Tobacco seedlings in Cuba are produced in seedbeds placed in open fields. Since 1995 the introduction of a new system for producing seedlings was initiated using float trays. Three main problems to solve were to define an inexpensive greenhouse for farmers, to produce a substrate with the adequate requirements and to obtain the available fertilization, taking into consideration the characteristics of the float water. Two experiments were conducted to evaluate in one of them the different rates of black peat and rice hull and in the other the different levels of nitrogen in order to know the effect of the main biological characteristics of seedlings. Polystyrene trays of 0.70 x 0.46 m with 247 cells and with a capacity of 27 cm³ for substrate were used. The mixtures of 80% and 20%, and 70% and 30% of black peat and rice hull respectively showed the best results with regard to germination of seeds, seedling height, stem diameter, fresh and dry weight and useful seedlings per tray. The best seedlings were obtained with the level of 50 ppm of N, 60 ppm of P and 50 ppm of K. These results jointly to the design of inexpensive greenhouses allowed to increase in 1997 up to 600 ha transplanted with the float system, which includes 40 % of the total area of shade-grown wrapper tobacco grown in the country.