Latitudinal Thinking for 4 Season Harvesting

-8 (-22 C) air temp, but crystal clear early morning sunshine streaming through the windows. Steel cut oats simmering on the stove and the kids, animals, and I snuggled up reading on the couch in this first hour after dawn.  Perfect morning to be reading about growing food every month of the year in Coleman’s Winter Harvest Handbook.  I live in Wisconsin.  As this morning so aptly depicts, it gets wicked ass cold.

But what is so vital to be able to get one’s head around is that temperature can be dealt with through slight modification of environment and very careful selection of species. ** Sunlight is the key **.  And that is where latitude – the “sun lines” come in.  I am at 43 degrees north.  That is way up there, right?  Follow the line around the map to Europe and be amazed.  Nice and Marseilles, France.  Florence, Italy.  Monaco.   Shit – I am further SOUTH than Milan, Turin, Bordeaux and Venice.  Of course they get a massive benefit from the Gulf Stream, but there is plenty of sun 9 months of the year to grow a huge variety of crops.  And from November – January (Coleman’s “Persephone” months) when the day length is under 10 hours, spinach, mache, claytonia will still grow if the temp is kept above 20 degrees or so and they are started early enough.  Crops like leeks, kale, carrots, etc can be harvested fresh from the soil from covered spaces (even mulch) in a condition and quality far superior to any root cellar.

As those who track the blog on Facebook know, In the coming weeks I will be building a 12×30 unheated Hoop House in the backyard.  And while it will be unheated, you all know me well enough by now to understand that this will be far more than a sheet of plastic over a garden bed.  Details to come.   I am never going to grow ‘maters in January, but the potatoes and onions in the cellar will go a helluva lot further on the table when augmented by FRESH carrots, leeks, after a crisp, nutrient dense salad of fresh picked greens.  In Wisconsin…  in January.  I have a dream – and its already proven, so its just a matter of building the system and learning the skills.  Permaculture is far from only being about fruit tree guilds and nitrogen fixing under-stories.  It is about finding sustainable ways to feed our society and build capacity for future generations.

Of course, growing under plastic is a transitional technology – plastic is made from oil.  But there are brutally hard truths about the coming decades – those 8-9 BILLIONs of people aren’t going to be fed on our current ag systems as oil gets more expensive– and we have a moral imperative in the first world to get our shit together and stop mining the soil of the developing world to feed our fat asses.  If you are worried about the embodied energy of the plastic consider the facts – it last for at least 5 years with care and used intensely can allow for 3x the harvests from the same amount of space.    Far more important – the additional yield is during the times of the year when most of us are importing almost all of our produce.  If the energy and moral sides don’t sway you – then the added resiliency of your own food supply might.  With careful planning it will be possible to walk out my backdoor 365 days a year (again – in Wisconsin) and pick meals worth of produce fresh from the soil for my family.

I will ever be one to embrace technology and tools to help us transition to a better future if those transitional tools meet my criteria; I will break eggs to make my permacultural transition omelet as I muddle through to find solutions to the problems of our age.

Be the Change.


If you would like to purchase the Winter Harvest Handbook and are not able to do so from a local bookseller, consider clicking through this link to buy a copy.  Proceeds will help us with our work being the change.  This is something I will be doing more of, though I promise to do so only for books that have profoundly influenced my planning or thinking.   Coleman’s book is insanely helpful on this topic – I have read it at least 4 times cover to cover and reference it several more times a year for my planning.
The Winter Harvest Handbook: Year Round Vegetable Production Using Deep Organic Techniques and Unheated Greenhouses


29 Responses

  1. Do we really want there to be 8-9 billions mouths to feed? I though the over-riding opinion was that the human carrying capacity was somehwere around 1 billion.

    • The population of the earth is a fact at 6+ billion – and the 8=9 billion is almost a certainty given the demographical inertia across the globe… your question is out of line. “Intellectual” arm chair debates about the “carrying capacity” of the Earth are bullshit and worse than wastes of time. I chose the words “moral imperative” very specifically. As ethical people in the current age we must do what we can to feed those currently alive and/or cease actions that prevent them from doing so themselves. What we want or not is mute as the 6 billions are alive now – of course the carrying capacity of the earth is far lower than our current population if we don’t have cheap energy -for transport, fertilizer and medicine. Any educated person knows that – we saw food riots with a 25% increase in oil and we have a billion underfed NOW.

      The potential reality of the next 50 years for the majority of the 2nd through 4th worlds –including the un-rich in the 1st worlds– is beyond our conception. Grandstanding, finger-shaking, and “I told you so” arguments are reprehensible in the potential reality of billions watching their loved one’s starve.

      The real question is: what are you and I going to do about it?

      Be the Change.

