The growth of the foliar area is mainly for the plant development, particularly in Musaceae, which get sizes relatively bigger as compared to the other vegetable species. An estimate of the final behavior of the foliar area is made for a banana species, from experimental measurements carried out from the beginning of the plant development up to four months, considered in fifteen -day stages, using a model that describes the trend of final foliar growth which the plant can reach in the stage after the last experimental measurement. The first measurement is considered to run the model with each of the subsequent measurements. The model is selected in the class of functions of the type second order rational fractions, from which those that have a non-sigmoid geometric behavior are discarded, imposing conditions on the coefficients, among which are subsequently selected from the experimental data, those that they accurately represent the process.