Mid-April and there is still snow on the garden. The day’s cold rain has reduced it to patches along the border with the woods. Chill winds howl around the house; the lights flicker. Writing is interrupted by a sense of urgency to fill lamps with oil and buckets with water.

Each April storm has left me hoping it was the last, that in its wake daytime highs would signal plants and insects, both friend and foe, to get on with spring. But storms keep coming. Everything waits.

Gardeners, plants and insects all wait for the same signal, an accumulation of Growing Degree Days that initiates emergence from winter’s dormancy. GDDs begin to accumulate when daily temperatures rise above 50 degrees Fahrenheit; for a given day, every degree above an average of 50 is one GDD. For example, a day with a low of 48 and a high temperature of 52 degrees would add two GDDs to the accumulated total. (For the purpose of calculating GDDs, temperatures below 50 degrees F are set at 50 degrees F).

As of this writing (April 16), only four GDDs have accumulated in the Ellsworth area, all in late March. The flower buds of red maple are still tightly closed, waiting. Crocuses and daffodils still sleep within the ground, keeping the gardener waiting.

Thinking about the transition from winter to spring brings wonder at nature’s synchrony, at the emergence of leaf-chewing insects timed so precisely with the unfolding of the leaves they eat. Larvae of viburnum leaf beetles, for example, remain curled in their eggs until the viburnum leaves begin to unfold, both beetle and leaf responding to similar levels of accumulated GDDs. Smart gardeners take advantage of this, carefully examining the tips of naked viburnum stems for rows of egg casings, pruning them off and burning them before leaves and larvae emerge.

Equally marvelous timing can be seen in the awakening of pollinating bees as the flowers they forage for nectar and pollen begin to open. Today, encased within the mud-capped cells of a nest box in Marjorie’s garden, adult orchard bees lie wrapped in their cocoons, waiting for maple flowers. It has been a long wait – the eggs were laid last spring.

Soon, after a few days at 57 degrees F, male bees will emerge and sit in the sun, waiting for females to emerge. Another few days above 57 degrees and the females will emerge, mate immediately, and then fly off to find and provision nests for their eggs.

The female orchard bee will visit nearly 2,000 flowers to provision a single cell. She will collect pollen and nectar until she has accumulated a pollen lump in the cell, and then lay her egg on the pollen lump. She will then construct a mud wall to seal that cell from predators and parasites. When the wall is finished, she will fly off to provision another cell for another egg, repeating this process 30 times, pollinating 60,000 flowers.

Now, nearly a year later, the emergence of bees from the nest coincides with the opening of the flowers of red maple and other early-flowering plants. Both bee and flower respond to the same temperature signal, to the same number of accumulated GDDs.

We are connected by this vigil, gardeners, bees and beetles, along with the plants we depend upon. Together, we wait for the signal.

Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to reesermanley@shead.org. Include name, address and telephone number.