Winter Farming: Compost… Potting Mix… Sprouts!

Jan Wk 3 Sprouts - no heat mat!!

Things are really starting to get moving at the Market Garden.  Last week saw the first seeds sown into flats, and I am VERY pleased to report that the first Oak Leaf lettuces are sprouted!  And in only 5 days!!! These seeds were bought essentially on a whim – I had forgotten a packet at home and was at Menard’s for something else.  Seeing organic Oak Leaf seeds for $2 I figured wth?  That $2 will seed 4 flats of 200 -enough for a 3 x 60′ foot bed (spaced for small heads).  Not too shabby!    The 3 flats that have yet to sprout were planted with pelletized seed from Johnny’s – a Jericho Romaine and a  Red Butterhead.  They look to be 2 days behind the pure seed – likely due to the clay pellets needing more time to soak up water.

First lets talk about the compost heating method.  This is the same pile we started back in the first week of December to mimic Growing Power’s techniques in using Hoop Houses to allow for 4 season composting.  At home, my piles, even my monster 4 bin system, freeze solid by Christmas.  Will Allen’s Hoop Houses cut the wind and gain enough btus during the day to stay hot all winter.  Our pile is still truckin along at 120-130 degrees without turning and is going on week 7.   having that kind of heat is dang useful.   So when the time came to start my lettuce for the cold frames, rather than unroll the 12′ heat mat, I scraped the top of the beds flat and nestled in 4 flats of lettuce.

800 lettuce transplants - heated by thermophilic bacteria

The two scraps of lumber are to prop up the greenhouse plastic I keep over it at night to lock in the heat from the pile.  This will stop once the rest of the flats germinate as its wicked humid in there and mold is already creeping in.  Mold.  In January!  Here is a “proof” shot of the soil temp under the flats.  This is a 24″ compost thermometer run horizontal under the flats.

87 degrees (air temp outside 22, inside 38) - yep that should do it!!

A bit more on the compost pile.  While we haven’t fully turned it, we have primed it a bit.  Every week we add about 10 gallons of material by digging a hole in a section and pouring in two buckets of gorp from the coffee shop.  We then cover this will about 4″ of leaves.  As the pile dries out we shovel snow onto the top and this seems to be keeping it nice and evenly moist.  The worms are loving it – we are seeing our first hatchlings now which is super exciting.  The wigglers move around an amazing amount in search for the conditions they want – the right mixture of food, temperature, acidity, and moisture.  Its super fun to try to guess where they have moved to on any given day.

The compost pile has been used for the past months to melt and heat all sorts of things.  First off, we buried two 55 gallon drums in the piles while we made it.  The thought was that we might need to heat the barrels with the gasifier to keep the pile warm enough for the worms.  Yeah Right!!  The pile has since heated the water up to as high as 110 degrees, and is still at 102.  If you have read any Jean Pain, you will be thinking what we are – if you can get 55 gallons of water to 100-105 degrees, you can make methane (stay tuned on that one!!).  A few weeks ago I went and dug up 5 cu ft of soil from one of our compost planting beds.  These beds are the end product of 10 years of composting municpal leaves on the farm.  The most mature bed is about 50×50 and is pure leaf compost (decade old) for about 18-24″ deep.  It is GORGEOUS.   I took a pick axe, hacked through the 4″ of frost and excavated a wheel barrow load of this compost/soil for my seed starting mix.  That soil was really dang cold and had chunks of frost in it, so I filled up some 18 gallon tubs and tossed them on the compost pile.  3 days later they were all thawed out.  Awesome!    Today I decided to take the time to make a Big Batch of seedling mix, and managed to take some pictures.  I am not real finicky – I basically take 3 parts compost soil to 1 part peat moss and then soak it down with a thin fish emulsion mixture.  Before I add the water, I sift the mix twice (1/2″, then 1/4″) to make it very fine.  The flats I am currently growing in were unsifted – this batch is for soil blocks.  Here is my sifter which was built by the farm owner:

Slick system - the sifting boxes are stackable which makes for quick work about 1 cu ft every 5 minutes

The top tray has a 1/2″ grate on it  and is nested on top of a 1/4″ screen.  Both are simply hardware cloth screwed to the bottom of the frames.   The Sifter frame is 2×2 pine with 2×4 bracing around the top.  The plywood is 1/4″ and provides alot of stability.  The internal “chutes” allow for a reduction in the sq footage so that a rubbermaid or some other container can catch the product.  Because they are angled, you still have enough room on the top for a good push/pull stroke.  I built one of my own at home and sized it to drive my smaller wheel barrow under it and skipped the nested sifters, opting for only the 1/4″ – though if I were to do it again I would compromise for 3/8″ in the name of speed.  The results?

"Junk" compost. This is typically put back into the compost pile.

Yes, this is even better in real life. GORGEOUS!

