Geoffrey Charlesworth and Norman Singer gardened in Massachusetts. Both were renown for their rock gardens, and each of them sowed literally hundreds of pots of seeds of alpine plants every year. I remember Geoffrey telling me once that the ground never froze very much under the winter snow. For easy, commoner plants he would scoop the snow aside, crack through a couple of inches of frozen crust - just as Ellen mentioned - and the soil beneath was friable and suitable for planting. Here in NJ we can have frost two feet or more in the ground. Judy, in this week's monsoon belt where we're received 7.95 inches of rain, in three installments of 4.7", 2.7" (2 inches in one hour!) and .55". At that, there were places nearby that received significantly more.