Lots of people make small batches of biochar in kilns, retorts, rings and pits. To move the char, most people shovel it out. When your batches of char get bigger, unloading is a lot of time and energy. How to improve that? There are two main challenges: moving the char out of the kiln, and getting it to the desired size. One option for moving the char is to use a kiln vessel, off the ground, that can be tipped to pour its contents out. This isn’t an option for those of us using pits or rings, or much larger metal vessels. For these, the main options are shoveling the char out, or sucking it up ..read more

I’ve spent a couple weeks researching, and this is what I’ve learned about milling your own wood with a chainsaw, and in particular a battery-powered chainsaw. Note that I have not actually done any milling yet, but after so much reading, searching, shopping and youtube-ing, I feel like I’ve learned enough to share and be useful. First of all, some people will dismiss it completely, saying that chainsaw milling is too tedious, too slow, too limited. They point out a proper bandsaw mill is more efficient, faster, better, etc. No doubt they are right, but many of us already own a chainsaw and wa ..read more

After a few weeks of research, I think I know what new chainsaw to buy. The DeWALT DCCS677 with DCB615 battery For context, battery chainsaws have not been considered “serious” in the past compared to gasoline models, but now (as of Summer 2022) there are abundant powerful options, for up to a 20″ bar. For nearly 4 years, I’ve been happily using a 14″ Makita XCU03 (LXTx2), and I’ve been delighted with the quality and reliability, but now I need something bigger and more powerful. Here’s what I found about the power of chainsaws now available: Bar Volts Max Power (kW) HP (kW*1.34) Chain spe ..read more

I did the harvest today, and here are the results, in terms of grams of potato per plant: Yukon Gold 144 Dark Red Norland 113 Kennebec 283 Red Gold 244 Kattahdin 75 La Ratte 13 Papa Cacho 27 This is pretty awful.  For comparison, just planting random store-bought yellow potatoes gives around 250 g/plant, while better-performing varieties (Island Sunshine and Yukon Gem) on my farm have produced 400-800 g on average or even well over 1 kg in lucky cases. The one promising bit here is the Kennebec: Kennebec did the best in this trial, basically due to surviving a few ..read more

Here’s the chronology on the potato trial: 2020.07.20: planting day 2020.08.16 (day 16): all the potatoes have emerged and are growing nicely, except for the smallest varieties (Laratte and Papa Cacho), which are barely emerged and tiny plants. 2020.09.03 (day 38): The plants have been mounded (hilled) with regular garden soil.  Nearly all plants are showing early signs of some kind of blight, starting with brown spots on the leaves: One of the yukon golds is already completely blighted, down to bare stems:2020.09.12 (day 47): Almost all the plants are completely blighted to the poin ..read more

Concerning volume.  In my previous biochar post, I summarized that my two rectangular lined pits were producing around 1.3 cubic yards of char per firing.  Since then, I’ve been told that a simple earthen pit could produce as many as 5 yd3 in a single firing!  Let’s calculate how large that would be. A round pit with a flat bottom is basically a truncated cone, which is like this but upside down: 5 cubic yards is 135 cubic feet. To be able to step down into the pit, I don’t imagine it being much deeper than 3′ deep (my current pits are around 2′ deep, and it’s quite a ..read more

Today I examined the seed potato that we got for the trial. 7 varieties. Many were starting to decay.  No doubt proper potato storage would involve a temperature or humidity controlled environment, but we don’t have such a thing, so a few were lost.  Nearly all were at an advanced staged of growing eyes, many also had roots. I planted them in one of our typical well-drained raised garden beds, 3 x 21 feet, with enough room for 38 plants.  All our beds are similar in regards to soil makeup: the base is Hamakua clay soil, highly improved with organic matter over the years (m ..read more

We’ve always grown potatoes occasionally, since I was growing up here, but recently I became more interested in really knowing potatoes and hopefully increasing production.  To this end, I started a spreadsheet to track planting and harvests, and ordered some seed potatoes for variety trials. Background: We used to just use organic potatoes from the health food store. Some would start to sprout before we got around to eating them, and they got planted in the garden. The yield was never very good, but at least it made a few small potatoes per plant, so it was worthwhile.  We had ..read more

It’s been seven years since I posted anything to this blog, but it’s a reasonable place to put things I’ll want to refer back to, so… There are currently two biochar pits. Pit 1 is the original, and Pit 2 (built July 2015) is a larger pit which incorporates lessons learned from the first pit. I always fire both together.  When the pit is fired then opened up later, there is a gap at the top with air and a few chunks of wood that were not fully charred, which are removed, leaving a depth of char which is less than the depth of the pit.  Here are both pits, freshly opened, with th ..read more

Tons of work got done during the 3 weeks there, including: Took down and partly processed 6 very large cypress trees above the tea field Started new long-term compost pile Planted several dozen new tea plants, mostly Y/Y cultivars Lots of wood moving and splitting Re-built the char pit with real firebrick, which should last forever Several burns of the char pit. Lots of thinking about how to make the process easier, mostly in the sifting-crushing-sorting.  Right now i am thinking about building a low-tech Rotary Sifter, something like this. Combined with some kind of crushing phase ..read more