Clumps of assorted weeds poke through moss-clogged gaps of the old, brick sidewalk on this narrow street.

Most people would dismiss the unsightly intruders as more nuisance than anything. Some Roundup should do the job. Or, especially in this Center City neighborhood, the environmentally astute would likely get down on hands and knees, pull the things out, and throw them in the compost heap.

But not Lynn Landes.

The 56-year-old wife and mother of three surveys her block off Locust with satisfaction. Between the bricks and along the paved edge where she parks her Prius, Landes sees wild violet, plantain, and Japanese knotweed - tasty salad greens for the evening's dinner.

"It's a very mild taste," she says, plucking a tender round leaf and popping it in her mouth.

Landes, who also knits her clothes, no longer wears jewelry or makeup, and does not use soap, is what some might call an extreme ecologist, a person who thinks constantly about her impact on the planet and then takes steps, often far off the beaten track, to reduce that footprint.

Since the first Earth Day 39 years ago, considered the start of the modern environmental movement, most of us have come to understand that the world needs care. We dutifully recycle plastic bottles. Maybe we drive a hybrid or opt for wind energy.

Then there are folks like Landes. She, and the many like her, take a decidedly different approach to environmentalism. Their actions are beyond green. They are what some call dark green.

"I'm always just experimenting," says Landes, black and gray curls (no hair dye, of course) framing her face, which for two years has been cleansed with pale green onion juice.

Ultra-environmentalists use composting toilets. Sew cloth sanitary pads. Give up air travel. Shun plastic. Recycle everything - including the staple on a teabag.

A survey released last year by PR firm Porter Novelli of 11,700 Americans in its database found that 7 percent fit its generous definition of dark green. That segment did all seven identified environmental actions, such as buying environmentally friendly products that use less packaging, consuming less energy at home, and recycling.

For true extreme ecologists, of course, those endeavors are hardly novel. The ways they slash impact might seem eccentric, even carborexic. The term surfaced last year to describe an unhealthy compulsion to reduce one's carbon footprint, akin to anorexics who count every calorie at the expense of all else.

But dark greenies also look a lot like trailblazers, the early adopters of sustainable practices that might become as common as flipping off a light switch when leaving a room.

"Today's threats demand that we hone a new sensibility, the capacity to recognize the hidden web of connections between human activity and nature's systems . . . ," psychologist and author Daniel Goleman argues in his new book Ecological Intellegence: How Knowing the Hidden Impacts of What We Buy Can Change Everything. "This awakening to new possibilities must result in a collective eye-opening, a shift in our most basic assumptions and perceptions, one that will drive changes in commerce and industry as well as in our individual actions and behaviors."

That consciously taken path to dark green, though, is speckled with gray. Do I need that? How was it made? How far did it travel? What happens to it when I discard it?

Consider the possibilities

In recent years, the Carnwaths of Wayne have eschewed buying plastic, all plastic - no easy task with a toddler and baby.

That means Steve, 43, a computer programmer, crafted the wooden trike that 3-year-old Josiah wheels around the front yard and the small red car (painted with milk-based color) he plays with in the living room. That also means the hunt for Parmesan cheese requires research worthy of a dissertation.

"Most of our food we try to buy organic," says Ronda, 36, who stays home with Josiah and 9-month-old Lydia. "But we can't find organic Parmesan cheese in a glass container. It's all plastic."

Adds Steve: "You could buy it in the chunk form, not grated, but you have to wrap it up in the plastic wrap to get it home."

The final decision? "We go with the glass jar, non-organic," Ronda says.

Yogurt was another challenge. "We go through so much yogurt, a couple of containers a week," Ronda says. "That's 104 containers for the year." The calculus of a dark green life is often figured that way.

So, they make yogurt from scratch, using raw milk (sold in reusable glass jars) from a local farm. Ronda also mixes her own laundry soap to forgo the plastic jugs. Of course, the Carnwath children use cloth diapers. Steve hunted down pins that are all metal, no plastic head.

But the project that draws the most raised eyebrows sits in a basement corner: a handmade toilet. Designed after one featured in The Humanure Handbook that Steve read years ago, the 5-gallon bucket (alas, plastic from Home Depot) is gussied up inside a pine box with a wooden toilet seat and an attached storage cabinet. It doesn't smell, honest.

