Simply put, hydroponic gardening is method of growing plants without soil. It’s a way to nurture a huge variety of edible plants (think herbs, veggies, even some fruits) indoors all year round, regardless of what Mother Nature is doing outside your door. Indoor gardening is a technique used to grow plants indoors. … Hydroponic gardening uses no soil at all. Instead, it relies on growing plants in water (usually attached to a floating substrate), and the use of additives to provide the nutrients that would come from soil if the plants were grown outdoors.