By Roger
Oxfordshire,
United Kingdom 
Could someone tell me why my Violas have got this white mildew all over the leaves , they are in my greenhouse at the moment is this too warm for them ?
17 Sep, 2011
Answers
Powdery mildew can be down to exposure to humidity and poor air circulation.
17 Sep, 2011
Thanks for your replies I have now put them out side
17 Sep, 2011
They should improve now.
17 Sep, 2011
Um, I'd spray them, frankly, with a fungicide suitable for mildew. Mine have mildew currently and they are outside... you could also try the 1 part full fat milk to 9 parts water trick and spray with that, but I'd use a fungicide.
17 Sep, 2011
I would suspect that is the reason and perhaps too humid as well. Could they go outside after hardening off? I think they would do better outdoors.
17 Sep, 2011