Winter frost on grass, Berwick -upon-Tweed, England.

On a clear Winter night soft white crystals form. They form on vegetation, or any object that has been chilled below freezing point by radiation cooling, these crystals are called frost.  The interlocking crystals become attached to branches of trees, leafs, hedgerows and blades of grass.  This deposit of crystals is known as hoar frost, and can be so thick that it appears as snow.