Compost powered Root zone heating references

We’re just about to implement some compost-powered root-zone heat systems for a small, indoor plant nursery and the new high tunnel.  These are the best references I came up with on researching the implementation of  compost powered root-zone heating systems for greenhouses or other closed growing environments.

Hope you find them helpful!


Cornell Small Farm’s energy research compost pile.

All of this was inspired by Jean Pain:

A french site with the most complete info I’ve found on Jean Pain so far, with some good links to videos with subtitles at the bottom of the page:

The New Alchemy Institute’s paper of a very well referenced compost powered greenhouse:

Here’s a local copy of the same PDF linked above just in case that site isn’t available in the future:
new alchemy (local copy) pdf

I really love this super low tech, simple, and practical method of achieving root zone heating:

And if you’re wondering how many BTU/hr/ton of compost you can get (1000) Cornell Small Farms did some research:

Root zone heating can provide massive energy savings:

And some practical advice for the installation of such systems:




Biochar, The Slow Burn

We’ve started producing biochar at the farm, primarily for our own use, but if you twist my arm hard enough I’ll sell some as well.  You can see our ‘how to’ video produced in October 2020 here:

I wanted an easy place to refer back to when I forget the recommended ratio to mix with compost for a good biological/mineral/nutrient pre-charge and subsequent application rates.  So here it is!

Biochar Application rates:

  • Remember that raw biochar will absorb minerals and nutrients in your soil for the first couple of years, nature will correct, so not a big deal but if you want to give your soil and immediate boost, pre-charge your biochar before application
  • Easiest way to get it ready for direct application is to mix in when building compost piles
  • Mix up to 1:1 or 50% by volume with finished compost and let rest for a couple of weeks before application
  • Or up to 1:3 or 33% biochar by volume in unfinished compost for good mineral/nutrient/biological pre-charge of the char before application (higher biochar ratios may shut down your pile)
  • Apply pre-charged biochar directly to root zone or in seed furrows at a rate of 1% to 10% biochar by volume of amendments applied.
  • If applying bulk, pure biochar directly, go for 1000 to 2000 lbs biochar/acre (raw or pre-charged)

The key to a highly productive, low tech/low cost biochar pit burn:

  • Start your fire in the bottom of the empty pit
  • slowly add material until the fire just starts to smoke
  • let the fire build back up and compact the pile/add more material before any white ash is apparent on any surface
  • frequently compacting the burn pile with a heavy poker, crushing coals off and tightening raw wood, really helps final yield
  • take care to fill in gaps which might burn too quickly
  • if you don’t watch your fire, your char will burn up
  • THOROUGHLY quench the fire with water, removing any unburned wood where live coals might be smoldering, and stir the coals until no more steam or smoke is produced
  • Let the char cool/drain overnight and dig out into your compost piles.
Low tech, low cost biochar pits can produce good char even from less than ideal wood sources if tended properly.

For our biochar pit (6′ diameter, 4′ deep) it takes about 8 hours to char 6 cubic yards of bulky less than ideal wood.  A well tended burn will yield around 250 gallons of char.

Another great, simple way to make char at lower quantities is to use a 50 gallon barrel with no holes and an open top set at a 45 to 60 degree angle. Just build a small fire in the bottom and slowly feed it until it smokes then wait until it starts to ash. Repeat until full, tip it upright and quench with water. Here’s a video of that method:

Best references I’ve come across to develop this process:

Various other biochar links:

And if you want to go deep into the science:

Though we haven’t done it yet, I’ve recently (February 2022) learned from Dr. Olivier Husson’s interview on the regenerative agriculture podcast ( that paramagnetic biochar can be produced by soaking your source material in a saturated iron sulfate solution for 24 hours before pyrolysis. I’m looking forward to trying this technique at our farm. Note: this can produce a very acidic biochar (pH around 2.5 at 400 °C, around 6 at 700°C…from direct corespondence with Dr. Husson), so how you inoculate your biochar after production may need to be adjusted accordingly.