      • That’s quite a good keyboard lashing. It wasn’t really meant to be downer point but I guess in retrospect it was. Perhaps I get caught up in humans disappointments.

        I agree that getting the skills and creating systems now will make the future much more bearable. I’ll be doing my part fo that this year as well.

      • Thanks for replying Syd. If I misread your intent I apologize for giving you both barrels. We’re in this together.

  2. Rob,
    Is snow build-up a problem for your hoop houses?
    If it is, how and how often do you have to remove it?

    • Build-up on the north side is a good thing for insulation – on the south side I expect to see 2-3′ depending on snowfall based on the snowfall shed off the sides of the larger hoop houses on farms around here. Shoveling may be necessary 1-2 times a year on the really big events to make sure I am not losing too much sun.

  3. Hi
    I have Four Season Harvest, by Coleman, and didn’t know whether this new book had much that was not already covered in the first.
    Have you read ‘Solar Gardening’ by Leandre and Gretchen Poisson?
    It is also about season extending, and has some interesting ideas, and plans.

  4. Rob- I am also learning to grow under cover. Arugula did very well for me under plastic, with lows of 20F.In summer it bolts, in the winter I just keep cutting it back and I would even swear it grows even in december/january. Cilantro held but didn’t grow. Lettuce (brown golding from Wild Garden Seeds) looks crappy on the outside but might be OK on the inside. I am going to start fertilizing with pee. Collards look good but the slugs do like them. The collards under plastic are larger than the collards with no protection.

  5. Only -8 some parts of Wisconsin are here in Zone 4a it was at least -15. How Does the Winter Harvest Handbook compare to The 4-season harvest By Coleman?

    • I read 4-Season several years ago, and before I thought I would ever be doing it. I remember that I found it inspiring, but its been too long for me to compare them without a re-read. Winter Harvest is amazingly detailed – he goes so far as to give you cultivar names, planting spaces, and dates for planting (you have to modify for your climate of course). He shares seemingly everything he’s learned with a candidness that is striking and in a style of mentoring that is endearing.

  6. This part says it all: “Permaculture is far from only being about fruit tree guilds and nitrogen fixing under-stories. It is about finding sustainable ways to feed our society and build capacity for future generations.”

    Right on!

  7. having run a couple of simple 12×30 unheated hoops the last couple of years it is a joy to behold. last week we had 4 inches of snow and zero temps for a few days. Then this week after most of the first snow left another 2 to 3 inches. Wimpy by the true North Standards but, My point. is I went in the hoop house last night after a sunny day and it was damp and moist and oh so Spinglike.
    Mache and Spinach are real troopers even is zero and below temps. In my hoops last year the Mache hunkered down and looked like it was frozen but, once we hit 15 to 20 degrees with some sunshine it was up and running. So was the spinach.
    Like Rob said it doesn’t have to be all hoop houses either.
    I’ve seen folks in Michigan digging carrots from under heavy mulched beds and a foot and a half of snow. It’s not only possible it’s really exciting.
    Love Coleman’s work very inspiring .

  8. I’m going to keep supporting my local Zeitgeist Movement and continue to expand my knowledge on all things related to the ideas presented by Jacque Fresco and the Venus Project. 🙂

    • Taking steps in a positive direction are very necessary. I am not overly familiar with Fresco, nor his Venus project, but I like his focus on conserving resources and working towards a more sustainable future. At the same time, I have issue with his strong undercurrent that there are plenty of resources and energy for all, and that technology can save us.

  9. Hey Rob – great post. Somebody asked about snow load, what about wind? Here in NEOhio we get loads of both. I’ve read Coleman’s book and have collected 3 sets of plans for hoophouses but am worried about wind damage. Looking forward to seeing your design. Also (probably getting ahead of your upcoming posts) do you plan on moving the hoop house around like Coleman does?

    Thanks for all of the great work you are doing!


    • Tim – Wind is only an issue if two (well three) things happen.
      1) – wind lifts the structure
      2) – wind is able to work the plastic loose and get it flapping
      3) – wind causes a structural failure in the hoops

      My answers:

      1) – each hoop will be literally bolted to two posts sunk 2+ feet into the ground. That should be plenty.
      2) I plan on using wigglewire around all the edges which will greatly reduce the risk of the it flapping loose. I may opt for a 2×2 strip with the plastic folded over and then screwed into the footers on one of the sides to save money – the other side will have wiggle wire to allow it to be re-stretched and tightened once it gets warm. Most issues come in here when the sides are just laid on the ground and covered with soil/sand bags, or if cord is wrapped over the top like in the Johnny’s catalogs. If bungee cord is used it is self tensioning, which is good. If cotton is used, the cord stretches which is bad. I will have framed end walls which also help in this regard.
      3) I pan on having 3 “purlins”, which are essentially a ridgepole, and two extra poles running the entire length of the hoop about 2-3′ off center. These are clamped onto the hoops and provide very rear lateral rigidity. This structure will go “Aunty ‘Em!” long before it caves under wind load. One ridge pole would be fine for structure – the other purlins are wicked useful for trellising ‘maters and cukes and I have some other things planned too.

