My rosemary is not looking good. I have it in a pot sitting in a sunny window. I used miracle grow potting soil. It is not over watered (once a week). It has been in pot about 2 months. It has grayish coating in leaves. Limp looking.
Certified GKH Gardening Expert
That appears to be powdery mildew. This can be fixed by spraying with neem oil. Just be sure to wash it off before you use it. I don't ever recommend using miraclegro on anything that you intend to consume. It is usually a little overbearing to plants like this anyway. I recommend a good organic potting mix, or adding organic compost to a decent potting mix.
This article will give you more information on growing this: https://www.gardeningknowhow.com/edible/herbs/rosemary/rosemary-grown-in-containers.htm