In article ,
"Rod Craddock" writes:
|
| As for the 'black spot', some nutrient deficiencies on roses
| particularly Potassium can look a bit like black spot, so I'm guessing
| your brew at least partially corrected that.

It could also work similarly to milk. My guess is that the nutrients
in milk (and perhaps liquid compost) encourage bacteria or other fungi,
which then consume the black spot. But that is a wild hypothesis :-)


Regards,
Nick Maclaren.