How can I help “Save the Bees?”

I get asked this question a lot, and perhaps somewhat surprisingly, the answer isn’t ‘ become a bee keeper’ (there’s a lot of evidence that feral bees are doing just ok, often better than kept honey bees), and our transport of bees/honey/pollen around the world in the age of globalization has done a great job of transporting parasites, viruses, and other maladies, which have now started crossing to other species.


So you want to ‘save the bees’, then start thinking about all insects, and our use of toxins in the food system.  Here’s recent reply to a visitor of our website which sums things up as succinctly as I can:

———- Forwarded message ———
From: Peter Brezny <>
Date: Thu, Oct 11, 2018 at 4:17 PM
Subject: Re: Interest in becoming a Bee Guardian
To: <redacted for privacy>



Thanks for the note and your interest in protecting pollinators on our planet.
Sounds like you’re heavy into food systems and education.  Well done!
As I hope became clear from your reading on our website, honey bees are the economic indicator we follow that helps us understand just how much peril all insects are in at the present time.  Only 2% of insects on the planet are harmful to crops, and many of the other 98% are ‘pest’ insect predators!.   All of them are in drastic decline and pesticides (duh)/climate change are the problem.
The very best thing you can do to protect pollinators is not to become a beekeeper, but to work to create pollinator habitat, and advocate for pesticide free zones and organic farming/chemical free farming techniques.  Everyone with a yard has the chance to create a safe habitat for pollinators.
There are a lot of excellent resources directly related to this:
Keep up the great work!
Best Wishes,

Peter Brezny
Psycho Chicken Eco Farm

NCSBA Journeyman Certified Beekeeper

Spring Honey Bee Grafting

WNC experienced pretty significant honey bee colony losses over the past winter.  The Buncombe County club reports an average of 70% loss.  Our bees were wiped out as well, so this year, I’ve teamed up with friends Joseph and Erik, to raise queens from local, treatment free survivor stock.

For a better understanding of why local, treatment free, bees with good genetics is so important, check out:


Bees are expensive to buy, so this year (in addition to buying some bees, as locally sourced as possible) I’ve put up bait hives in multiple places with the hopes that I might be lucky enough to attract a feral swarm.  If they find the bait hive an acceptable place to start a new home, they’ll move in and start building comb for the queen to lay in.  Here’s an image of one on a roof in East Buncombe County.

Our first run of grafted queen cells (where you remove young larvae and place them into special cups for bees to rear as queens) weren’t accepted by the cell builder colony.  They chose to raise their own queens instead, so we simply moved the frames with queen cells on them into mating nucs.

For our second round (grafted today) the cell builder now has no other appropriate aged eggs to use for raising queens so we’re hoping to have the easier to transport/share queen cell’s that we grafted ‘take’ and be ready in about 12 days.

Here’s a gallery of our queen rearing efforts so far this year: 

Carl Chesick demos honey bee increase with nucleus colonies or ‘nucs’

Last Sunday, Carl Chesick from the Center for Honey Bee Research here in Asheville, NC invited a bunch of volunteers who support his research to participate in a demonstration of making increase using five frame nuc colonies.


If you’d like to get in on invites like this while brushing up your hive management skills, sign up to volunteer here:


It was a great demonstration.  Some images and a summary of his technique can be found here:

And It’s worth noting that you don’t have to have four nucs going to make this work.  The inventory of frames needed for a successful split could all be pulled from a single strong colony.

One of the advantages of having 4 nuc’s like this to work with is that, constrained in a small space, the bees are continually in a ‘prepare to swarm’ mode, which gets them ready to rear queens.  It takes weekly monitoring to insure they don’t swarm, but this method works well for creating weekly new splits from 4 strong nucs.

