“A cold pocket” sounds like something a snowman might have. Meteorologically, I live where chilly-heavy air will linger on a breezeless night. Hence, one evening sooner than most, I’ll wake to find the pocket’s white lint—our first deep frost—lining each blade of grass, crystallizing flower petals, glazing pumpkins’ platter-like leaves. Denizens of Zone 5, we expect our first brush with frost to arrive anytime after the second week of September. I can try to avert damage to tender plants by casting blankets across the basil and tomatoes, by swaddling the fragile cuffs of morning glories in hopes of seeing one more bloom, but no amount of bedding will cushion the sharpening truth: Our growing season is over. Soon we’ll have the kind of frigid night that fringes all of our vegetation in a hoary ice. Certain plants’ cells can’t withstand this drastic temperature change. When the rising Sun warms a morning glory’s frozen leaves, its cell walls will break, irreparably. Eventually, the frostbitten garden will be blanketed with flakes. By then, we won’t be able to discern any difference between the snowman’s pocket and his voluminous white coat.