I'm finishing up my first Hugel and plan on immediately sowing some cover crop. My question is should I/can I put mulch on top of that? Will the cover crop be able to come through? I have access to free wood chips and I am concerned that they might not be able to make it through. I guess this doesn't apply to just Hugel mounds but it is my current scenario. I've really only ever used mulch on established plants.
Since you said "cover crop" I assume you are seeding directly into the hugel mound. Seedlings need nitrogen to get them going, even nitrogen fixers, even the microbes in the soil. Wood chips are high carbon and their presence will "suck up" all your nitrogen. So, my assumption is that you won't get much growth unless you counter with a strong nitrogen source and that might be hard to balance. In other words, I wouldn't.
Personally I would be reluctant to put wood chips on a Hügel, even when not sowing anything immediately there. Fresh Hügels always take some time to settle, causing cracks, small collapses and such. So you might want to even the surface every now and then for your plants to grow better, but wood chips would make this difficult, or they would get mixed up with the soil.
Can you spread the wood chips around the Hügel? I'm always gathering lots of wood chips and put them on the paths between the Hügelbeets.
From what I've heard from a number of places, wood chips won't rob nitrogen if put on the surface. There's more debate about if they're mixed into the soil.
On the one hugel I did, the only things that grew through a couple inches of grass mulch were sunflowers. That was in mid-summer in Montana = dry. If you can reach everywhere on the hugel that you want to plant, how about spread wood chips and then spread a spot, plant 4 seeds and lightly cover that spot back up. Wouldn't be time effective for a lot of coverage but for bigger plants on a smaller hugel it could do the trick...
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