SOG = Sea of green.
Take clones from a Mother plant and fill a grow space. All plants being the same genetic age of the Mother plant will produce similarly sized and yielding plants. Sea of green. The canopy is all the same height due to using clones which will grow with the same form and height.
A sea of green means that a grower has taken and propagated many cuttings into rooted clones of a Mother plant. This allows a grower to completely fill a grow space with these clones. The result is; All plants will be approximately the same size and yield is excellent due to the level canopy.