How long can this mixture last?

[Rehab350]

Yesterday I boiled peppermint and refrigerated it in a mister bottle, today I added rose water and few drops of olive oil. My hair loves it.
Now my issue is that I can not use all of the mixture, not even half of it. It may take days to finish. Can I still use it if I keep it in the refrigerator. and for how long can I keep it there?

[Rehab350]

I am thinking of adding my silicone conditioner to this mixture. What do you think of this idea? Does this change durability of the mix

[meteor]

Since this is a water-based mixture without adequate preservatives, you should try to use it up fast (and keep it in the fridge in the meantime), say 5 - 7 days. But always smell it before use and look out for color/texture changes, just in case.
If you can't use it up that fast, just freeze it. You could freeze it in portions, like ice cubes, to make it easy to thaw a bit of the mixture - for each use.

[Arctic]

Yeah Meteor already said it, although I would advice keeping it even shorter while. Just few days, maybe max 3. Germs start growing in your mixture as soon as it's done, you don't want that near your scalp. Adding conditioner won't help it to keep longer.

The icecube idea is mighty fine, I'd go with that route.