red Sunset showing the worst.
The results of the soil temperaturemanagement is shown in Figure 3 (nosoil temperature recording before week16). Although the soil temperature wasmeasured at three different depths (8, 15and 22 cm) it was considered that the 15cm depth was the most representative ofthe rhizome and therefore used in Figure3 (average of two locations). In the control house the soil temperature wasclosely related to the 24 hour average airtemperature until week 18. After week20 the difference became about 1.5-2.0°C in favour of the daily air temperature. It should be kept in mind thatthe insulation was applied to bothhouses. The soil temperature in the soilcooled houses was about 2.5-4.0°Clower than in the control house despitethe fact that the soil cooling system wasrunning continuously with 7-8°C supplyand return water. The soil temperaturein the soil cooled house increased to18°C during the month of July, ratherthan the 16°C it was aimed for, indicating the need for additional coolinglines in the house. In the soil cooledhouse the average daily soil temperatureat 7 cm was about 0.6°C higher and at 22cm it was about 0.6°C lower than at 15cm depth during July, there was littletemperature stratification in the housewithout soil cooling. »
SummaryThe excellent vase life combined with
low energy requirements during the winter make the production of Alstroemeriavery interesting. The results with theAlstroemerias look very promising withexcellent overall growth to date. It is tooearly to tell whether the control of thesoil temperature will be beneficial toAlstroemeria in the long term. D
December, 1985
Julia Brown Joins
Horticulture Crops Unit
Julia Brown has been appointedMarket Economist in the HorticultureUnit of Commodity Markets AnalysisDivision of Agriculture Canada.
Julia Brown graduated from theUniversity of Guelph with anAgricultural Economics Degree in 1983.Since then she has worked withAgriculture Canada with the MarketDevelopment Directorate where she wasProgram Coordinator for the CanadianAgricultural Market Development Fund(CAMDF) Program. In that position,she worked closely with industry todevelop projects whose principal objectives were to stimulate the increased useof Canadian agricultural products andaid in the development of effectivemarketing systems.
Julia grew up on a dairy farm thirtymiles west of Ottawa. She obtainedsome experience with the HorticulturalIndustry while working as an Assistantto Ontario Provincial Extension Horticulturists John Warner (Smithfield)and John Gardner (London) during thesummers of '80 and '81 respectively. Atthat time she had the opportunity towork directly with producers and in-
Keith's
DirectoryUpdate
It has been brought to our attentionthat we missed a few listings in ourKeith's Buyers' guide Directory. Themost embarassing example is omitting tolist "Ribbon" in our category index.Our apologies to the industry's ribbonmanufacturers and distributors.
Another "goof" was failing to list
Downham NurseryAnnouncement
Frank G. Kearny, President ofDownham Nursery Inc., is pleased toannounce the appointment of Paul R.Gagnon as the Company's chain storesales representative and liaison with itssales force of 5 other salesmen. PaulGagnon replaces Walter Bowley whoretired August 31, 1985.
Paul has extensive experience in thenursery industry, having worked for BosNurseries Limited in Trenton, Ontariofor many years. While with Bos Nurseries, Paul was involved in both landscaping and the retailing aspects of thebusiness and hence is familiar with theplant and technical requirements ofboth the garden centre manager andlandscape contractor.
dustry representatives on productionrelated issues. •
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Our apologies to Jack Keon and hissales staff.
Editor. •
Paul has a diploma from LoyalistCollege of Applied Arts & Technologywhere he studied business administration and chemical technology.He also received a diploma in Environmental Horticulture from the DurhamCollege of Applied Arts & Technology.
Downham Nursery Inc. is one ofCanada's oldest and largest growers ofnursery stock, growing over 500 varietiesof shrubs, trees, vines, rose bushes, fruittrees, perennials, evergreens and smallfruits. The Company farms approximately 700 acres of land and employs between 70 and 150 employees.Downham Nursery Inc. is unique in theCanadian nursery industry as it has a fulltime, professional sales staff of 6 people,supported by a head office staff of 3people. It is also the only company inCanada to utilize a full time quality control inspection staff to independentlymaintain a high quality standard. D
