So, to be sure of uninterrupted darkness, move the plant into a closet during each night period. Maintain the uninterrupted 14 hour dark periods for about 10 weeks but be sure the plant has bright sunlight during the day. With a little luck the plant should be in glorious bloom for Christmas. That depends upon who you ask. Some gardeners without scientific data to back up their claims swear by planting by the right moon phase.
Scientific evidence is against it.
Controlled experiments in the greenhouse with tomato and maize seeds, both supposedly sensitive to lunar effects, failed to show any consistent effect of the moon on germination. Outdoor plantings of radish, cabbage, bean, onion, and carrot seeds weren't affected by the moon either. No correlation was found between the moon phases and germination or early seedling development of spruce. One experiment in South Africa suggested that moonlight at half moon hydrolyzed starch in leaves of Tropaeolum and spinach and in tree sap. The starch disappeared from uncovered portions of the leaves upon exposure to moonlight, and there was nearly twice as much reduction to sugar in tree sap following the half moon than after a period of minimum light.