William Bronson

Here's a nice first hand account on using this plant,complete with nice photographs:
https://foragerchef.com/silphium-cup-plant/

I totally understand using nice new materials for other people's raised beds!
I use cedar dogeared pickets measuring 6'x5.5"x 0.5" , as the boards for these projects.
It's hard to join two 1/2" boards neatly and securely without involving  a 2x2 or 2x4 .
I haven't found any cheap, durable non-toxic 2x materials.
I have ripped cedar boards in thirds and then sistered the results together, but I suck at carpentry and safely ripping  narrow strips of wood is difficult for me.
Going forward I will be trying steel framing brackets for joining these thin boards at corners and mending plates for joining them end to end.

If you are willing to use cardboard, that is the easy route.
The forever chemicals found in cardboard would probably stop me from going that route.
Hardboard is a wood based sheet good that is created without glues.
It's the same material pegboard is made of.
I have used in direct contact with soil, where it lasts for years of use.
As a liner for a bed, it should last a long time.

The pressures involved in making hydrochar are much higher, 290 psi on the low end, than pressure cookers , generally 15 psi on the high end.
Water heaters are rated for 60psi, but steel pipe has very high pressure ratings(200-650), but low internal volume.

If hydrochar can be made at lower pressures while taking more time, that would be a useful tradeoff.

I generally don't line my pallet wood beds at all.
My soil settles in and doesn't spill out from the openings enough to worry about.

That said, I have built a few lined with surplus tile and I plan on doing this more in the future.
I've settled on using metal roofing washers and short drywall screws as the best way to affix them to the wood.
The tile I use is ~12"x 24", so it fits the dimensions of a pallet rather well.


For you I would suggest aluminum gutter guard.
It come in rolls 6" wide, and it shows up in surplus shops all the time.
It will go on easily with a staple gun.
If the holes in that are too small for your needs, 6" rolls of aluminum flashing might serve.
I would use sheet metal screws to affix that.

If you want to use burlap and make it last, a coat of cement to create "petrified hessian" /burlap concrete might do the trick, but a soak in a boran solution might work just as well.

Very interesting.
It seems like a great use for renewable energy, both as a way to store carbon and as a way to leverage abundant daytime solar to provide for night time  power usage.
Not a lot of details on what actually goes on inside one of the pressure vessels, or what is produced aside from the hydrochar.
Biochar production separates a variety of gasses from the char.
Usually the flammable ones are burned and the others simply released .
Some times people collect and condense the gasses into water,yard and wood vinegar

Does process of creating hydrochar produce similar leftovers?
Are they used to fuel the process?
I think the hydrochar might retain more hydrocarbons than biochar.

Looks like hobbyist are already making hydrochar at home:

My experience as someone who is neural atypical with a late in life diagnosis is mixed.
It helps my morale to know that my struggle to do normal things isn't just a character flaw.
On the other hand I have witnessed a diagnosis being used as another reason to not do things at all.

Kevin Feinstein II wrote:How did people deal with this 200 years ago, or even more recently?  No plastic tarps, no cardboard.

Manual cultivation.
It tends to be a lot of work, but people did not have as many choices about how to make a living as they do now.
There were also animal helpers like the cotton patch goose:
https://en.wikipedia.org/wiki/Cotton_Patch_goose

Is the fiberglass you references supplanting mixed in for crack resistance or separate as a layer for of insulation?

I wonder if guar gum, psyllium husk, or ground flax/chia seeds could substitute for  xanthan.

Sounds like the difference is how much air there is in the mix.
He does say the drill mixed recipe did not totally fill the form, but suggested adding more air.

The block that came from the concrete mixer weighed  22 lbs.
Working from that, and 20 dollars a bag, I get almost the same cost for cement that you did.
Like any kind of concrete, the ratio of aggregate to cement is key to the cost of a building unit.

I would like to know how long the soap and xanthan mixture remains stable.

You make great point about filling the blocks not helping insulation values because or thermal bridging.
If anything ,aircrete bricks filled with concrete makes more sense.
Using aircrete as an infill for stud or post and beam structures makes sense to me.
Using it as an insulating parge might work, but I'm not sure how it would affect where condensation might form.