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Fireplace Ash

Hi all, i think i read in a magazine about putting ash from my wood burner on the garden. Does this really offer much to plants generally or do certain plants benefit more?

should i simply sprinkle on the top of the soil?


Many thanks





  • fidgetbonesfidgetbones Posts: 17,441

    Soft fruit such as raspberries, goosegogs and blackcurrants benefit from a sprinkling of wood ash in Spring. Sprinkle it around the base and tickle it in with a hand fork, or cover with a mulch of compost.

  • Ash contains a lot of potash, which will help flowering.

  • Steve 309Steve 309 Posts: 2,753

    Ash from young shoots (like raspberry canes and other prunings) is best as it contains more potassium.  Ash from older wood contains less, but the larger quantity available can make up for that.  It's also alkaline, so beware of using it on azaleas and what have you.

    Best applied in the spring as growth begins, or whever they're making their flower buds for the following year, cos it helps with that; hence it's best for flowers and fruit.  Keep it dry in the meantime.

    Or you can add it to the compost heap.

  • ItalophileItalophile Posts: 1,731

    I add mine to the compost heap. It's extremely water soluble and the benefits are relatively short-lived.

  • Steve 309Steve 309 Posts: 2,753

    The potassium salts/oxides are indeed very soluble, which is the reason for keeping it dry till it's wanted.

    I've never tried this, but it's said to be possible to make soap like they used to from lye (alkali made by dissolving the soluble bits of wood ash in water) and animal fat (such as the stuff that drips out of bangers under the grill).  A good use for two by-products (I tend not to think of 'waste').  The chemistry is straightforward but the resulting product might have an interesting scent!  Anyone tried it?

  • ItalophileItalophile Posts: 1,731

    My mother used to try to make soap. I have no idea what she used but it stank to the heavens and always finished up thrown away. 

    I add the ash to the compost mainly for its bulk. No matter how dry you keep it prior to use, the first decent rain after application washes the goodness away.



  • Steve 309Steve 309 Posts: 2,753

    Indeed.  That's why it's best applied (in small doses I should think) only when it's needed.  But in a covered compost heap there'll be plenty of opportunity for it to be incorporated into other stuff, so that's a good option too.

    Fat and alkali.  The sodium or potassium from the alkali combines with the stearic acid from the fat to make sodium/potassium stearate - which is soap.  The impurities are the problem!

  • TopbirdTopbird Posts: 8,247

    I also add mine to the compost bin but only in very thin layers because it can form a thick alkaline pan or sticky layer of compacted ash which doesn't rot down. (Been there - done that.. image

    Best kept in a covered bucket next to the bin and sprinkle in a couple of shovel fulls each time you add material to the compost bin.

    Heaven is ... sitting in the garden with a G&T and a cat while watching the sun go down
  • Wow that's some great replies thanks all, will use a magnet to get any nails out first though

  • From what I remember of what was said in reply to such a question on Gardner's Question Time:  Wood ash is also fairly high in lime, so use on your brassicas etc.

    Bob Flowerdew recommends storing the ash somewhere dry for up to a year or three when, apparently, it will mature into something wonderful to use on the whole garden.

    As for soap making - apparently soap made from wood ash is soft and slimy, it doesn't form into bars like soap made with sodium hydroxide does.

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