Flowering dates of freesias (Freesia hybrida Bailey) sown at monthly intervals varied according to monthly temperature fluctuations over a 2-year period. Seeds germinated from April to June reached anthesis from December to March. April through June seeding dates were acceptable for obtaining optimal flower production and quality in Minnesota, but these plants were slower to flower than those seeded from July through November. Night interruptions by incandescent light hastened flowering, but flower quality was poorer than from plants grown under natural days. Short days and night interruptions using BCJ-Ruby incandescent lamps had no influence on flowering date.
Necrotic areas along leaf margins and at leaf tips were observed on Freesia hybrida Bailey when an aqueous application of hydrofhiosilicic acid (H2SiF6) was added to the growing medium. Similar foliar symptoms occurred with the addition of superphosphate or treblesuperphosphate which contains 1.0–1.6% F as a contaminant. Tissue fluoride levels increased when H2SiF6, superphosphate or treblesuperphosphate was added to the soil.
Seed germination of ‘Royal Mix’ freesia was most rapid and uniform at 15.5° or 18.5°C under clear polyethylene or at 13° or 21.5°C under black polyethylene. Soaking seeds in running water prior to germination or removal of the seed coat did not improve seed germination