Harvesting leaf duff (leaf mould) from the woods is a great way to increase the organic matter and mineral content of your gardens while adding beneficial microorganisms and fungi.
Steven Edholm recently posted on the benefits of using leaf mould over at the Skillcult blog:
So, why leaf duff? I use leaf duff mostly on seed beds. Leaf duff is not just shredded leaves or any organic matter. One trait it has is that small flat pieces are efficient at surface coverage. Why cover the surface? To keep water in and protect the soil. Almost any mulch can protect the soil for losing water. It also protects the soil for the hammering effect of rain and watering, which can pulverize it and destroy it’s structure. Most agriculture systems use cultivation for a reason, it breaks up soil crusting. compacted soil wicks away moisture faster by capillary action. Loose soil can act like a mulch, greatly slowing water loss. Crusting also inhibits the penetration of water into the soil, so we not only have rapid loss, but less infiltration.
Lets say I plant a bed of carrots. The seeds are very small and they take a long time to come up. If I don’t cover them at all, as soon as I water, the soil begins crusting over. Each time I water, it will become worse. Once crusted the water I do add will not penetrate the tight soil surface as easily and what does sift through will leave faster. Adding almost anything from coffee grounds to saw dust, to compost will help alleviate this problem. Leaf duff, sifted through a half inch screen, if applied carefully and sparingly, efficiently protects the soil, but will still allow the seeds to come though. If I don’t cover the bed with anything, my carrots are going to be hard to keep moist enough for good germination. Since the take a long time to come up, and are planted shallowly, I can’t intervene by breaking up that crust. I plant carrots on an either 2 inch or 3 inch grid pattern, so even when they do come up, cultivation is very difficult. I usually mulch lightly to get them up, and when they have all emerged and grown a little, I sift more fine mulch over the bed.
We’ve had this exact problem with carrots. My solution has been to use finely sifted compost to cover the planted carrot seeds; however, getting some free mulch/compost from the woods is a great idea.
Steven also has a super simple passive method of accumulating larger quantities of leaf mould:
“The system is simple. Going out and collected a lot of this stuff over the years, you notice that it is deeper where divets are created in the landscape. Leaves move downhill quite a bit and accumulate in low spots or behind dams that create hollows. So I set up some logs in strategic places accross the landscape when out doing forestry work. I think the steeper the hillside, the more, or faster, leaves will collect. It takes a few years to gather enough and break down adequately, but it’s a simple intervention and you can revisit them over and over once set up.”
I’ll try this method on my carrots this year and see how it works.