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Stained patio after fertiliser

Hi everyone.

I administered weed feed and moss killer to my grass yesterday and today I've noticed rust coloured footprints on my patio.


Removing the stain is one problem, but how long is it before its ok to walk from grass onto patio without stressing about more stains?

Forecast says rain on and off all week (hence why I put the feed on the lawn in the first place) so waiting for dry grass before walking on the grass (then patio) could mean our garden is out of bounds for weeks!



  • LoxleyLoxley Posts: 5,399
    Oh bugger! Would have thought it would wash into the soil after a couple of days of rain.
  • How much have you actually spread? A normal dose should sink in a day or so. Maybe avoid in the future a weed treatment that's based on iron which is presumably why it colours red. 
    To Plant a Garden is to Believe in Tomorrow
  • Pete.8Pete.8 Posts: 10,897
    It's the moss killer element of weed and feed that contains iron which causes the staining.
    It is rust basically
    Once washed-in it won't be as bad, but best to stay off it if you can for a while.
    The stains my come out with a brush and soapy water or you may need a specialist rust remover depending on what your patio is made of

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • Sigh. Im so annoyed with myself. I've used this treatment many times over the years, and never had this issue. But we had a new patio put in this summer, and its a dark grey colour. 

    Double sigh.

    I'm scared of walking on the grass now in case I make the problem worse. 


  • Moss killer contains iron sulphate (well, most do) which is probably why your patio has turned red - you may have put too much on? The base of my conifer or acer pots sometimes does the same as I feed them with iron. 
    Let the patio dry out - if you can - then pressure wash off.
    Ironically sometimes adding iron to kill moss can exacerbate the problem - moss likes poorly drained acidic soil. I mostly scarify, aerate, then add lime to lawns at this time of year. It should be all leached into the soil after a week though, I would suggest.
  • FairygirlFairygirl Posts: 53,924
    Yes - the iron is the problem. Can you hose it down, or  use a bit of fairy liquid and a brush?
    Best stay off the grass @janiner until it's been well washed through. Infuriating for you though. 
    If you need to go on the grass - for doing washing or anything - you could put a few planks down, or have an old pair of shoes you can leave at the door. 
    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • LynLyn Posts: 22,852
    We did the same, it will go, the rain we’ve just had would wash anything away.
    i can’t remember how long it took but it definitely did vanish. 
    Gardening on the wild, windy west side of Dartmoor. 

  • KT53KT53 Posts: 8,458
    It doesn't need to be any kind of overdose to create the problem.  I've experienced the same over the years.  The marks do fade away.
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