From the Straight Dope website;
First you have to know the three different types of leaf used in making a cigar. Each type requires different seed types, weather and soil conditions, and handling. The filler leaf makes up the bulk of the cigar and provides most of the flavor. There is nearly universal agreement that the best filler leaf in the world comes from a small region of western Cuba. More on that later. Around the filler is the binder leaf, which holds the cigar together. Finally comes the very thin, blemish-free wrapper leaf, which gives the cigar its uniform finished look. The wrapper adds the least weight to the finished product, but has the highest cost, pound-per-pound. Formerly, Indonesia (specifically Sumatra and Java) was the standard for producing fine binders and wrappers, but that region seems to have lost its supremacy. Today the best binders come from the Caribbean (including Cuba) and the best wrappers come from the Caribbean, Cameroon in west Africa, and (you knew I'd get to it) New England.
Between them, Connecticut and Massachusetts exported about $100 million worth of tobacco in 1999, grown mostly in the Connecticut valley. Most of that comes from a relatively small volume of world-class "Connecticut Shade" wrapper leaf, which sells for up to $45 a pound. Such premium brands as Davidoff and Macanudo have used Connecticut Shade wrappers. The variety is named for the highly artificial way it is grown, under the shade of nylon tents. The primary purpose of the tents seems to be to increase the relative humidity and reduce wind.
This brings us to the conditions under which premium cigar tobacco is grown. Producing first-class cigar tobacco is an exacting process. Growing the stuff requires using the right seed and having the right weather and the right soil. And that's only the beginning. After harvest, the leaves have to be cured (dried), fermented and aged properly. The entire process can take up to two years. Tobacco grows fastest with at least 3 or 4 inches of rainfall a month during the growing season and temperatures around 80 F (27 C). However, those conditions are not conducive to optimum quality of cigar tobacco, which requires less rain and somewhat lower temperatures.
What's so special about Cuba? Tobacco is grown in many parts of the island, but the best comes from a small region called Vuelta Abajo tucked between the Sierra de los Órganos and the Golfo de Batabano in the westernmost province, Pinar del Río. This is the wettest region in Cuba, receiving about 60 to 80 inches of rainfall annually. Normally that much rain would be ruinous to tobacco crops, but in Cuba tobacco is grown during the dry season (November-April), when rainfall averages less than 2 inches a month. The unusual combination of moderately moist sandy loam soil, high relative humidity, and moderately low but dependable rainfall during the growing season, together with warm (but not excessively hot) temperatures and little wind, is what makes Vuelta Abajo special. Some experts believe the mineral content of the soil is also important. Connecticut Shade is also grown in sandy loam soil, but in the summer when temperatures are only slightly cooler than in Cuba's dry season. As mentioned above, the tents act to keep humidity high, and also prevent blemishes. Rainfall during the growing season is higher than in Vuelta Abajo, but quality wrapper tobacco requires more rain than quality filler tobacco.
The very high price of wrapper leaf makes it economical to produce under artificial conditions in the Connecticut valley. But growing premium filler and binder cigar tobacco in the U.S. just isn't worth it since conditions are not optimal and prices are lower. Besides the Connecticut Shade wrapper, New England also produces Broadleaf binder, grown in the same areas but from different seed and in direct sun. Binder leaf is also grown in Wisconsin and several other states. Filler leaf is grown in Pennsylvania, Ohio and other states. Large quantities are grown, but quality is not very high and they fetch only one to three dollars per pound. They go into cheap domestic cigars.:2
