what causes white dusty spots on the top of my plant leaves
this is a indoor garden
Certified GKH Gardening Expert
It could be water spots. If you water from above the plants, the water on the leaves can dry and leave a dusty residue which is the minerals in the water.
If the spots are more fuzzy like cotton, it could be mealybugs. This article will help you with those: https://www.gardeningknowhow.com/plant-problems/pests/mealybugs-white-residue-on-plants-leaves.htm