Our clones are kept under 24-hour artificial light to keep them in a vegetative state while they wait to be purchased. If the intended growth environment is indoors, it is important to use proper horticulture lighting to achieve results.
As previously stated, clones are kept under a 24hr light cycle at Airfield, however, this is typically under a very low-powered LED light. This means if you were to expose your clone to a harsh HPS grow light, the harshness of the light would likely put your clone into shock and kill it. For the first 4-7 days, avoid HPS lights and direct sunlight. Then gradually ween the clone into the desired lighting by starting with 1 hour and increasing the amount of direct light by one hour until it can stay under HPS for a full lighting cycle.
Cannabis clones require 18 hours or more (up to 20 hours) of light each day in order to grow as big as possible. This is called the vegetative state where they accomplish a majority of their growth. Once you bring your clone home, it is recommended that you keep it under normal lights (like a desk lamp or low powered LED light) and gradually reduce the amount of light your plant receives by approximately one hour per day until you've reached your desired daily light cycle. Altering the light cycle (such as adjusting from 24 hours to 18 in one day) will create stress on the plant and undesirable growth including (but not limited to) seeds, fluffy/airy bud structure, or potentially the death of your clone.
When you feel your plant is ready to produce, switch the light cycle to 12 hours of light and 12 hours of complete darkness. Using a lighting timer will help keep the plants on a consistent schedule.