Maximizing the productivity of short-day plants

Added on 05 December 2022

Tags

Maximizing the productivity of short-day plants

While poinsettias are typically associated with Christmas, they can be found blooming in nature during the month of December. This is because they require exposure to shorter days and longer nights to bloom. Today, most poinsettias sold in the U.S. are grown in greenhouses with light deprivation so that they will be ready for sale a month earlier than if they were left to grow naturally.

Many people new to controlled environment agriculture associate light deprivation with cannabis as it is a common technique used by growers to induce flowering in cannabis plants. By modifying the lighting schedule from an 18-hour photoperiod to a 12-hour one, growers can trigger their plants to enter the flowering stage. Greenhouse growers who are cultivating cannabis year-round may use light dep curtains and light traps on their fans and vents to block sunlight for a few hours in the morning or evening, especially in the summer when daylengths are longest. This technique can be used to great effect to produce high-quality buds.

As the days grow shorter in autumn and winter, many plants naturally enter into their reproductive stage. These plants are short-day (SD) plants and include poinsettias, cannabis, Christmas cactus, chrysanthemums, and asters. When daylengths are long, these plants will remain vegetative, happily growing leaves and stems. As the days get shorter, however, these plants start to transition into their reproductive stage, reallocating resources from leaf production to flower production. Over time, as SD plants are continuously exposed to short day lengths, their flowers fervently grow and blossom into the blooms we love. Thus, by changing the amount of light exposure these plants receive on a daily basis, gardeners can manipulate when these plants grow and share their festive blossoms.