At first glance, it looks as though little happens at the Yale Organic Garden in February. Leaf-covered vegetable beds flank two plastic-covered, unheated greenhouse frames sitting roughly in the center of the football field-sized garden plot. There are few signs of life.

But every Friday and Sunday afternoons, weather permitting, a small group of University students still comes to work in the garden. From planting avocado seedlings to turning compost, these volunteers brave the cold to maintain a variety of winter garden projects.

This past Friday, these volunteers stood huddled around Lucas Dreier ’05, an employee of the Yale Sustainable Food Project, and waited for their workday instructions.

But first comes a mini-lesson in organic gardening. Dreier briefly discusses a new tool that the garden has recently obtained: the “tilther,” part of a new line of tools specifically targeted at small-scale organic farms like Yale’s. Different from a Rototiller, it allows farmers to disturb only the top few inches of soil as they till the ground. Regular tilling is “a violent process that disturbs soil structure,” Dreier said. The tilther, in contrast, maintains the soil’s integrity while still disturbing it enough to prepare it for planting.

Having learned their piece of garden trivia for the day, Friday’s volunteers are put to work moving leaves from a 15-foot-high pile in the corner of the garden to a flower bed. This year, the garden received a sizeable portion of Yale’s leaf matter collected from the main campus — about two-thirds of the total campus leaf volume, according to Dreier.

“These leaves will be our source of fertility for the spring,” said Josh Viertel, director of the Yale Sustainable Food Project and manager of the garden.

Collecting and using leaves from the main campus is a way of integrating what would be part of the University’s waste stream into a cycle of soil health; leaves provide insulation for plants and decompose into organic soil matter. Yale saves money as well, since it does not have to pay fees for leaf disposal as it did in the past.

Along with maintenance tasks, such as prepping flower and vegetable beds with partially composed leaves, Dreier says, there are three main tasks that take place in the garden in winter. The garden grows cold-tolerant crops in its on-site unheated greenhouses, harvests crops like parsnips that are tolerant enough to spend the winter in the ground, and starts seedlings in the heated greenhouse of the Marsh Botanic Garden, just up the hill on Prospect Street.

“Winter work is just great,” Viertel said. “We’ll be pruning fruit trees, keeping the sides of the greenhouses shoveled after the snow, getting our plantings ready for the springtime.”

A look inside one of the greenhouses, where volunteers are pulling out old lettuce plants in preparation for a new planting, demonstrates a few of the possibilities for winter gardening. The garden has three greenhouses, unheated metal structures that are covered in plastic in the winter and left open to the air in summer. Inside, dense carpets of salad greens spread vibrant hues over the rectangular beds — there’s claytonia, a cold-loving salad green, spinach, a variety of kale and a red-leaf lettuce. Contrary to common belief, there are many plants that grow well in the cold — including radishes, salad mixes, carrots and kale.

“We’re definitely selecting varieties that are more cold-hearty,” Dreier said, speaking of the crops that are currently flourishing inside the greenhouse. “It’s amazing what cold temperatures they will grow in.”

Viertel cites Elliot Coleman, an organic farmer from Maine, as a major inspiration of four-season garden productivity.

“He has greenhouses full of beautiful produce,” Viertel said, referring to Coleman’s farm in winter.

Using greenhouses, both heated and unheated, Coleman’s methods are an inspiration for year-round garden productivity, Dreier said.

“If you go up to his farm in Maine in the middle of winter, he’ll pick you out fresh vegetables,” he said.

The Yale Organic Garden is not yet on par with Coleman’s, as biodiesel fuel-heated greenhouses remain dreams of future winters for the farmers here on Edwards Street. But even the winter productivity of this year’s garden is notable. Tenley Wurglitz FES ’07, a garden volunteer, said she was surprised at the amount of work that went on in the cold months.

“I didn’t realize you could grow so much in the winter,” she said.

And there is much to anticipate, such as the planting of seedlings for the spring, the seeding of the greenhouses for more winter salad mix in just a few days, and the harvesting of some fall-planted crops such as parsnips, a carrot relative that spends the winter underground and is now full of flavor, ready to be harvested and eaten.

The garden is now looking forward to its fourth season as this spring — a more traditional gardening season — arrives.