      I plan on moving the structure this fall to get it into the bed it belongs in once the garlic is out and the summer crops are done. But after that it will be semi-permanent. This is by design as I will be installing some bells and whistles that are far beyond the “cold houses” Eliot uses – it will be far closer to a greenhouse by next winter with its insulated north wall, active solar thermal heating system, 2 yards of compost, and 3 yards of vermicompost – perhaps with rabbit top feed manuring add-ons. It is possible that I will get so much into it that it will not move until the plastic needs to be re-skinned in 2017 or so.

      Hmmm… when I actually write that out, it seems silly to not put it right where I want it just to save 100 heads of garlic…


  10. Good post. I don’t begrudge the use of plastic for hoop houses. I plan to use it myself. But you are correct to point out that it is a transitional solution. I wonder what – if anything – will take its place when we’ve completed the coming descent. I have to admit the possibility that nothing will, eventually. That doesn’t mean that we shouldn’t use it as a tool for the short term. No doubt by practicing season extension with this tool, other strategies will suggest themselves as our skills and knowledge develop. I do see cold frames, limited though they be, as one possible successor technology to hoop houses. There will be storm windows and scrap lumber around to salvage for a very long time to come. I look forward to seeing what else clever gardener-inventors come up with.

  11. Thanks for your explanation. I know that the ridgepoles will be a necessity. A guy down the road from me built a Coleman-like (unheated) hoophouse and even with one or two (can’t remember) central supports had it partially collapse on him under a load of wet snow. His new design features multiple center supports.

    If possible, we’d like to get one built this next year – don’t think it will be quite as mobile as Coleman’s. Also, I’m thinking it would be a fine place to let the chickens run around in the winter on occasion?

    Again, thanks for your detailed explanation. As always, looking greatly forward to seeing what you come up with!!! One final comment – your opening description of sitting in the wee dawn hours reading with your kids while is great – needs only one addition …. a woodstove! Keeping thinking about it, you won’t regret the addition of one.

    • Tim – the woodstove will be in by next November. Coppice is on order. 🙂 It will not be an easy retrofit – have to put in a full chimney- but its is very, very high on our list of things we need. Our home would be unlivable in under a day at current temps without the grid. That is unacceptable.

  12. Nice post, thanks for recommending that book! Year round veg harvesting has been a goal of mine for a few years now and I’ve yet to get as much going as I’d like, so I’d be very interested to hear more about what this guy’s got to say.

    The latest thing I’ve been trying for winter veg is a heritage seed company over here in the UK called ‘real seeds’. They produce really good, hardy seeds, lots of them bred by small producers living in cold countries so they’re better adapted for growing through the winter than a lot of the more popular veg varieties. Do you have this kind of company over in the States? Something I really like about this company is that they also encourage you to save your own seeds so that gradually, after numerous years of doing this, you end up with veg that is perfectly adapted to your particular conditions. Nice!

    Anyhow, I’m rambling, thanks for the great post!

    • Nancy – you Brits are crazy far north, so the trick will be to get a large amount of seed sown in August to be harvestable size before your days get to be too short for growth. Then it will be a matter of keeping them alive, which will be far easier for you than me, and will make up for the shorter days to some extent.

      We have nothing like the seed restrictions you have with the EU – my preferred source for garden seed is the non-profit seed exchange, Seed Savers. For farm seed I go with the seed cooperative ofFedco.

      Heirlooms and saving your own will absolutely net you massive gains over time – my garlic crop is unreal after only 3 seasons of selection.

      • Thanks for the tip (the august thing). And yeah, you’re right – most winter veg I’ve tried will survive here with just a little fleece protection or nothing at all. Be nice to experiment with some less traditional winter veg though to see how far you can stretch the rules. Carrots? Beetroot?

        Getting them in soon enough to be big enough to eat is not my strong point though! Let’s just hope the extra mulching this year keeps those weeds in check so I’ve got that little bit more time to play with..


  13. Rob – you will soon be addicted to all things related to woodburning! I highly recommend the forums on

    Great place to read stove reviews and get advice on installation. For pipe and associated installation materials I recommend:


    Both seem to have the best deals on installation supplies. You seem like a very handy guy and could manage the installation yourself. Just be safe, follow NFPA guildlines, and stove manufacturers requirements on clearance. Safety must be paramount! A side benefit will be a nice ash supply for the compost pile, around the fruit trees, and for the strawberries. I officially put in my request now to see the results of your efforts 11 months from now.

