The influence of temperature, daylength and irrigation on the growth of tomato seedlings of the variety Kurihara under low light intensity was investigated. The results are summarized as follows. 1. Low light intensities of 1/3 to 1/6 that required for maximum photosynthesis were attained by planting seeds on Nov. 5th and 30th and also on Dec. 10th. and 30th. 2. High temperature, natural daylength and heavy irrigation increased the vegetative growth of the seedlings, but the growth of flower bud was not affected by these environmental factors, 3. Temperature, daylength and irrigation did not influence the time reguired for the floral initiation. At lower light intensities more time was required. 4. The number of leaves to the first inflorescence was affected by low temperature but not by daylength or irrigation. 5. The number of flower buds and degree of floral development under low light intensities was significantly affected by light intensity, daylength and irrigation. 6. Early and highest total yields were obtained from 20°and 25℃ plots grown under natural daylength.