  We study the spherical collapse model in dark energy cosmologies, in which
dark energy is modelled as a minimally coupled scalar field. We first follow
the standard assumption that dark energy does not cluster on the scales of
interest. Investigating four different popular potentials in detail, we show
that the predictions of the spherical collapse model depend on the potential
used. We also investigate the dependence on the initial conditions. Secondly,
we investigate in how far perturbations in the quintessence field affect the
predictions of the spherical collapse model. In doing so, we assume that the
field collapses along with the dark matter. Although the field is still
subdominant at the time of virialisation, the predictions are different from
the case of a homogeneous dark energy component. This will in particular be
true if the field is non--minimally coupled. We conclude that a better
understanding of the evolution of dark energy in the highly non--linear regime
is needed in order to make predictions using the spherical collapse model in
models with dark energy.
