Remove Powdery Mildew on Clones?

Not WPM............WPM only affects leaves. The white on the plugs is just fertilizer salts, or minerals from your water supply. No need to do anything, plant them asap and they will be fine.

Good job on the clones, they look great and I love using those plugs myself. I do not think you have WPM, so you should be ok here. Roots look nice and healthy. Get them in some media soon and let them take off! Hope this helps.

heh, that looks a bit dry.. is it possible it's just solids from evaporation? usually clones don't have a lot of fertilizer applied, but just in case... worth a thought.

You've got some sort of growth on the substrate. This happens with clones because the plugs stay moist for extended period of times. if it is wpm, it must not be the type that grows on marijuana plants -- supposedly WPM is highly specific in that way. variants of it only attack 1 or selective species. This is why you'll see it on one plant in a garden but not the different plants adjacent. At this stage it's already propagating and spreading, so it'd be on the leaves if it was dangerous at this point for sure. Bury it on transplant, maybe knock off that top layer as you transplant etc. I've never had a problem for this sort of thing, so far. I usually knock off that top layer and make sure it gets slightly buried to keep roots at proper depth and not exposed to light. If concerned, isolate it in the meantime and for a week or two after transplant. A colony of WPM only takes 3-5 days to form and start producing spores. I doubt you have a problem. like i said, it'd already have spread if it were the fungus you have to worry about. The WPM that attacks marijuana has no cure. Even if the surface is 'washed off' the mycelium network exists under the cuticle or whatever the top layers are called of leaf/stem material. It'll grow back. It'll contaminate smoke/extracts regardless of how clean it is on the outside at the moment of spraying it and shortly after. you can prune off infected parts and hope you caught it before it spread. Anything that's truly effective is also very toxic. home remedies and other nonsense including the Cornell formula, milk sprays, h2o2, potassium carbonate, and others are 100% useless nonsense. Spraying plants with this shit will only spread the wpm to the stems and underneath the buds as it drips down. it'll make it worse even if it 'looks' cleaner the first 24-36 hours afterward. WPM is mostly self-inflicted. Control your RH and temps and you'll be fine. If you consistently hit the dewpoint, which is not difficult when lights go out and temps drip precipitously, you will likely grow wpm at some point. Getting daily condensation is bad. If you happen to run at 32C or a tad higher normal RH levels equate to a dewpoint in the low 70s or higher (lol, my dewpoint chart is C and my themostate is F). that's very easy to hit after lights turn off in any garden with slightly higher daytime temps. A dewpoint chart is a useful reference. A wireless temp/rh probe is nice too.