Anemone (Anemone coronaria L.), snapdragon (Antirrhinum majus L.), larkspur [Consolida ambigua (L.) P.W. Ball & Heyw.], delphinium (Delphinium ×cultorum Voss.), sunflower (Helianthus annuus L.), lupine (Lupinus hartwegii Lindl.), stock [Matthiola incana (L.) R. Br.], and pansy (Viola ×wittrockiana Gams.) were grown in raised sandy loam ground beds in double-layered polyethylene-covered greenhouses which were either unheated (ambient) or had a 55 °F (13 °C) minimum night temperature in year 1 and 36 or 50 °F (2 or 10 °C) minimum night temperature in year 2. Results were species specific; however, the extreme low temperatures [21 °F (-6 °C)] in the unheated house limited delphinium and lupine production. The warmest greenhouses (55 and 50 °F) reduced production time for anemone, delphinium, larkspur, lupine (year 2), snapdragon (year 2),stock, and sunflower. The coolest greenhouses (unheated and 36 °F) increased stem lengths for anemone (year 2), delphinium, larkspur (year 1), lupine (year 2), snapdragon, stock, and sunflower. The coolest green-houses also yielded a profit or lower net loss for all species except delphinium, lupine, and snapdragon (year 2) for which profits were highest or net losses were lowest in the warmest greenhouses.