It seemed that as soon as I mentioned the mild winter weather being good for watching the activities of worms, half the country turned white with frost, sending the worms deeper into the soil. Thankfully, it’s warmed up and the worms are active again. After reading some more about earthworm middens, I’ve been out looking for them. Not hard, as I spend much of my day outside, so there isn’t far to go. Sure enough, once you actually start looking, you can see that there are a great many leaves standing upright and half way into the soil, all pulled in by worms. This led me down to the end of the courtyard at home, where there is still a layer of fallen leaves that haven’t been cleared away. I got a rake out and started raking gently to see what was under the leaves. Sure enough, while most the leaves were easy to rake up, small mounds were left that didn’t want to shift.
These mounds of old leaves were 6-10cm across, pretty much circular and fairly evenly spaced. Pulling at the bits of leaf, I found resistance, as they were partly embedded in the soil under the layer of gravel. Was it a worm midden?
I carefully pulled away the top layer to see what was underneath. When the ‘cap’ came away, you could see the worm’s tunnel in the middle of it and see where the entrance was blocked up with partially composted leaves.
Without the cap, the worm’s tunnel into the ground was quite clear - there was even a small worm at the tunnel entrance, but I don’t think this one was the main user as it didn’t look big enough. Had this one simply been in the leaf layer at the surface? With more questions starting to form about just what is going on down there, I put the cap of the worm midden back in place. The next thing to do is to leave these leaf mounds as they are and see how long it takes for them to disappear.
It is quite a surprise to find all this worm activity in the courtyard, because I know what’s under that layer of gravel, having attempted to dig a hole in it and giving it up as a bad job. The gravel is about 4cm deep and beneath that is deep, thick, hard clay, the kind of stuff you could make bricks out of. If worms can navigate through that stuff, they’re tougher than I thought they were.