We compare various evolutionary strategies to determine the ground-state energy of the +_J spin glass. We show that the choice of different evolution laws is less important than a suitable treatment of the "free spins" of the system. At least one combination of these strategies does not give the correct results, but the ground states of the other different strategies coincide. Therefore we are able to extrapolate the infinite-size ground-state energy for the square lattice to -1.401+_0.0015 and for the simple cubic lattice to -1.786+_0.004.