Viewing post #3005871 by Murky

I found a recipe for making your own at The Spruce, but it also says:

A homemade solution of pyrethrin pesticide has a shelf life of only 12 to 24 hours, so any that is leftover after application will need to be discarded. Thus, it's best to grind and mix the pesticide in relatively small amounts as you need it.

If it's not because of their recipe using crushed flower petals, maybe that's the only issue and that 10% includes some preservatives to make the shelf life longer?