Photographed by Anna-Alexia Basile for Lonny.
1. Add all the dry ingredients to a bowl. This includes the sea salt, Epsom salt, calendula petals, peppermint leaves and lemon verbena leaves.

2. Pour the eucalyptus, peppermint and lavender essential oils over the dry ingredients and stir.

3. Transfer to glass jars to store. Or if you don’t want to get petals in your tub, you can opt for muslin bags instead. Just fill each bag with one cup of the mixture. There isn’t so much plant material that the bags are necessary, but they’re a tidier option if you want extra protection for your bath or drain.