With the aim of estimating the optimum plot size and verify the behavior of the experimental precision in different plot sizes and shapes to consider the production of snap beans, the following white experiments were conducted: 1) in a greenhouse during the autumn and winter; 2) in a poly-tunnel during the autumn and winter; 3) in an unprotected environment during the autumn and winter; 4) in a poly-tunnel during the spring and summer; and 5) in an unprotected environment during the spring and summer. The fresh pod mass was measured for pairs of plants. For each different plot size (X) the variation and its relation to X was estimated. The optimum plot size was estimated using the method of maximum modified curvature, and the significant minimum differences between averages were estimated using the Hathaway method. Analyze the total fresh biomass of pods reduces variability in experiments with green beans and optimum plot size recommended for this crop is 16 plants in a greenhouse for experiments and plans for 12 tunnel experiments and experiments in non-protected.
