  We put forward a new phenomenological method for calculating the slope of
radial trajectories from values of ground states and vacuum condensates. The
method is based on a large-$N_c$ extension of borelized spectral sum rules. The
approach is applied to the light non-strange vector, axial, and scalar mesons.
The extracted values of slopes proved to be approximately universal and are in
the interval $1.4\pm0.1$ GeV$^2$. As a by-product, the given method leads to
prediction of the second radial trajectory with ground state mass lying near
0.6 GeV.