The peat moss gives it fantastic texture and prevents the mix from drying out.  I have some conerns about the peat moss – its not exactly renewable.  At the same time, one bag gets me enough to do something like 1-2 yards of potting soil which will let me grow upwards of 2000#s of food.   Next season I will have a shredder for the Grillo and will try to grind up some leaves into ittty bitty bits (shredder comes with a 3/16″ screen)to mimic this and will do a side by side.   Leaves are more readily decomposed, so those little bits may tie up nitrogen.  Time will tell.  In 30 minutes I made about 5cu ft of potting mix.  As is usual with home made products it should prove to be superior to store bought.  Why?  The compost soil I used was never pastuerized to kill “harmful” organisms.  That means that my seedlings will be living in a rich soil food web of bacteria, fungi, protozoa, and worm casings (which will hatch alone with the seeds!).  All in all it was a great few hours on the farm.

Happy January!



13 Responses

  1. This is incredible stuff. Thanks for posting.

    Are you familiar with coir? I wondered what you thought of using coir instead of peat? We’re going to use it in our rooftop containers this year. Hope it works out.

    Until recently, I haven’t been able to find a bulk supplier that would ship to me in Chicago at a reasonable price. Rolanka’s coir costs the same as peat, shipping included.

    • Thanks Bruce! I am familiar with Coir, Will Allen buys it by the truck load for his operations. Like you I have been concerned about the cost. That is a good price, but at $75 per bale it is $64 more than the bale of peat moss I am using ($11.50 at Ace here in the hinterlands – that is a good price even for here). This year I am keeping much better financial records: it may be that even that price premium would be negligible when stretched over the thousands of starts. Coir comes with a 5000 mile foot print, peat takes millennia to make. I really hope that the leaf option works next year.


  2. Could you post a diagram of the sifter?

    • Sarah, I will see if I can get some better pics. We will also be making a kick ass compost tumbler this year out of bike rims, hardware cloth, some angle iron for a frame and a 1hp electric motor. The goal is to be able to sift out worms from the vermicompost with 90%+ accuracy so I can sell the castings.

  3. Fascinating idea of winter composting! I’m still experimenting with different seedling mixtures using charcoal, pine bark, and urea. Do you have a paper mill near you? Mine will give tons of pine bark for free. Acta has more:

  4. Speaking of mills: Do you have access to wool waste in your part of the world? It strikes me as a theoretically good additive for potting mix, because it decomposes so slowly and is nitrogen-rich. I think the shorter fibers that are rejected during spinning etc. would be about the right size.

    Sweepings from a barber shop might also be worth looking into, although they might have to be washed and chopped.

    • Another idea along similar lines is ground up feathers. Not feather meal, which has been hydrolysed to speed decomposition.

      Another additive worth considering is a source of mucilage. Psillium husk has been used to good effect, but I think fenugreek flour might also be worth considering. Papers I have read have suggested tiny amounts, since this sort of thing swells so much in water.

    • Last idea: sycamore trees are dropping fruit everywhere, and their fibers look useful. I’m going to try pasteurizing some to kill the seeds, and seeing how well they do as a soil amendment. I bet they’re available locally for most urban farmers, too!

  5. […] air temp was 21 with a steady 12 mph wind – easily enough to kill spinach and kale, let alone the lettuce I have in mind for this cold frame.  Wind is the biggest issue in winter.  If you can keep temps […]

  6. your compost is awesome. I am a very lazy composter – I just shovel out the barn (straw, with a nice blend of horse, goat, and chicken poop) and pile it high, then pretty much leave it for six months or so. I am kind of wimpy and can’t really turn it over as much as I’d like with just a pitchfork, so I aerate it by using the pitchfork to poke holes. Just today I dug in and got some of the older stuff from the bottom of the pile – it looks okay, but it’s a little too compact and uneven. The parts where I dumped all the apple-mast from last fall’s pressings are still kind of slimy. And I’m sure I don’t get anything like the temperatures you do. I think we get way too much rain here, the pile is soaking wet most of the time. Most likely I should tarp it in the winter.

  7. Have you considered coconut fiber (coir) to replace the peat moss? I’ve found it to be a similar texture and way easier to wet initially.

    • I have, but I would need dozens, and dozens of blocks and the cost is prohibitive at this point. Frankly I am not enamored with either option – peat is not renewable, and coir is outside my definition of local by about 8400 miles. That said, using the (relatively) small amount of either to make thousands of pounds of food is a net gain and I will continue to use them until I can make or find a local, renewable alternative.

      That said, I am hoping that some mixture of finely shredded sunflower/corn stalk, leaves, feathers, etc that many of the commenters have mentioned will do the trick.

      • One more odd idea, inspired by Emilia Hazelip:

        You might try filling your trays with leaf mold as-is or with very minor additions next autumn, and then using them over the course of the winter to grow a polyculture or a succession of micro-greens, chosen for what their roots bring to the table.

        Maybe a seed that exudes a lot of gum, like chia, to improve the moisture-retention of the mix. Perhaps a legume that’s quick to form nodules, or just has seed with so much protein content that its roots contain more nitrogen than they absorb. And perhaps most importantly, a species that produces extensive, fibrous roots, to improve the loft and strength of the potting mix…maybe some juice bar would pay for hotbed-sprouted wheat grass?

        Then, after the final micro-green harvest is over, the improved trays will all be available to start plants for Spring.

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