This paper explores the different types and characteristics of preschool children's explanations of plant growth and rain formation. The children's explanations were categorized as naturalistic, non-naturalistic, or synthetic, i.e., explanations containing both naturalistic and non-naturalistic parts. In regards to plant growth the children tended to rely on synthetic or on naturalistic explanations, which involved direct and indirect agents (such as water, a person, fertilizers, roots) enabling the plant to grow. Non-naturalistic explanations of plant growth, or the non-naturalistic parts of synthetic explanations, were mainly animistic (anthropomorphic). In the case of rain formation the children most frequently used non-naturalistic explanations, which were mainly teleological or metaphysical. The naturalistic explanations recorded on rain formation, as well as the naturalistic parts of synthetic explanations tended to have a non-agentive character, i.e., children considered rainwater as preexisting in containers such as the clouds. Overall, the explanations recorded about plant growth tended to be more complex than the ones for rain formation. It is suggested that science activities designed for preschool children should take into account the types and characteristics of their explanations in order to select which phenomena are appropriate for this age group, and aim at fostering the children's ability at formulating naturalistic explanations.