As Mike pointed out, whatever ends up in your water butt is not simply what has fallen from the sky, it's all the spores that only blow around at or near ground level along with everything else at that level including creatures too.graham wrote:Forgive me - but I cannot see how that makes for good practice. Unless someone or something is adding to the water butt then everything in it, good and bad, came from the sky with the rain.
If you hold up a glass and collect rain directly from the sky, it'll be far less harmful for your seedlings than water that has been festering in a water butt for however many days or weeks. Your water butt is a breeding ground for all sorts of moulds and fungi that wont be present when collected directly from the sky.
It's fine for adult plants because they can take it, but using waterbutt water for seedlings in a baggy environment is probably one of the most effective ways of ensuring they all die, fresh rainwater much less so, and tap water or sterilised water, very often not at all.
Mike suggested looking in your waterbutt for evidence of this, here's a question to throw on top of that, would you be happy to drink rainwater fresh from the sky? I know it wouldn't bother me because the chance of harm is pretty much zero. Would you be willing to drink water from your waterbutt? I know I wouldn't because there's a remote chance if it's been in there long enough that you could ingest a fatal dose of legionella.
