Every spring when I jet wash my driveway I collect about 80 litres of moss. I have a large garden with many plants that can benefit from any nutrients I throw on them, and I’m thinking whether the process of jet washing has effectively killed the moss and it can be safely used as a compost? Or does it need to remain in the compost bin for a year before I can use it without harming the plants?

Is this collected moss effectively peat? And given the jetwash process involves no chemicals but the typical hard water of London would this compost be acidic or alkaline?

  • Does the jet wash use hot water? Does it use any chemicals?
    – Boba Fit
    Commented May 3, 2023 at 16:26
  • @bobaFit no hot water, just standard tap water, and already mentioned no chemicals
    – Meitham
    Commented May 4, 2023 at 7:52

2 Answers 2


It's not soil, and it's not effectively peat, (first, it's almost certainly the wrong species, second, it's not long dead and sitting in bog water, which is a succinct description of what the harvested peat moss has been doing for a few hundred years) and there's no particular reason to think it's dead, it's just been relocated from where it was growing.

You can compost it.

If you have a place it would be useful growing, as a living mulch or soft path covering, you can probably spread it and have it grow, if conditions are suitable.

  • > "here's no particular reason to think it's dead". Wouldn't the strong pressure of the jetwash damage and kill the moss
    – Meitham
    Commented May 4, 2023 at 7:59
  • 2
    Have you met moss? It's tough stuff. It comes back every year where you wash it away...
    – Ecnerwal
    Commented May 4, 2023 at 11:47
  • 2
    ...and the blender method mentioned in another answer doesn't kill it, being a commonly used propagation technique.
    – Ecnerwal
    Commented May 4, 2023 at 12:12

I was just thinking about this a couple of days ago as I scooped up moss near my garden and replaced it with hemlock mulch. The moss is still alive, it's very hardy. Plus, it's home to untold thousands of tardigrades, which are pretty cool little guys. I put mine in the compost heap for next year, but I bet wherever I put that compost, moss will sprout. It's really a remarkable plant.

Here's a cool idea: Get a decorative wood-wool tile from a company like Kirei, put some moss and a little buttermilk in an old blender you don't use for food, blend it up and spread it on the tile. Keep it moist by spraying it with water every couple of days. Soon moss will have covered the tile, and you can hang it on your wall as a tiny vertical garden. Don't forget to keep it moist. Hang a strong magnifying loup near it for hunting tardigrades. Great gift for a kid interested in science.

  • 2
    my vote for best first answer!
    – kevinskio
    Commented May 3, 2023 at 13:20
  • Wow, yes! Great points! :) Commented May 4, 2023 at 17:57

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