This outdoor experiment walks grades 4-7 homeschoolers through a structured investigation of the effect of different mulches on soil temperature. Students set up five identical containers, each filled with the same soil depth and watered evenly, then apply four different mulches while leaving one container bare as a control. A thermometer probe measures soil temperature at two inches deep at the same time each day for three consecutive days, and results are logged in the provided table alongside an average temperature column. The sheet also includes two open rows for student-chosen mulch types, giving your homeschooler ownership over the variable selection.

This lab fits naturally into a soil science unit study, a gardening-focused Charlotte Mason nature block, or a standalone lesson on environmental variables and heat transfer. By the time your student writes the conclusion, they have practiced forming a hypothesis, controlling variables, recording repeated measurements, and interpreting a multi-day data set. Completing it demonstrates real working knowledge of how ground cover affects heat retention, a concept that connects directly to agriculture, climate, and plant health.