A new applied research initiative in support of the ornamental greenhouse industry was launched in the spring of 2007 in response to requests by both Ontario growers and breeders/distributors.  With financial support from the Canadian Ornamental Plant Foundation and the Canadian Greenhouse Conference, Wayne Brown, Ontario Ministry of Agriculture, Food and Rural Affairs and Rodger Tschanz, Department of Plant Agriculture, University of Guelph worked together to evaluate the greenhouse production performance of 70+ cultivars of vegetatively propagated bedding plants in the research greenhouses on the Vineland campus.  Proven Winners, Dummen, Ball FloraPlant and Ball Seed/Sakata participated in the trial. The evaluators of the trial were especially interested in comparing the time to bloom or marketable stage, the need for growth regulation, free branching (need to pinch), disease and nutrient issues when grown relatively cold after establishment.  In general, the Ball FloraPlant liners had not been pinched at the rooting station, while those from the Proven Winners had been. Some of the series from Dummen were pinched by the rooting station and others were not . 

All plants were received as rooted liners and planted on March 5, 2007 into 11 cm pots in Sunshine#1 potting mix.  On March16, all petunias, calitunias, coleus and iresine were pinched.  During the 3 week period following transplanting, the trial material was grown at a day/night temperature of 20ºC and irrigated by hand using watering wand and breaker.   During this period the plants were fertilized with 20-8-20 at 150 ppm N.   On March 27, the plants were spaced on to a trough watering system where they remained until the shipping stage of development.  While on the troughs, all plants were fertilized with 100 ppm N of 15-0-15, three out of every four waterings; the plants were watered with clear water on the fourth watering.   After March 27, all the plants were grown at one day/night greenhouse temperature setting of 16ºC.  No supplementary or photo-periodic lighting was used in this trial. All plants received a wetting agent application (Aquagro 2000 at 15mL/1000L) on May 1 to improve the uniformity of irrigation between pots.  Evaluations took place on Mar 27, Apr 18, Apr 27 and May 1.  No chemical growth retardants were applied during the trial period.  Any pinching used for size management, is indicated in the table.   Two replicates, each consisting of 6 plants were evaluated.

An Open House was held on May 4th attended by numerous growers and industry representatives.

For bedding plant growers that prefer to grow cool most but not all plants do well at 16º C.  The upright forms of Angelonia when grown at an average16ºC D/N temperature were susceptible to Botrytis stem rot both at the soil line and up on the stem and clearly showed signs of iron chlorosis on the older leaves,

Based on our trial the Mini Supertunias were slower to flower and exhibited iron chlorosis when the others did not.  All petunia and Calitunias responded well to additional iron in the irrigation solution.  The Supertunias appear to be slower to flower because of their sensitivity to photoperiod.  Longer days are required to initiate flowers compared with the other series, especially the Potunias.

Chrysocephalum ‘Flambe Orange’ does not cover the soil surface as well as ‘Flambe Yellow’ because of its more leggy growth, and smaller green leaf.  It simply is not as attractive in the greenhouse.

Lobelia Waterfall lavender Light was very slow to flower and flowered sparsely at the low temperature.  Foliage was not as attractive as the others at the growing temperature used.

The second phase of this trial was the post-harvest aspect………….how the plants performed

• outdoors under Ontario summer conditions both in Guelph at the Turf Grass Institute and at Vineland. 

The second part of the trial was designed to test post-consumer performance of the same plants grown outdoors in containers. Two different sites, the Vineland Research Station and the Guelph Trial Garden (GTG) at the Guelph Turfgrass Institute, were selected for this trial to observe performance under different environmental conditions. The Vineland site was in an area adjacent to the greenhouse complex; this site was paved with asphalt and surrounded on three sides by low buildings.  The full sun exposure and sheltered nature of the Vineland site created a warm and at times, hot, microclimate for the test plants.  In contrast, the Guelph site could be characterized as being windy, surrounded as it was by turf research plots without windbreaks.  Like the Vineland site, the Guelph trial received full sun exposure; the container site at the GTG was covered by black fabric landscape mulch.  The spreading petunias and ‘SuperCal’ containers were placed on plant stands allowing the tops to be approximately 1 m off the surface of the mulch; all other containers sat directly on the mulch.  At Vineland the petunias and Supercalitunias’s were placed concrete blocks about 80 cm in height.

Because the plants were grown cool during the greenhouse phase of the trial and received no growth retardants, it was necessary to pinch the plants back during the second week of May to remove the leggy growth that developed due to high greenhouse temperatures of early May.  Four plants of each cultivar were transplanted into 50 cm patio pots from ITML and filled with Sunshine #1 potting mix during the week of May 21 and immediately moved outside for growing on.

The pots at each site were watered by hand using a breaker throughout the growing season.  The differing water quality and fertilizer delivery technology available at each site necessitated the use of different fertility regimes. At Vineland the crop was fertilised with 20-8-20 at 150 ppm N with every watering; the spreading petunias, callitunias (the ‘SuperCal’ series of  callibrachoa/petunia hybrids, iresine and coleus received 35 g/pot topdressing of Nutricote ( 14-14-14 Type 100) in addition to the constant feed in the irrigation water. All other plant species in the Vineland trial were fertigated only; additional iron chelate was added twice during the season to maintain foliage colour, particularly because a number of the Supertunia Mini’s that began to show iron chlorosis. No dead heading was done throughout the summer growing season.  At the Guelph site, all containers were watered when needed – at least every other day.  The high pH of the irrigation water necessitated using a pH -modifying fertilizer (Plant Prod pH Reducer 18-9-18) when fertilizing once a week at 300ppm N.  Every container at the GTG site received a top dress application of 70 g of Nutricote (14-14-14 Type 100) during the first week of June.  No iron chelate applications were needed during the growing season. 

Pest problems at both sites were limited to aphids on the ‘SuperCal’ series in Vineland and all petunias and ‘SuperCal’ entries in Guelph.  Both sites were sprayed twice during the season to control the aphid outbreaks.