    Best Regards,


  14. Hey Rob
    Nice stuff here.
    I do have a couple questions about the effect of winter there. Here in high altitude Colorado, our winters are certainly different (much drier for starters, so no snow for insulation) but not all that dissimilar. In past year’s experiments with protected winter growing here, I have had the ground freeze gradually creep into the greenhouse beds. But Coleman suggests in the book that the freeze never makes it past the boundary of his cold house. My previous winter garden structures were smaller, particularly narrower, than what he is using, so I wondered if that was related. I know that at your market garden plot you have varying sizes of hoops, and was wondering if you have noticed any difference in the “protection” aspect afforded by the larger hoopties. Does width in particular aid the maintenance of soil temps?
    We are looking to install our own multipurpose hoopty this year for next fall/winter and are planing on going larger anyway, but was curious if you had found a width that seemed to be the right number, say 12 feet or 16 feet. We do plan to include a large compost pile- part of the reason to go bigger- as well as overwintering some chickens which would provide body heat as well. Both those aspects were missing from previous experiments, and should help. Of course I would like to avoid discovering after the fact that we should have gone 2 feet bigger….
    Also a follow-up to your vermi efforts. I was thinking of starting a vermi-project here, partially buried like yours, and was wondering if that had enabled your worms to survive the cold. I know some folks here who lost all theirs, of course they weren’t earth bermed at all.
    Look forward to the insight and the future posts.

    • Ecofarmer,

      On the smaller hoopty at our Market Farm (11′ wide) I saw frost creep in about 4″ on the sides. We typically have 6-12″ of snow cover much of the winter though. I would recommend at least a 12′ width and then take the extra step of a heavy mulch around the south, east, and west sides (I recommend the long axis be as close to E-W as possible. More on that in a minute). I typically buy straw in the fall when it is readily available and line the sides of my hoop house with them 1 row deep. On the south side I break the bales and lay it out to prevent the 18″ tall bales from shading overly much. If you are using raised beds it is less of a big deal. Leaves also work great for this. This will limit the frost depth around your hoop house.

      The other problem is that it sounds like your average temperature is dropping too much and you may need more thermal mass. I put 150 gallons in my hoop house last winter and it froze as much as 1-2″ on top so at some point it was acting to stabalize temps, but due to the average temp being below freezing it was stabilizing them too LOW. Your Compost idea sounds like a much better one, and one I have used in the past to good effect. If you have a large enough structure, and enough compost material, combine the two – bury 55 gallon drums of water in your compost beds. I have kept 110 gallons of water over 80 degrees for 2 months that way in large houses (26′ w x 72 long) when there were set in a 4 yard compost pile (4′ deep/tall 10 or so feet long).

      If you place your hoopty on the E-W axis then you have more space along the inside of the north wall to soak up heat (compost is dark). Also OUTSIDE your hoopty along that long north wall, layer up as much snow, or even better, leaves and manure, to compost all winter and act as an insulating berm. Watch your structure – you may need additional bracing. Will Allen does this to great effect at his farm in Milwaukee.

      Finally, placing an inner layer such as a low tunnel from Johnny’s will raise the temps of that area by 8-15 degrees overnight while also raising relative humidity. Both are a huge asset in the winter.

    • Oh – on the chickens – careful about ammonia emmsions from their manure. It will can harm the plants and potentially raise the nitrite levels in your greens. Make sure they have copious amounts of carbon rich bedding to balance the manure and don’t stock too many. I do not think either of these issues would impact overwintered carrots IN the ground and “on hold”.

  15. I wouldn’t worry too much about the use of plastic. Trying for perfect is a great way to make zero progress at all.

    I know I posted here before, but I wanted to let you know we just got our half acre in suburbia and I’m trying to get the materials together to build a Jean Pain style pile- and I wouldn’t have ever heard of him if it wasn’t for you, so thank you. My yard is going to be proof of the ripple effect that you started.🙂

    I find a lot of great material on Craigslist, and now I’m keeping an eye open for glass panes from old windows. They show up cheap or free regularly enough that it’s worth looking for them. I’m planning on building a cold bed for us to keep us in fresh salad greens over the winter, but the Free Heat project (building aluminum can heaters, and a couple of painted-black roof mounted water heaters connected to an underfloor radiant system) will get first crack at the glass.

    I also find old windows for a good price at our local Habitat for Humanity ReStore, though that tends to be more expensive than CraigsList.

    • Coleman did a nice calculation on oil in the hoop house plastic vs. oil used to ship lettuce from California to Maine. I don’t have the exact figures in front of me, but it was a very clear savings to grow in an unheated plastic hoop.

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