Last year, I had to have a dying hickory in my yard cut down. While I paid to have most of the trunk hauled off, I still have a pile of the limb wood. I had decided a while back that I would plug these logs with shiitake spawn and make shiitake logs. Its best to do the plugging after the last hard frost, so I waited until yesterday to do the work.

I ordered my plug spawn from Fungi Perfecti, a neat company near Olympia, WA. They’ve got spawn for lots of different strains of mushrooms, but I love shiitakes and shiitakes love hardwoods. The spawn arrive in a little bag like the picture on the right. The spawn themselves are small dowels, about 1.5″ long, with a spiral groove cut into the side. You can clearly see the white mycelia from the shiitake in the groove. There is also some grain in the bag as well, which I surmise are how the dowels were inoculated.

I had ordered my spawn about a month ago, so by the time I pulled the bag out, there was plenty of mycelial growth in the bag, which you can see in the picture on the left as the white matting around the dowels. According to the instructions, this is normal and probably wouldn’t have been so bad if I’d used the spawn more quickly. Fortunately, no mushrooms had begun to bud, so I didn’t have to pull those off.

When I pulled all my stuff out to start the project, I hadn’t read the instructions carefully enough. I needed a 5/16″ drill bit to make the holes in the logs for the dowels. Unfortunately, my little B&D cordless drill’s largest bit was 1/4″. I already had a rubber mallet to tap the dowels into the log and I’d stopped by a fabric store a few weekends back and gotten some untreated burlap to cover the logs with to help them retain moisture. All I needed at this point was that drill bit. A quick stop by Northern Tool solved that problem, and I could get down to log selection.

It’s best to get longer, larger logs. I didn’t have anything shorter than 14″, since the arborist’s crew cut the branch wood to firewood length. I don’t think that’s a huge problem, though. What was more important is that the wood not already be inoculated with competitor fungi. This means that I selected from logs that had not been touching the ground and that didn’t show any splotchiness at the end. None of the logs showed any major saprophytic growth – no turkey tails or other polypore mushrooms like you’d expect on rotting logs. Most of them had the lichen-like surface growth in some places – this was on the tree when it was still erect. I brushed most of it off and hoped that the shiitakes would out-compete anything left.

I also didn’t know how many logs I could plug. I had 100 dowels – the smallest order I could make. I figured that would make about 5 logs, since the holes needed to be spaced fairly closely at about 4″. I drilled a few test holes into the first log and tapped the dowels in, pretty much like I the picture to the right. The mallet collapsed the mycelial growth at the end of the dowel, but slid into the hole without a problem. The spiral grooves will hopefully have protected the mycelia inside them from collapse. Elder Daughter, who had come outside to help me, was able to tap in most of the dowels, even with her cast on, which she enjoyed doing.

At this point, I could have covered the holes with a dab of hot, food-grade wax. I didn’t do that, which means that I’ll probably need to keep a more careful eye on my logs to keep them wet and to keep ants from trying to eat the mycelia. If the ants start bothering the logs – well, I have some diatomaceous earth with their names on it.

I wound up stuffing some of the extra mycelial mass from the bag into the holes in front of some of the dowels. I drilled slightly deeper holes into the log to accommodate the extra “stuff.” I don’t know if that will help speed along the inoculation or not, but I figured it might and it wouldn’t hurt. The picture on the left shows the first two logs completely pegged. Each log took between 16 and 20 plugs, which means I had enough to plug 6 logs – though the last log only got 9 plugs, which hopefully will be enough to get good colonization of the wood.

At this point, I needed to get the logs good and wet and cover them up. I set them under the garden sprinkler for a little bit, then wrapped them in the burlap. I moved the whole package to the shady side of my garden shed, and used a watering can to put about four more gallons of water over the whole thing. This soaked the burlap through so it wouldn’t wick water away from the logs. The instructions recommend that the whole thing be watered once a week, depending on how arid the climate is, and whether you used wax on the holes. I’ll check it a little more frequently, since I know I’ve got a very healthy ant colony nearby.

If all goes well, the logs will be fully colonized in somewhere between 6 and 12 months. At that point, I can encourage a fruiting by applying a lot of water and a little sunlight. This went well enough and I have enough logs left that I’m considering ordering more plugs, even though I have no idea what I’ll do if I get that many shiitakes! I have a couple of friends to whom I may give ready-to-fruit logs, assuming all goes well. And well, I do love shiitakes, so not having to pay out the nose for them will rock. The only question is whether I’ll get mushrooms this year or next.