When two buckets of business accumulate, Steve - yes, it's his job - empties the waste in a fenced-in compost pile on his one acre. He piles several inches of leaves on top. "It all breaks down," he assures. After two years, the mix delivers a nutrient-rich, sweet-smelling dirt perfect for the vegetable patch.

"It's odd; you have to agree with that," Steve allows.

But it makes more sense to him than the status quo. The toilet, he says, is "an exercise in better understanding the effect we're having on the environment. . . . People have this belief in a place called away. You throw things away. They just go somewhere else. It has no bearing on you. But away doesn't exist."

Environmental pioneers

Writer Colin Beaven understands better than most how extreme greens think.

"What they're doing sounds wacky. But that's just because they're at the very beginning of experimenting," says Beaven, author of the book No Impact Man, due this year, that chronicles his 2007 experience when he and his family lived off the grid - in Manhattan. "They're doing all of us a favor by saying, 'Let's look a little more carefully at how we're living.' "

Since the 1970s, when major federal conservation laws were passed, the environmental movement has moved firmly to our backyard, where concerns center on health and reducing consumption. This decade's buzzword is sustainability, both in lifestyle, and increasingly, business. Reduce, reuse, recycle is the mantra.

"We don't have a bunch of extra planets to access resources nor dump our waste," says Zenobia Barlow, executive director of the Center for Ecoliteracy in Berkeley, Calif. "This is it."

Meenal Raval of Mount Airy arrived at that moment of introspection, like many dark greens do, after she saw Al Gore's 2006 documentary on global warming, An Inconvenient Truth. "How much am I contributing to this disaster?" she wondered.

Raval, 46, took steps to whittle her footprint. The most dramatic came in 2007, when she decided not to go ahead with a flight to India, where she keeps her late grandmother's apartment as a winter retreat. The 15,000-mile trip alone, she calculated, would have contributed 6,600 pounds of CO2 and would have wiped out all the progress she had made by trading down to a subcompact and installing a programmable thermostat.

"I don't see a reason to fly," says Raval, who also has since dispensed with trips to London and domestic flights. She got her husband, Afshin Kaighobady, 50, to eventually go along. "I've seen California. I go to the Jersey Shore," she says. "I feel more rooted in the immediate geography."

Across town in West Philly, lawyer turned "challah man" Michael Dolich, 39, runs the no-waste - well, almost - Four Worlds Bakery. He eventually throws out thin sheets of soiled parchment paper into the bakery's only trash can - a 13-gallon receptacle the size of a typical kitchen bin - but he's working on a cost-effective alternate.

Dolich is guided by a triple bottom line, also known as the three P's - prosperity, people, planet. That means he wants a financial profit, like a traditional business, but he also cares about his (and his one employee's) quality of life and his impact on the community.

Test loaves of bread, usually discarded, are donated to a nearby soup kitchen. Individual customers and cafes pre-order fresh baguettes and bagels, croissants and olive loaves through the Web. Orders are delivered to city pickup spots through Pedal Coop's bike carts and to suburban ones through customer volunteers, who are headed outside the city anyway. The bread is packaged in reusable totes (not paper or plastic bags) that rotate between customer and bakery. Otherwise, Dolich would go through "thousands of bags," he says. "What a waste."

It's easy to caricature people like Raval (no-fly woman), Carnwath (toilet guy), and other extreme ecologists. But rather than eco-freaks, environmentalist Eric A. Goldstein calls them "environmental pioneers."

"This is the extreme end of a more popular public reaction, which is seeking to live a healthier and more sustainable lifestyle," says the urban program coordinator for the Natural Resources Defense Council based in New York.

One woman's way

For Lynn Landes, her path started innocently enough, a Bucks County mother whose children developed allergies and chemical sensitivities. By the '90s she was an activist agitating against landfills and a member of the state's Solid Waste Advisory Committee.

It snowballed. Now the kitchen of her 1,200-square-foot rowhouse (downsized from a 2,300-square-foot suburban spread) has no plastic save for the half dozen 6-inch pots (she's looking for a sound alternative) in which she grows herbs and plants carrots, celery, and beets just for the green tops.

