here is the thing, I'm a new gardener with a newly planted garden. Seems I have been a bit over zealous in the watering department. Powdery mildew appeared on the ajuga. I did a Google search and discovered adding baking soda to tap water in a spray bottle then misting the affected plants, waiting 12 hours and misting again stops the powdery mildew. It has been 4 days now and no mildew has re-appeared. Does everybody know this trick?
Plants mildew when the roots are dry and the leaves are damp. This is why we see it here on the Pacific Slope during the summer dry season, when watering often has not been kept up with or undertaken at all, the soil becoming dust dry while the leaves may be dampened by fogs or dew. Ajuga is a moisture loving plant and needs to be kept watered unless growing on a retentive soil in a shaded position where it can squeak by during the annual summer drought. I planted a couple one gallon pot size ajuga recently and had one of them wilt while I was away, despite having been watered in at planting - no doubt due to it being planted with intact potting soil rootballs. When there is a marked difference between the texture of the soil inside the rootball (or liberally amended planting hole) and the existing soil around the rootball (or planting hole) movement of water into and out of the rootball (or planting hole) is adversely affected. In the case of my ajuga being planted with coarse soilless potting mix on the roots into a much finer textured actual soil this latter material will have a greater attraction for water than the potting soil, resulting in water tending to move out of the rootball instead of into it.
