We happened into a brilliant gardening hack this year, when almost all of our sheep’s fleeces were damaged by canary stains. So far our experience using wool as a ‘weed block’ and mulch has me totally sold on the effectiveness of wool and it’s place as a gardening necessity.

In the past, we have sort of mulched straw, but with mixed results because we never seem to get enough put down, and it would always break down so quickly that the weeds just thrived and grew up over it. I completely get that if applied in large enough amounts and at frequent enough intervals, it is a very effective garden aid, but I am absolutely the worst at getting around to it.

One of the great things about the wool, is that it definitely lasts for an entire summer, and I suspect that ours will still be around next year. While it does not kill and keep down weeds the way that plastic does, it severely retards the weeds’ progress and makes the occasional hand weeding all that is necessary. This is especially true if you prepare your garden bed using plastic in the off season before laying down the wool.

I have also noticed that the plants mulched with wool are much less stressed during the heat of the day than those without, and are growing bigger than anything I have ever grown in the past. (Okay, that’s not saying that much, I am a TERRIBLE gardener, but this year you could mistake me for mediocre!) The soil under the wool is usually always damp and stays close to 10 degrees below the ambient air temperature according to our readings, and I assume slightly above nighttime temperatures, though I haven’t actually measured that.

Woolen mulch

I recently read an article about how pelletized belly wool makes a great soil amendment, due to its nitrogen content and more uniquely the biological habitat it creates for microscopic soil organisms. While the mulching process certainly functions in this way to a more limited extent, due to the fact that it is resting on the surface of the soil the interactions with soil organisms are slowed way down. The the breakdown of the wool into its biologically available nitrogenous components is also slowed way down, so I recommend laying a green mulch (chopped up weeds, legumes, straw and/or cool manure) under the wool layer for best results. The organic matter that collects on top of the wool should be scooped up and stuffed underneath as well to prevent it from breaking down your mulch more quickly.


Sourcing wool is definitely the limiting factor in this system. While much of the lamb raising industry treats wool like a waste product in the US, most producers do try to charge at least something for their wool. Depending on if you can find low quality wool in your location, you may be able to source this amendment for free, but I personally feel that it would be worth the cost to pick some up, especially for those with small intensively managed gardens. Why not reach out to your local lamb producer and see if they have any surplus wool you could have, buy, or trade for?

Thank you for taking the time to read about our farm; please share what cool things you have been experimenting with in your own gardens!


P.S. Canary Stains, for those who are curious, are caused by a bacteria that feeds on the sweat and oils produced by the sheep. They make the lower parts of the wool appear bright yellow, and unfortunately they weaken the integrity of the wool for spinning. This staining occurs when the sheep has it’s fleece during warm weather, which we have done the last two seasons. As fine wooled sheep, our polypays seem to get run down if they have their full fleeces in our continuously wet Oregon winters, so we have been shearing in the fall. Unfortunately it appears we may have to shear twice a year to prevent these stains; but, such is life! 🙂

One thought on “Woolen Mulchin’”

  1. Wool is also an excellent water retainer and acts like perlite holding moisture that is available for plants when needed. Mixed with other compostables or compost itself at a ratio of 10% wool it is an efficient fertilizer as well. Made into pellets it becomes marketable and also available for large scale farm use on problem soils.

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