Combine the ingredients of your homemade laundry detergent in a large, lidded container. Common ingredients for homemade powdered laundry detergent include borax, washing soda and bar soap that has been grated. Mix the laundry soap well with a large spoon and set aside.
Add 10 drops of lemongrass essential oil for every two cups of laundry detergent by squeezing the bottle directly into the container of laundry detergent. This ratio will add a light, subtle scent to your laundry. Mix the oil into the detergent using a large spoon.
Add an additional 10 drops for every two cups of laundry detergent if you want your laundry to have a stronger lemongrass scent. Do not use more than 20 drops for every two cups of detergent or the smell will be overpowering.