Answer: by using artificial light (grow light) in place of sunlight
Explanation: Plants generally needs sunlight to grow and survive through a process known as photosynthesis, this is when Plants and other organism uses sunlight to convert water, carbon dioxide and minerals into energy rich compound (starch) while oxygen is been released into the environment.
However in the absence of sunlight, artificial light know as grow light can be used, these lights are design in such a way that it emits lights of wavelengths that are appropriate for photosynthesis. The grow light replaces the sun as a source of photons in the process of photosynthesis.