Who among us is not yet longing for a blade of green to emerge from the cold, brown ground? This year, most of us will embrace mud season with open arms and await true spring – with its burst of forsythia blooms – with a joy tempered by the long winter.

True bliss will only come when we walk through the doors of our favorite greenhouses, when we smell that potting-mix-saturated air and feast our eyes on the vital green of the plants growing there. Then, spring will bloom in each of us. For most, the perennial journey to treasured horticultural establishments yields the same satisfying dividends: Shopping for seedlings and plants starts us on a path toward summer.

For greenhouse growers in Maine, this season has started on a different note than past seasons. Although shoppers won’t observe any difference in the quality of plants when they step into greenhouses this spring, the nature of the nation’s economic climate has trickled down to local greenhouses. Namely, the increasing cost of heating oil and gasoline is having an impact on the supplies needed to produce greenhouse crops. That, coupled with the late winter we’ve been having, may be a trying experience for large and small growers alike.

Although it’s normal for growers in central, northern and eastern Maine to experience temperature fluctuations, winter has hung longer in the air this year. “Normally growers would be past that really cold weather before they start burning oil,” Gleason Gray, a University of Maine Cooperative Extension educator, pointed out in a recent telephone conversation. “But not this year.”

Gray has his fingers on the pulse of the greenhouse industry in Maine. He’s trained as an agricultural engineer and knows just about everything concerning greenhouse design, construction and management. Those gardeners who have trained in the master gardener program in the Penobscot County area enjoy Gray’s lighter side as an educator who makes learning about gardening pure delight. But when it comes to matters regarding the greenhouse industry, Gray gets serious.

“The increase in fuel prices that greenhouse growers are experiencing are largely an unanticipated increase,” Gray said. “It takes roughly a gallon of oil to heat 1 square foot of growing space throughout the spring greenhouse season. As far as input costs go, heat and labor run neck and neck. They’re roughly equal costs.

“To heat the greenhouse all night, you’ve got to come up with about 300,000 Btu per hour depending on the size of your greenhouse,” Gray explained. On the coldest nights, heating a 3000-square-foot greenhouse to a temperature adequate to sustain, for example, a marigold crop, a grower plans on having an energy source that can output up to 350,000 Btu per hour, Gray said. One larger grower says this heating requirement will translate into a fuel bill of nearly $20,000 for the growing season.

While growers with smaller greenhouses can use wood heat, when all factors are considered, it is not economical for larger growers to use wood as an energy source. “When you factor in labor associated with wood, it’s not even close to the efficiency of oil,” Gray said.

In fact, the dramatic increase – of more than 40 cents per gallon in most cases – affects all petroleum-based industries, and is, in turn, affecting the cost of potting materials and other greenhouse supplies.

“Things are changing fast,” Gray reported. “The price of pots is increasing weekly.”

To add insult to injury, the increased cost of gasoline has added transportation costs to most goods. Some greenhouse suppliers are adding a fuel surcharge to growers’ orders. Others are adding a flat shipping rate to deliveries that just last year were a complementary service to growers.

“Growers may have to raise their prices,” Gray cautioned. Yet, he said, absorbing the increased costs is better than buying plants trucked in from destinations far away. “Overall locally grown plants are … a plus.”

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, 512 North Ridge Road, Montville 04941 or e-mail dianagc@midcoast.com. Selected questions will be answered in future columns. Include name, address and telephone number.