Shade

From Wikipedia, the free encyclopedia

For other uses, see Shade (disambiguation).

Shade is the blocking of sunlight (in particular direct sunshine) by any object, and also the shadow created by that object. It may refer to blocking of sunlight by a roof, a tree, an umbrella, a window shade or blind, curtains, or other objects.

Shade is an important issue in temperate and tropical zones for providing cooling and shelter from the sun. Providing certain configurations of shading is an important passive solar technique. This may be done with overhangs, with shade trees, or with vines. Vines particularly suited for this purpose include Boston ivy, Virginia creeper, and morning glory.

Shading using non-living materials blocks the sun, but also results in sunlight being absorbed and re-radiated as heat, or in sunlight being reflected as glare. Green plants, on the other hand, not only absorb a significant portion of the sunlight to invest as energy in photosynthesis to produce sugar, but also actively transpire, producing an additional cooling effect.

In gardening terms, there are various types of shade: Full sun - more than five hours of direct sun per day. Part shade - two to five hours of direct sun, or all-day dappled sun (sunlight shining through open trees). Full shade - less than two hours of direct sun per day.