I wrote Carl after the demo, as I had a few more questions and even after a long hard day at the office, he was gracious enough to more thoroughly summarize the technique he uses, and some of his philosophy around it.


———- Forwarded message ———-
From: Carl <>
Date: Tue, Apr 3, 2018 at 9:32 PM
Subject: Tired Take On “Five Frames”
To: Peter Brezny <>

The Nucs are about timing, and making them up from the correct slices (frames) of “time”. With enough nurse bees they can make an omelet.

(1) Frame of eggs. Frame APPEARS empty is covered with bees. These are nurse bees. Do this in late morning/early afternoon when most foragers are out. Nurse bees stay with the new nuc. Nurse bees feed the royal jelly. Nurse bees keep the cells warm.

(1) Frame of open brood (larva) with some capped. Bees on this frame are nurse bees. Nurse bees stay with the nuc. The presence of capped brood indicates the frame was laid earlier by the Queen. These bees will hatch in about two weeks – one week before those in the first frame.

(2) Frames of capped brood. These capped cells don’t need to be warmed by the nurse bees. They will begin hatching right away and ALL will hatch within ten days. They will be nurse bees. Nurse bees stay in the hive until they are approximately 3 weeks old.

(1) Empty frame, to give those 10 day old bees something to do with the wax they excrete naturally. Let them build comb.

The nuc will lose any foragers that get included. The Nuc DOESN’T NEED ANY FORAGERS – they have a bottle of sugar water over their heads. There should be enough pollen in the two open brood frames to feed the queen cells and finish out the open brood. There will be NO NEW EGGS for three weeks.
By the time pollen is needed the starting nurse bees will have aged into foragers. Within two weeks approx. 8,000 nurse bees will hatch. As the new queen is getting mated the larva/open brood will add 4,000 more. Finally, as her first eggs go into the cells the frame that was eggs adds 4,000 more nurse bees. The colony now has bees for each occupation and although it will be three weeks before her eggs hatch the colony has a considerable population to support expansion. Nucs done this early benefit from utopian forage in April and May.

I ENCOURAGE skeptics to carefully go in on day four to see how many Queen Cells have been started. There will be on average 3-6 cells. Be very careful in removing the frames as the cells will stick out from the sides. be sure to clear enough space and lift VERTICALLY very slowly. Also care in replacing. The day the nuc is made up is day 1. If the bees select the proper 12 hr. old larva they will cap that cell on Day 5. Anything capped before five days would be from too old a larva. If it takes 7 days to cap the cells, it means the bees waited two days for a particular egg to hatch.

If one notes the day the cell is capped, it will hatch exactly 8 full days from that time. I ENCOURAGE new Beeks to go in on that 9th day and determine HOW MANY of the cells hatched. These are distinguished by a smooth hatch-like opening at the very bottom. Cells which are torn on the sides DID NOT HATCH – but either died in the cell, were torn out by workers, or were killed by rivals. You might actually see the virgins lingering near the cells or hear them “piping”! On average three virgins survive to walk on comb.

Knowing how many potential queens are present is reassuring. It takes 3 days after hatching for the queens’ ovaries to develop. Then in the afternoons they begin mating flights. Several people have witnessed queens returning with mating sign at their rears by pulling up a seat at the entrance around 3 PM:) on the fifth day after hatch. It takes two days for the queen to mix and store the semen in her spermatheca and begin laying so the soonest the queen can begin laying is 5 days after hatch and on average it is about 10 days. In about 15% of the cases it can take two and a half weeks (17 days). Having the nuc open and apart when a newly mated queen is returning can result in her winding up somewhere else, likely where she’s NOT WANTED. For that reason I RECOMMEND leaving the nuc alone for ten days after queen hatch, but checking every 4-5 days after that. If there are no eggs/open larva 3 weeks after queen hatch, another frame of eggs can be inserted.


I think that ”don’t disturb them” mostly serves to keep beekeepers from developing the art of not disturbing them.