Joshua McNichols, author of "The Urban Farm Handbook"

You may have noticed them as you drive around your Seattle neighborhood. They look like garage sales. But on closer inspection, you see those boxes aren't full of old crappy McDonald's toys -- but heirloom tomatoes! That's because this is the season of the "bulk produce buy."

A bulk produce buy is a new way to get local produce at wholesale prices in bulk. It emerged from the strong relationships developing between urban foodies and rural farmers.

Here's how most bulk produce buys work:

Someone -- an unpaid organizer -- develops a relationship with a farmer. They learn what that farmer grows and when it ripens. Around peak season, they find out when the farmer's coming over the Cascades with a load. In the case of tomatoes, buys often pigggyback on a load brought over for Whole Foods. The organizer offers to find homes for up to 2,000 pounds more. The farmers are happy for the extra volume –- after all, the grocery store can't take a whole trailer-full of tomatoes.

The organizer makes a Google spreadsheet, with prices per pound clearly displayed and slots for people to place their orders. In the case of tomatoes, we buy them at half or even a quarter of the retail price. The organizer posts an invitation at the Seattle Farm Co-op's Yahoo Group message board (http://groups.yahoo.com/group/seattlefarmcoop/).

Buyers agree to pick up their produce within a limited window. The organizer often arranges to be at home for a whole day, so that people can pick up. Sometimes the delivery date changes based on the farmers needs, so there's often last minute networking on the website, with people arranging to pick up each others' orders.

There's some risk in the system. The organizers must pay the farmer upon delivery, but the organizer is not repaid until people drift in to pick up their orders over the next day or so. Generally, the organizer doesn't mark up the produce, so there's no financial cushion if someone doesn't show up for their produce. And what would happen to the farmer if an organizer refused a load?

Those risks explain why organizers tend to work with the same farmer year after year. Over that time, trust develops.

If you're interested in getting in on group buys, join the Yahoo group and watch. Buys for winter storage squashes, apples and pears should post in the next few weeks.

Our farmers tell us these buys are an exciting new market for them. We know they made a big difference for our favorite tomato farmer, Skeeter, last year. So much so that he's begun acting as a social hub, helping the farmers around him access our market. Just last week, a farmer called him, saying desperately, “I have a thousand pounds of organic heirloom tomatoes I'm going to have to dump!" Skeeter called us, and our network swung into action. An organizer forked over the money, and within 24 hours we had sold them all.

That's how I ended up with 120 pounds of amazing heirloom tomatoes on my back porch. I'm staying up until midnight almost every night canning, during one of the most important work weeks of my life. But I'd be lying if I didn't admit I love it. I love being a part of this network. I love knowing my farmer, and knowing that I'm as useful to him as his tomatoes are to me.