Like Anna, I think I have a mulch obsession. I can’t get enough of the stuff!
Last week we had a truckload of mulch delivered from the Dunmore waste depot. It cost about $115 to have them deliver 9 cubic metres (12 cubic yards, or 4.6 tons), which I think is money well spent. Apparently you can go and fill your trailer with the stuff for free, but look at my trailer compared to the pile. I think it would have taken at least 10-15 trips to drag home that much mulch, and I would have had to do all the shovelling myself!
Can you see the steam rising out of the top of the pile? It’s partially composted, but still pretty hot.
And here’s a close-up to give you an idea of the structure and composition of the mulch. It’s made up of all the municipal green waste, shredded and partially composted. There’s a good mix of fine compost and larger chunks in it. There’s also more plastic and bits of painted wood than I’d like, but not enough to be a big concern. I can pick most of it out as I use the mulch.
So what am I going to do with all this mulch?
I’ve been digging some new garden beds, and in between them I’ve dug deep paths on contour. The paths are about a foot deep, and I dug that soil onto the beds to make them a little higher. In the bottom of the trenches I’m laying down cardboard (to smother any kikuyu grass that tries to grow back), and then filling them with this mulch.
Because the paths are on contour, they hold water when it rains and act like swales. The mulch soaks up the water and forms a reservoir, but because it’s loose and chunky the surface is still fine to walk on. The water will then be released to the surrounding garden beds slowly over the following week or two, reducing the need to water. As the plants in the beds get bigger, their roots will seek out the moisture in the paths and hopefully grow nice and deep and strong.
Normally you’d shy away from putting so much woody matter on garden beds for fear of locking up nitrogen in the soil. But the paths are between the beds, so the soil in the beds will not be affected. In addition, mycelium (fungi) will colonise the mulch paths. Plant roots and soil microorganisms work together with the mycelium to feed each other, for the benefit of the growing plants.
When the mulch in the paths eventually breaks down, it can be dug onto the garden beds as a rich humus dressing, and new mulch can be laid in the paths again.
Rob over at One Straw has a great explanation of the concept, which he calls pit and mound gardening.
It’s kind of like a mini swale/hugelkultur – garden paths don’t have to be unproductive!
I’ll post some photos soon. Hopefully I’ll get to do some more work on the garden beds over the weekend.