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The first study was undertaken during fall 1989 and the second in winter 1990 using Callistephus chinensis `Pink Carpet', and Calceolaria herbeohybrida `Anytime mixture' seedlings. In both experiments, four photosynthetic photon flux levels were used; 30, 60, 90 and 120 mmol m-2 s-1 to obtain a 16 hr photoperiod. All lighting treatments were provided by HPS lamps (400 W) and compared to natural light condition (control). The utilisation of this electrotechnology not only increased vegetative growth but also reproductive development which resulted in shortening production time. Flower number was also greatly enhanced. Differences measured between control plants and those having received a supplementary light treatment were greater during fall 1989 than winter 1990 study.
Geranium seedlings (Pelargonium ×hortorum Bailey `Smash Hit Red') were given various cold pretreatments (CP) to obtain more rapid adaptation to constant or split-night temperature regimes. The six following CP were used: either 13C or 17/13C for 5, 10, or 15 days. The effect of these CP given at seedling stage was compared with that of control plants held at 17C at night. The CP did not significantly increase the time to first visible flower buds or to anthesis. The number of flowering stems, plant height, shoot dry weight, and leaf area of control plants were not significantly different from plants receiving CP.
Seeds of Matthiola incana `Pink Appleblossom' and `Miracle Crimson'(stock) and Godetia Whitneyi `Grace Rose Pink'(godetia) were sown into 200 unit plug trays containing Pro-mix. Seedlings having 4 to 6 true leaves, were transplanted into ground beds containing a substrate composed of 40% sand, 45% loam soil and 15% peat moss (vol/vol). Stocks were planted at densities of 60 et 90 plants/m2 and godetias at 20, 30, 40 and 60 plants/m2. Plants were grown under ambient light conditions or a photosynthetic photon flux (PPF) of 60 μmol m-2s-1. After seedling stage, air temperatures were maintained at 18°C (day) and 13°C.(night). During the production cycles of fall-winter 1991 and 1992, a supplemental PPF reduced total production time by 26 et 27 days respectively. Supplemental light caused a reduction of stem length. Planting density did not effect the variables measured. With godetia, the supplemental light treatment significantly increased the number of saleable stems. Marketable yield increases were not proportional to higher planting densities.
In the summer of 1992, a 4-year research program on the utilisation of propane in agriculture was initiated between ICG Propane and Lava1 University. Experiments were conducted to evaluate the effects of propane burners on weed control as a pre-establishment treatment. The data indicate that the efficiency of weed control is related to tractor speed and gas pressure. When weed height is between 1 and 2 centimetres, most of the heat treatments were as effective as those with the herbicide paraquat. The best and most economical heat treatment was at a tractor speed of 6 Km-hr and a gas pressure of 65 PSI. With larger weeds, efficiency increased with reduces tractor speed and increased gas pressure. In addition, high intensity treatments provided excellent control on broadleaf weeds but were less efficient on grass species. A preliminary economical evaluation showed that propane burners are competitive with chemical herbicides and large-scale commercial trials are planned for summer 1994.
During Winter 1994, seedlings of Impatiens wallerana `Accent Coral' and Pelargonium ×hortorum `Orbit Hot Pink' were grown in commercial substrate (Pro-Mix BX) or in one of the 24 substrates composed of six organic residues (composted water-treated sludge, forestry compost, fresh or composted used peat extracted by a biofilter during treatment of municipal water, and fresh or composted paper sludge). These residues were incorporated with peatmoss and perlite at 5%, 10%, 25%, and 40% per volume to obtain the 24 substrate combinations. Plants were watered and fertilized by flooding of ebb-and-flow benches. Growth measurements (growth index, top and root dry weight, number of flowers and buds, visual quality) varied considerably depending on the percentage of residue incorporated into the substrates. Moreover, substrates containing 40% of organic residues are not recommended for production of impatiens or geraniums.