It's a question newcomers often ask: Why, in sunny Hawai'i, is it so difficult to find good tomatoes, and why are most of the tomatoes we eat not grown locally?

Tomato grower Jeanne Vana of North Shore Farms summarizes the problem in three words: weather, disease, pests.

Of the various fungi, blights, viruses, wilts and bugs that plague tomatoes, Steve Gunn, deputy director of the state Department of Agriculture's Agricultural Statistics Service Branch, said, "It's paradise for them, too."

And a week of cloudy skies and/or heavy rain can bring production on a particular farm down to zero, said Genevieve Pagdilao of Kawamata Farms in Kamuela on the Big Island. The tomatoes cease to ripen and the moisture encourages rot.

The tomato spotted wilt virus virtually shut down Maui tomato production a few years back. Some O'ahu farms are all but out of product right now because of recent rains, though Vana's 10 acres in Waialua were unaffected.

Tomatoes are a middle-size agricultural business here. In 2003, the last year for which complete statistics are available, there were 560 harvested acres of tomatoes grown in Hawai'i, a total of 17,500,000 pounds, Gunn said.

However, Vana pointed out that there is no tomato growers' association, and there isn't anyone in the agriculture department or at the university who specializes in tomato production, meaning farmers have to work through their own learning curve.

Pagdilao of Kawamata Farms, which grows beefsteaks on four acres in Kamuela, said some practices that are standard in other tomato-growing areas are cost-prohibitive here or difficult because of state regulations. These include use of glass greenhouses (which would have to be earthquake-proof and equipped with climate control to keep from getting too hot) and biological controls, which means using good bugs to defeat bad pests (difficult here because of regulations on importing insects and other animals).

Most tomatoes here are grown in controlled conditions: in screened greenhouses or hydroponically. All this infrastructure adds to expense, said Gunn. Farmers employ crop rotation and a variety of sanitation practices to prevent the spread of disease — and this takes time, labor and money, too, Vana said.

The next factor in the tomato equation is flavor, a function of variety and ripeness. Commercial varieties have been developed to promote uniform appearance and shelf life. (One factor in the development of the round, shoulderless tomato was the waste created for fast-food restaurants by unevenly shaped fruit; McDonald's gets a tomato that fits a bun, we get flavorless red baseballs.)

Vana's notoriously lumpy, bumpy, oddly colored heirloom tomatoes are grown from old-fashioned garden varieties, which she has found have more flavor.

Tomatoes do not develop full flavor and the right sugar balance unless they are allowed to fully ripen on the plant and in the light. But allowing tomatoes to sit on the vine shortens their shelf life after picking. Large farms often pick tomatoes green and use gases to bring on red color; such tomatoes can stand up to several days of shipping and handling and still give the consumer a week in the refrigerator.

Vana says instead of vine-ripened, she calls her tomatoes "picked-ripe." She says imported tomatoes you see in grocery stores that are sold on the vine can't be harvested ripe; if they were, they wouldn't stay on the vine.

Every year, restaurateur Peter Merriman, an advocate of small farms and quality produce, hosts a tomato-tasting competition at his Merriman's Restaurant in Waimea on the Big Island. And every year, the competition is won by small growers like Lokelani Farms, Sunrise and Big Wave. Most of these high-quality, really ripe and tasty tomatoes aren't widely available; they're sold at farmers markets, directly to restaurants and occasionally through small outlets.

Is there a way to judge a tomato's flavor by sight? Not really — even a vine-ripened heirloom can be disappointingly watery, bland or over the hill on occasion.

However, in general, the odder-shaped the tomato, the better flavor it will have, because it's probably a garden variety that hasn't had the flavor bred out of it. In general, the best tomatoes don't make it to conventional supermarkets, or they go only to supermarkets in more affluent neighborhoods where the focus is on "gourmet" ingredients. Merriman, who lives on Maui, says he finds the best tomatoes in the health-food store. And in general, a good tomato is a bit tender to the touch and, held to the nose, has that distinct peppery-sweet tomato fragrance.

At Safeway Beretania, shopper Merrilee Lynch looked over the tomato offerings, and put a carton of small, California-grown grape tomatoes in her shopping cart."I pretty much only buy grapes and cherries anymore," she said. She is generally disappointed in the quality of the imported beefsteaks but finds local heirloom tomatoes too expensive.

Merriman said labor costs are a key issue. He points out that Lokelani Farm in Waimea grows only enough tomatoes to supply his restaurant. "That's a lot of work for just one restaurant," he said. "I think it comes down to how much people are willing to pay — a really sweet, vine-ripened tomato costs a lot to produce."