Mike McGrath is something of a legend among organic gardeners. He was the highly idiosyncratic editor of Rodale's Organic Gardening magazine throughout most of the ’90s. Under his leadership the magazine became the most widely read gardening magazine in the world, and McGrath regularly made the rounds of the Today Show and Good Morning America, dispensing organic gardening wisdom to the masses. But mostly OG readers remember him for his wildly offbeat garden column, which might veer from seed-starting to digressions on the consequences of endorsing the wrong school board candidate in a small town to the behavior of inebriated birds drunk from the fermented crabapples still hanging on the tree far too late into winter.

If that sounds like it was too good to last -- well, it was. The high sheriffs at Rodale decided to make a change. "They wanted to repurpose the magazine," McGrath told me on the phone last week. "They thought it needed to appeal to women more. Well, the only reason I was gardening was to please my wife." Be that as it may, he went back to writing health stories for another Rodale publication -- Prevention -- and right about then a public radio station called.

"It was WHYY in Philadelphia," he said. "They wanted me to develop a gardening show for them. At the same time, Pat Stone called and asked if I'd write a column for his magazine GreenPrints. I didn't miss a beat -- my next column came out in GreenPrints just after my last one in Organic Gardening."

Now McGrath has spent seven years doing his radio show, You Bet Your Garden, which is broadcast across 50 stations nationwide and on Sirius. He still writes for GreenPrints, and manages to publish a book every couple of years. You Bet Your Tomatoes has just been reissued, and Mike McGrath's Book of Compost continues to sell well. His new book, just out from Quirk Books, the publisher responsible for Pride and Prejudice and Zombies and the Worst-Case Scenario Handbook, is -- well, not quite a book. "It's a box," McGrath said. "It's a book in a box." Called Kitchen Garden Box: Save and Sow the Seeds of Your Favorite Vegetables, it's a boxed set of instructional cards and seed-saving envelopes designed to help vegetable gardeners plan a garden, then save and store seeds.

"People have not been this interested in growing their own food since the back-to-the-land movement," he told me, "so this is a huge opportunity for organic gardening. But there is less reliable information out there than ever. Nature doesn't have a marketing budget or a PR machine."

McGrath sees himself as an activist, advocating for the pleasures and benefits of organic gardening. "The more time people spend in front of the computer -- this false, unreal world of social networking and the Internet -- the more they need to escape into the green. People really need a garden -- a natural, green growing place, where they can recharge their batteries and remind themselves what is truly real."

He's coming to Humboldt to spread the gospel this weekend. As the keynote speaker for the Organic Planet Festival in Eureka on Sunday, he's planning to shake things up. He wouldn't give me too many specifics about the talk he's got planned, but this is what I managed to get out of him: "I'm going to do something unique -- a fairly dramatic call to action, with the knowledge that I'm in Humboldt County, where everybody in the audience is already eco-wearing, Prius-driving, hippie-dippie perfect. I've got a call to action to challenge people in the audience to stretch, but in a very entertaining way. I think I'm going to present organic gardening as a hybrid of how Richard Pryor and Robin Williams would present it."

I jotted all that down. Organic gardening ... Richard Pryor ... got it.

"It'll be more like a prizefight than a speech," he said.

Prizefight? "I want to shake things up," he said. "In a place like Humboldt, it's easy to deceive yourself into thinking we live in a clean, green world and everybody is doing organics. Of course, it is getting better. Look at Readers Digest. They used to be the Dick Cheney of the gardening world, and now they're publishing books on how to garden organically. That's the ultimate victory. But those are hard-won victories and there's lots more work to do. I want to remind people to stay out there."

Mike McGrath is nothing if not surprising, and as it turns out, you'll have three opportunities to be surprised over the weekend. Drop by Pierson's on Saturday, Aug. 29, from 10-11 a.m. for a workshop on composting, or head over to Eureka Natural Foods that afternoon for a meet and greet from 1-2:30. Then on Sunday he's the Organic Planet Festival's keynote speaker, going onstage at 3 p.m. and then signing books afterwards at the Pierson's tent.

Also on the schedule for Sunday is Rita Jacinto of Flying Blue Dog Farm and Nursery, who will explain ways to grow and use herbs at 10:45 a.m.; Eddie Tanner, author of The Humboldt Kitchen Gardener, demonstrating how to prepare new beds at 11:30 a.m., and then at 12:15 p.m. Gisele Schoniger of Kellogg Garden Supply will discuss how to build up beneficial organisms in the soil. At 1 p.m. Jeff Anderson of Mycorrhizal Applications, Inc. will talk about mycorrhizal fungi in a workshop called "The Secret Beneath Your Feet: The Original World-Wide Web." Then McGrath takes the stage for his prizefight.

The festival, sponsored by Californians for Alternatives to Toxics (CATS), happens on Sunday from 10:30 a.m.-7:30 p.m. at Eureka's Halvorsen Park at the foot of L Street on the waterfront. Tickets are $12 in advance or $15 at the gate. Visit organicplanetfestival.org for details.