  We study homogeneous nucleation in the two-dimensional $q-$state Potts model
for $q=3,5,10,20$ and ferromagnetic couplings $J_{ij} \propto \Theta (R -
|i-j|)$, by means of Monte Carlo simulations employing heat bath dynamics.
Metastability is induced in the low temperature phase through an instantaneous
quench of the magnetic field coupled to one of the $q$ spin states. The quench
depth is adjusted, depending on the value of temperature $T$, interaction range
$R$, and number of states $q$, in such a way that a constant nucleation time is
always obtained. In this setup we analyze the crossover between the classical
compact droplet regime occurring in presence of short range interactions $R
\sim 1$, and the long-range regime $R\gg 1$ where the properties of nucleation
are influenced by the presence of a mean-field spinodal singularity. We
evaluate the metastable susceptibility of the order parameter as well as
various critical droplet properties, which along with the evolution of the
quench depth as a function of $q,T$ and $R$, are then compared with the field
theoretical predictions valid in the large $R$ limit in order to find the onset
of spinodal-assisted nucleation. We find that, with a mild dependence on the
values of $q$ and $T$ considered, spinodal scaling holds for interaction ranges
$R\gtrsim 8-10$, and that signatures of the presence of a pseudo-spinodal are
already visible for remarkably small interaction ranges $R\sim 4-5$. The
influence of spinodal singularities on the occurrence of multi-step nucleation
is also discussed.
