In nearly every garden, there's a magical spot where plants thrive. Here, roses give more fragrance, strawberries grow sweeter, daylilies bloom sooner.

It's the same way with wine grapes. Certain locales have conditions that create delicious wines year after year; nowhere is this more evident than in California's Napa Valley, where wines made from Cabernet Sauvignon grapes are among the best in the world. As with any garden, it starts with the soil.

And while Napa's soil isn't the only factor that makes the area's Cabs shine, the good earth is key. According to geologist Jonathan Swinchatt, one of the main reasons vines in Napa Valley produce flavorful grapes is because of the surrounding mountains: Over time, wind, rain, and erosion have swept down an almost ideal mixture of gravel, clay, and sand.

"The vines can get the water and minerals they need from the soil in the quantities they need," says Swinchatt. The soil also dries out quickly, which promotes better flavor because grapes, like tomatoes, do best on a lean diet. Also, grape growers have found that reducing irrigation almost to the wilting point during the growing season makes for the best flavor development. That's why they prize Napa Valley soil's ability to dry out quickly.

Where the soil isn't perfect, vineyard managers bring it as close to the Napa ideal as they can by savvy practices such as adding drainage systems and boosting minerals. In the last two decades, many vineyards have been replanted to take advantage of new disease-resistant, better-tasting varieties of grapes, which also gave growers the opportunity to make changes in their land.

"The last time we replanted our grapevines, we added 10 tons of compost per acre to the soil," said Bruce Cakebread, president of Cakebread Cellars, whose family has been making wine in Napa for more than 30 years. The family also took the opportunity to plant their grapes in soils where they knew each type would grow best, with Cab in the lightest soil, Merlot in the soil with a bit of clay, and whites in the heavier soil.

Opening a bottle of a good Cab is like opening a treasure chest: Your mouth fills with layer after layer of flavor as you drink-an initial burst of plums or cherries followed by the hint of herbs such as mint. Many have an aroma reminiscent of tobacco or cedar. Napa's Cabernets also have lots of texture- these opulent wines are the complete opposite of thin and watery.