The quantitative analysis of the growth has been used by plant researchers trying to explain the differences in the growth, the genetic or the result of changes in the environment. The objective of this work was to evaluate the growth of the parameters in the Tagetes patula crop, inside and outside the greenhouse. The experiment was carried in the experimental area of the Department of Natural Resources - Section Environmental Sciences of the Faculdade de Ciências Agronômicas, UNESP, Botucatu-SP, 21/05/02 to 09/08/02. The experimental area was constituted of two areas of 280m2, being one in the field condition and the other one in greenhouse “arch type” , with polyethylene low density (LDPE) covering, light difusor, with 150m of thickness, and polypropylene screen with 50% of solar radiation reduction in the lateral. The results showed that inside the greenhouse the values of the average height of the plants, average leaf number for plant, foliar area and average index of foliar area had been greater than in the field condition. The length of the roots and the number of floral buttons had not presented significant differences between the two conditions of culture. The plants of the greenhouse had presented flowers of better quality, evidenced the positive influence of the greenhouse in this parameter.