To mark it's third year, the "Eat Local Challenge" is expanding from a week-long initiative to one that spans the whole month of September.

The aim is to encourage thousands of people to build a more sustainable, secure, and healthy local food system. And to help everyone through the month, there are weekly mini-challenges:

• Week 1 (Sept. 5-8): Education: Learn about Hawai'i's local food system.

• Week 2 (Sept. 12-16): Grow your own: Plant/harvest local foods at home and in the community.

• Week 3 (Sept. 19-23): Choose local: Find local food at restaurants and markets.

• Week 4 (Sept. 26-30): Eat strictly local: Strive to eat only locally grown foods for one week

To advance personal, corporate, and policy change in favor of sustainability, there are over 40 partners on Oahu, plus additional partners on Maui, Kauai, and the Big Island. Among them are Soul in Kaimuki (offering locally grown menu items in partnership with Yelp Honolulu), Zippy's (offering a "Local Loco Moco with Nalo Greens"), and Eat Honolulu in Iwilei (with local beef, local salad, and kale). Foodland is offering an "Eat Local Incentive," recipes, videos, and farm tours.

The challenge will kick off tomorrow, Wednesday, Aug. 31, with "Ag in the City" at the Honolulu Farmers' Market, which takes place on front lawn of the Neal S. Blaisdell Center Concert Hall. Organized by the city and the Hawaii Farm Bureau Federation, "Ag in the City" will feature a collaboration between young farmers and young chefs, including Ed Kenney, Mark Noguchi, Andrew Le, Sean Priester and Kele Smith. The program begins at 4:30 p.m.

It's the third week of September when the "Eat Local Challenge" will be most visible, as participating local restaurants highlight the locally-grown products on their menu. A favorite stop for me has been Big City Diner., which this year will be showcasing fresh catch-of-the-week fish with oyster cream sauce and tomato watercress salad.

To participate, you can "Take the Challenge" at the Kanu Hawaii website, or signal your commitment by SMS. Just send your name and e-mail address in a text message to 1-801-901-3555. Kanu Hawaii will send you special deals and tips on how to eat local.

You can also connect with Kanu Hawaii on Twitter and on Facebook.

The "Eat Local Challenge" is a presentation of Kanu Hawaii, in partnership with the Kokua Hawaii Foundation, and HICORE 5210. Sponsors include Kaiser Permanente and The Ulupono Initiative.