If you haven't yet bought any locally grown tomatoes, you'd best hurry: The season started late and is primed to end early, a result of rotten spring weather.

By late June, local farmers are usually so flush with fat, handsome tomatoes that GrowFood Carolina confidently advised Mixson Market to schedule its annual tomato harvest celebration for the last weekend of the month. But this year, the produce distributor had to scramble to come up with enough good-sized 'maters for the sampling stations.

Itty-bitty heirlooms became a familiar sight on restaurant plates this summer, with chefs plating up split baby tomatoes alongside shrimp, flounder and the remainder of the season's expected bounty (for an illustrated examples, check out this week's Sum of its Parts on Page D4.) Although the tomatoes were tasty, Lowcountry growers are understandably grumpy about the crop's poor performance and delayed harvest.

But seasonality is what makes tomatoes special. Most tomato fans agree that nothing quite rivals the distinctly summertime sensation of eating a juicy tomato, still warm from the vine, sliced and salted or - better still - pressed between two slices of white bread spread with mayonnaise.

But that's the wishy-washy stuff. For seven facts as hard as an unripe tomato, read on:

1. Sixteenth-century European explorers brought tomatoes back from Mexico, where the fruit had migrated from its native South America. But their countrymen didn't immediately hail them for the find: Because the tomato is a member of the nightshade family, it was widely considered poisonous. Although poor people probably took a chance on the plant, it took at least a century for the tomato to become a common ingredient in Western cooking.

2. Gardeners who annually agonize over how to use up all of their tomatoes probably don't need tips from Charles Wilber, who set a world record for coaxing 1,368 pounds of fruit from four plants. But according to the green thumb-holder's how-to book, the secrets to high yield include plump seeds, compost made from kudzu and chicken droppings, mulch and pond water.

3. Thomas Jefferson famously shipped tomato seeds home from Paris, but tomatoes had already reached the South, most likely via the Caribbean. Andrew Smith, author of "The Tomato in America," credits a traveling herbalist with the first British North American tomato sighting: He reported coming across a South Carolina tomato in 1710.

4. A medium tomato doesn't have many calories, clocking in at a mere 35. But the same tomato has as much fiber as a slice of whole-wheat bread, one-third of the daily recommended vitamin C allowance and 10 times as much lycopene as a red pepper. Tomato consumption has been linked with improved heart health, reduced obesity risk and stronger bones.

5. There are about 7,500 varieties of tomatoes, grouped in seven general categories, including beefsteak tomatoes, plum tomatoes, cherry tomatoes and grape tomatoes, which a Florida grower started planting in 1996 after receiving seeds from a Taiwanese friend. "With their crimson color, oval shape and size - slightly smaller than cherry tomatoes - they were like nothing else on the market," the Associated Press reported.

6. Ninety percent of winter tomatoes in the U.S. come from Florida fields, where working conditions were long horrific. According to Barry Estabrook's 2011 "Tomatoland," child labor and minimum wage laws were routinely flouted, and slavery tolerated. But the Coalition of Immokalee Workers' campaign for major fast food restaurants and supermarket chains to pay an extra penny per pound for tomatoes has resulted in an astounding turnaround: "Now the tomato fields in Immokalee are probably the best working environment in American agriculture," a Pardee RAND graduate school dean told The New York Times in April. The Coalition is now targeting holdouts Wendy's and Publix.

7. Canning tomatoes, whether whole, chopped or pureed, is possibly the most popular way to extend the summer fruit's usefulness. But other preservation options include oven-drying and freezing. The upshot of the latter method, which consists of sliding tomatoes into a plastic bag, is the tomatoes' skins peel right off after thawing.