You do not need a green thumb if you have used coffee grounds!

Because it lowers the ph-level of the soil and thus, it is the perfect fertilizer especially for plants, that prefer a acidic soil. Here, you find a list of such plants.

Used coffee grounds contain phosphorus, which is important for the flower formation. They also contain potassium, which is ensures the stability of the plant. And nitrogen which enhances the growth of the leaves.
You simply need to sprinkle some (dried!) used coffee grounds onto the soil and work them into it. Done. Of course, that also works with tub and indoor plants.

If you have your own compost, you can also use the coffee grounds here. Earthworms like it very much, which again is perfect for the compost.

Used coffee grounds also work as pest control: Snails don’t like it, because they cannot crawl on it, and it is toxic to them. Moreover, coffee grounds neutralize the scents of voles, caterpillars, aphids, flea beetles, and ants – they will look for a new place to live – away from your lettuce and strawberries.

Respect! That is quite an achievement for the fine, brown crumbs, which could have also landed in the trash.