Phil Stevens

Ben, your points on asbestos contamination are totally in line with my thinking. It's amazing the level of unproductive economic activity that has been created by people freaking out over the stuff. But in a situation with sandy soil that's easily disturbed and windy (like next to a beach) I'd still feel better if there was a layer of topsoil and plants keeping it from being liberated.

Something else I wonder about, if a test result came back with measurable amounts: Once you know there's a problem, you are legally obligated in many places to disclose it to the likes of future buyers, local authorities, and insurance companies. I would look for a test that did not include that particular substance in this case.

Hi Kathryn, and welcome to permies! I admire your willingness to be a steward of a piece of land with a history of abuse, and think that it was lucky to find you.

If you're able to get a soil test done, by all means do so. The things you are probably most concerned are heavy metals like lead, mercury, cadmium and arsenic. Next you might want to know about persistent organic contaminants like used motor oil, diesel, solvents, paints, etc. Then there are the nasties like asbestos, which could be an issue if the place was used as a dump for old building materals.

As far as remediation goes, there are a few things you can try. Mycoremediation with fungus can clean up organics. Bioaccumulators such as sunflowers will take up heavy metals, but then you need to cut them down and take them "away" once they have stored the toxins they took out of the soil. You can also build raised beds with barriers to prevent plants rooting in the contaminated soil if you really want to grow things but are uncomfortable with what they might absorb.

I'd probably go with a staged approach, depending on what the tests came back with. Raised beds and containers to allow you to start growing, and rotations of wood chips with mushroom slurry followed by crops of sunflowers to be carted off to some place that is set up for that sort of thing. After a rotation, get another round of tests on the soil to see what effects you've made and if you're happy with the results, start planting in it and move your remediation efforts to another part of the section

Fear not, Ryder. The smoke and balkiness is exactly what we expect when firing a new RMH with cold, wet mass. As things dry out and warm up it should roar to life and behave like a proper dragon. Keep burning fires, using small and well-seasoned wood, and you should see the trend with every burn.

Mike, that PSU rated for the full load would be right at the ragged edge of its capacity and would probably die an early death. The advice from John is worthwhile...get something with some headroom.

This is a job for Ohm's Law.

P=VI (Power = Voltage * Current)

We know the power is 90W and that it operates at 12V, so we solve for I to see how much current it draws:

I=P/V = 90/12 = 7.5 amps

Now we should figure out what sort of resistance that heater presents as a load to the curcuit:

R=V/I (Resistance = Voltage / Current)

R = 12/7.5 = 1.6 ohms . . . this is almost a short circuit

A typical laptop power supply provides 18-22V at around 3-5A. It wants to see a load in the range of 4-6 ohms. Less resistance will mean that the load is asking for more current than the PSU can really deliver, and in trying it will heat up and probably die. The preferred failure would involve a fuse blowing in the unit, but there could be a light show and even sparky-burny type shenanigans.

Look for a power supply that is rated for the load you're attaching, ideally with built-in safety measures (and a UL logo on the outside). A decent sized 12V battery charger might work.

Hi Rebecca, the good news is that the snow may be protecting your fig from the coldest temps. Not much else you can do for it right now, but when the snow is gone check for damage and prune back any broken branches. Cross fingers and wait for new growth in the spring, and prune out any wood that doesn't show signs of life.

We almost never get snow here, but had three days of it nearly ten years ago (in late winter just like you guys) and our fig tree didn't mind a bit. But it didn't get nearly as cold as what you're dealing with in Texas, so this isn't much of a data point.

Oooh, pretty. That's a good teaching tool as well.

I did this the old-fashioned way: I made a reverse mold from wood and then poured castable refractory. I did top and bottom halves instead of L-R so that joining them wouldn't be critical. The RMH is a 4" system in my glasshouse and it performs well, but I will need to demolish and rebuild the core sometime soon (hopefully before cold weather returns) because it has cracked and spalled pretty badly with use. I have gotten three seasons out of it and lots of education, so it's been a good first step.

Here is what I learned:

* I really should have set up a vibrating table for the casting process. I suspect a large part of the deterioration of the refractory material is down to the voids and inconsistencies in the cast body.

* The next iteration, if it's a J-tube, will have some extra depth to allow ash buildup without throttling airflow. Several times I've gotten reverse draft because too much fuel lodged as coals in the burn tunnel.

* Those intricate castings are weak at corners and transitions. If I do another cast core, I will make slab forms instead of the hollow molded halves. Sort of like firebrick splits, but with the detail of Peter's design fully incorporated. Fit of the pieces will be done with simple rabbets or grooves to allow for differential expansion and contraction, as I think this has been the number one driver of cracks in my core. I want the parts to shift within limits and not stress the weak spots.

Or, I might go for the gusto and build a batch box. Traipsing out to the glasshouse every 30 minutes on cold winter nights does get old.

Hi Lori. Plain charcoal will help, but biochar really is better because it's produced at higher temperatures which yield a higher porosity.

A 10% by volume mixture is more or less what I would aim for. 1.5 cu ft would be about right, and there would be no harm in adding extra. You could add it in portions on a daily basis for a few days, mixing it a little deeper each time. Note Trace's advice about it being ever so slightly damp...you and the birds don't want to breathe the dust. But don't start off with saturated material, because the absorption of high-nitrogen moisture is how the ammonia inhibition works.

After the biochar and litter has done its dash, compost it and use in the garden.

My current technique (always evolving) is to mix biochar and compost about 50/50 and spread it on top of a bed. Then I get out the broadfork. As I open up the soil, the compost-biochar blend falls into the cracks and the whole bed fluffs up. I then plant into this and mulch with copious amounts of wood chips or shavings. This is working pretty well on established beds.

When creating new beds, I usually put down some cardboard or paper, then layer lots of grass and weeds on top, and cover with a mix of soil, compost and biochar. Mulch goes on last.

Hi Lori - I use biochar in my chicken coop and a friend of mine uses it in her quail pen. It stops ammonia formation almost instantly in a deep litter system. If you can get your hands on biochar, or just some good quality charcoal, give that a go and see what you think. I'd recommend a wood chip mulch with about 5-10% biochar by volume, stirred around every few days to keep it aerated.