Landes favors organic but notes that's not good enough. "It should really be organic and local" - the best local coming from her own efforts. "There's something pathetic about being a consumer. I hate that word." That's one reason she doesn't buy salad greens but grows and forages for them. "I found this right behind Alumni Hall at Thomas Jefferson," she says, pointing to a dense clump of straggly chickweed. "It was growing between the curb and the street."

She also has pots of scallions. Instead of soap products, Landes - and now her husband, Cliff, 66, a retired pilot - cuts a finger-long piece of green onion stalk, slices it open, and rubs it on her face, a soap substitute gleaned from the Internet.

For bathing, she mixes scallions with water in a blender. "It's kind of cheating if you want to go the no-energy way," she allows. The concoction is strained and added to the tub. The juice, along with apple cider vinegar, also makes a good household cleaner, she says.

"It's surprising how clean it gets you," says Cliff, adding, "You hardly smell it."

Like many dark greens, Landes is motivated not only by the fate of the planet but also by her own health concerns. "I don't put anything on my skin that I wouldn't put in my mouth because your skin is your largest organ," she says.

Around the same time she gave up soap, she abandoned makeup and perfume and chucked jewelry, because she didn't want to contribute to the mining of metals or to sweatshops and child labor.

"The only thing I have left is a ring," she says, extending her left hand with a thin gold wedding band. "I had taken that off and my daughter had given me a wooden ring. It got brittle and broke 'cause of water. I'm still looking for a replacement."

Compromise is often part of the dark green way. But Landes, for one, is not discouraged.

"If you're trying to do a low-impact life, you chip away at things you don't have to do," she says. "This is an evolving process. Just because you can't do it all doesn't mean you should stop chipping away."

Green Tea Bag

Scott Kelly, 41, of Chestnut Hill; principal of Re:Vision Architecture, Manayunk.

Green extreme: Runs a super-green firm. Skylights reduce use of electric lights. Dual-flush toilets save water. Employees who live 10-plus miles away must work from home once a week. Employees who buy homes near the office - within walking/biking distance - get an average of $6,000 toward their down payment. Dry cleaning is discouraged. Everything is recycled, including the tea bags: paper tab to recycled-paper bin, bag with tea leaves and string to compost bin, and the staple to recycled-metal bin.

Why: "If you know what your impact is, you have to make harder choices. The goal isn't to be religious about it. We just have to make informed decisions."

Naturally Absorbent

Jennifer Mettler, 38, of Gladwyne; stay-at- home mother of two.

Green extreme: Reusable cloth sanitary pads. Made of 100 percent organic cotton, the pads (Lunapads and GladRags brands) have flaps that snap around underwear. Liners offer added protection. Washes and dries.

Why: "First of all, it definitely cuts down on stuff going into the landfill. Second, it's just better for you. They're comfortable. … It's really not that gross. They totally come clean. They don't stain."

Garden-Variety Abundance

Celia Martin, 46, gardening teacher, with Kimberton Waldorf School, a pre-K-12 school in Kimberton, Chester County, which emphasizes "handwork," including knitting, wood carving, sewing, and the natural world.

Green extreme: Two-acre biodynamic (a type of ultra-organic) garden. Students plant, maintain, and harvest all kinds of vegetables, fruits - red raspberries are made into jam - various herbs, and many flowers (daffodils decorate lunch tables) as part of the sixth- to 10th-grade curriculum. The bounty helps supply the school's vegetarian lunch program, Food for Thought.

Why: "It helps the kids connect to the earth. We're not trying to teach them to be farmers and gardeners. We're trying to teach them how it works in nature, what it takes to produce the food that ends up on their plate."

Minor Recycling? Hardly

Aedhan Loomis, 14, of Fitler Square and a ninth grader at Germantown Friends School.

Green extreme: Persuaded his family of four to save milk cartons, all plastic (through No. 6), butter wrappers, foam meat trays, batteries, etc. Sorts and then hauls (Dad drives) monthly to Recycling Services Inc., Pottstown. Recently made an offer to 200 neighbors to do the same for a $10 monthly fee (to cover truck rental and labor).

Why: "It just adds up. You see all this recycling and all this energy really thrown out on the street or put into landfills. … I'm thinking about my future, my planet, my children."

- Lini S. Kadaba

Contact staff writer Lini S. Kadaba at 215-854-5606 or Lkadaba@phillynews.com.