Composting and Soil chemistry workshops
We have been teaching our composting and soil science lessons to all South End School students in Term 1. The weather has been great for teaching in the outdoor classroom. We use red cabbage water as an indicator to show the pH of different household items and composting ingredients. The vinegar and citrus juices turn the cabbage water from violet to bright pink indicating a strong acid and baking soda, wood ash and lime turn the cabbage water from pH neutral violet to green or yellow indicating strong alkali. The students think about how the grey water from the washing machine is strong alkali and not good for the garden and how too much citrus peel in the compost could make a very acidic compost … perhaps adding a little wood ash can balance the pH?