Petunia × hybrids `Snow Cloud' plants were grown under 25 temperature combinations ranging from 10 to 30C and at photosynthetic photon flux levels of 100 or 200 μmol·s-1·m-2 (6.5 and 13 mol·day-1·m-2, respectively). Days to flower-was a quadratic function of average temperature, with 25C being the optimum temperature for minimal tire-e to flower at 200 μmol·s-1·m-2. Plant height increased “linearly and average internode length increased quadratically as day temperature increased. The number of lateral shoots decreased quadratically as average temperature increased, and the average length of each shoot decreased quadratically as day temperature increased.

The effects of storage conditions before transplanting were examined for Petunia × hybrida Vilm. 'Supercascade Lilac', viola × wittrockiana Gams 'Universal Beaconsfield', and Salvia splendens F. Sellow ex Roem. & Schult 'Red Hot Sally'. Plug grown seedlings were stored for 0, 7, 14, or 21 days at 5 or 10C and with continuous irradiance levels from incandescent bulbs at 0, 2, or 12 µmol·m -2 ·s -1 . A second group was stored at 18C with irradiance from fluorescent bulbs at 105 µmol·m -2 ·s -1 and a 16-hour photoperiod for the same durations. Temperature was more important than irradiance in maintaining a commercially acceptable plant during the storage period. Petunia and pansy could be stored successfully for 21 days at 5 or 10C with no appreciable loss of quality; salvia could be stored for a minimum of 14 days. Seedlings of all species elongated excessively when stored >7 days at 18C and 105 µmol·m -2 ·s -1 irradiance. After 14 days of storage, petunias stored at 18C flowered sooner than those stored at 5 or 10C but time in a production environment (days to flower -days in storage) was similar for petunias stored at 5 or 18C.

Pelargonium×hortorum L.H. Bailey `Scarlet Elite' seedlings were grown in plugs from seed to transplant size. About 14 days before attaining transplant size, seedlings were exposed to various fertility or temperature regimes (preconditioning treatments), then stored for 1 to 3 weeks at 5C. Seedlings receiving 150 mg N/liter before storage flowered sooner and required less crop time (days to flower – days in storage) than those receiving 0, 75, or 300 mg. Temperature preconditioning at 10 or 15C delayed flowering compared to preconditioning at 20C. Final plant height and dry weight were not adversely affected by varying N levels or temperature during preconditioning. Preconditioning seedlings with 300 mg N/liter resulted in seedling mortality rates up to 16% after 7 days' storage. Low temperature or fertility were not effective preconditioning treatments. Best results were attained by preconditioning seedlings with 150 mg N/liter.

No abstract

Methods of cold storage for rooted cuttings of three cultivars of Pelargonium ×hortorum Bailey were examined. Cuttings were stored from 0 to 10°C for 7 to 56 days. Treatments included packing the cuttings in ice, storing them under irradiance levels of 0 or 50 μmol·m–2·s–1, applying fungicides, varying cutting developmental stages, and varying the day temperatures. Cuttings packed in ice showed signs of chilling injury within 7 days and died. Applications of etridiazole and thiophanate-methyl or metalaxyl and thiophanate-methyl drenches or fosetyl-Al spray did not improve storage performance of the cuttings. Roots of cuttings held 7 additional days in the propagation area before storage grew faster after storage than those of cuttings with less time in the propagation area, but flowering time was not affected. Maintaining night temperatures at 5°C while allowing day temperatures to rise to 10°C delayed flowering by 6 days compared to maintaining a constant 5°C. Rooted cuttings held at 5°C under 50 μmol·m–2·s–1 irradiance for 9 hours each day could be stored up to 56 days with only a 2-day delay in flowering compared to unstored cuttings. Chemicals used were 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole (etridiazole); thiophanate-methyl (dimethyl[1,2-phenylene)bis(iminocarbonothioyl)]bis[carbamate]) (thiophanate-methyl); N-(2,6-dimethylphenyl)-N-methoxyacetyl) alanine methyl ester (metalaxyl); aluminum tris (O-ethyl phosphonate) (fosetyl-Al).