We consider the (unique) mild solution u(t,x)u(t,x) of a one-dimensional stochastic heat equation on [0,T]×ℝ driven by time-homogeneous white noise in the Wick–Skorokhod sense. The main result of this paper is the computation of the spatial derivative of u(t,x), denoted by ∂xu(t,x), and its representation as a Feynman–Kac type closed form. The chaos expansion of ∂xu(t,x) makes it possible to find its (optimal) Hölder regularity especially in space.