Fertilization in tobacco cropping is a prerequisite for high yield and quality production. Potassium plays a key role in determining some important quality parameters such as leaf color, texture, hygroscopic properties, combustibility, sugar and alkaloid contents. This role is well documented, but with the development of drip irrigation and fertigation, more information is required. Of particular interest are the effect of fertilizer grades and timing of application since the main benefit of fertigation is the ability to adapt mineral nutrition to the instant requirements of the plant. Wrappers or "capas", the large leaves covering the cigar, are increasingly being cropped under drip irrigation. In order to complete the information available to producers, a series of experiments was carried out from 1997 to 2001 comparing different potash grades and application programs in the main tobacco production area in Cuba. The experiment on black tobacco compared fertigation programs during 3 or 4 weeks to a basal dressing control. Two types of potash fertilizers were tested, potassium sulfate and potassium nitrate. Results clearly demonstrate the benefit of fertigation compared to traditional cropping. The detrimental effect of late application of nitrogen is also clearly established. This leads to the conclusion that in order to produce quality wrappers nitrogen should be applied no later than 21 days after transplanting. Potassium sulfate can be used up to 35 days after transplanting in order to improve maturation and combustibility of the leaf. In 2001, a similar experiment was carried out in the Agricultural Research Center of Aspach in France. This experiment on Virginia and black tobacco confirms the results obtained in Cuba.