Ghetto Fabulous Cold Frame: a Photo Essay

The owner of the farm I rent my land at is a Master Scrounger.  Scrap steel, fiberglass molds, barely working engines, and barrels and tubs of all sizes lay around in somewhat organized disarray.  Last year I helped him restack a few dozen 3’x6.5′ panels of tempered glass from a retail store front and have been waiting for this day ever since.  My vision?  A Ghetto Fabulous, monster sized, uber cheap cold frame.  Step one started, as do many of my harebrained ideas, on Craigslist.  I found a guy 5 miles from here with 100 bales of oat straw for $2.50 a bale so yesterday I motored over with my TDI Golf, trailer in tow, to load up.  17 bales fit oh so nicely, and with the ground frozen solid I was able to drive right up to the mini Hoop House.

This is why I don't drive a Prius... 42mpg pulling 800#'s of straw!

Once the straw was on site and chucked over the fence it was time to start breaking ground.  With the recent rains we lost over half the snow, but the resulting ice proved to an issue.  The top 2″ of soil were not fun to break through, but below that was frost free.  The plan was to scrape free the snow below the bales so that they rested on bare soil as much as possible.

I opted to use my wicked tough 4" Rogue Chopping Hoe rather than a pick axe. The first few swings needed a lot of wind up, but then progress was steady.

I intended to lay out the bed on an East – West Axis, again to minimize shadowing, with the beds about 5.5′ wide and at least 15′ long.  The width of the beds was determined by the length of the glass, the length of the beds is to avoid the shadow from the tree wind break located 30′ to the west, and I want to avoid the footprint of the planned 26×72 Hoop Structure to the East.  Here is a shot about 25% through the job (30 minutes) with the layout taking shape:

The soil dug from the foundation is piled into the bed.

You can see that there is alot of soil being moved.  This is entirely on purpose for several reasons.  A bale of straw is well over 12″ tall and casts a heck of a shadow in the low light angles of mid winter.  So I sunk the south run of straw about 4″ into the soil.  This, combined with the natural south slope of the plot makes for about a 5″ drop over the course of the cold frame.  That is good, but I want better.  For every 5 degrees of slope you gain about 125 miles of latitude to the south.  So the soil from the excavation is piled into the beds, and once melted, will be “leveled” to give additional slope to the interior of the frames to maximize solar heat gain.  Finally, the black soil will reduce the Albedo Effect of the white snow reflecting the heat to further increase internal temps and hasten the melting of the snow and frost in the frame.

The cold frame is really taking shape. 6' of glass bows a bit without support so I reused the bamboo stakes from '09's tomatoes for bracing.

Some of the glass no longer had their frames and were bowing more than I thought prudent.   Luckily I had kept the 6′ bamboo poles I used for tomato stakes last year and they worked fantastic.  Time on farm at this point was about an hour and change – much of that spent lumping glass which was stored about 100 yards away.  I’ve had more fun than walking that far carrying 60# plates of glass over icy ground  in winter winds…  But it was worth it:

Viola! about 70 sq ft of cold frame in under 2 hours.

The straw cost $40, but will get used at least 4-5 more times (mulch for potatoes, then squash, then shredded for compost, then fed to worms, and their poop put into 2011’s cold frames🙂 ).  I realize that few people will have 6-7 panels of tempered glass just laying around, but salvage windows, storm doors, etc are remarkably common if you keep your eyes open all year.  Will it work?  Well with one panel still to go on, no loose straw chinked into all the gaps, and the thermometer literally resting on frozen soil, the interior was registering 46 degrees as I laid the last panel on.  Outside 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 over 20 (25 better still) you can grow a remarkable amount of food if you shelter the plants.

This cold frame will hold  250-300 heads of Romaine.  Early lettuce will command $4-6/lb, which means that my straw and $2 in seed will net a profit of several hundred dollars for my labor.  More importantly my family will be in for fresh romaine in less than 3 months.  Awesome.  Next week I will build another (got 4 blisters today that need to heal), and may put a small one in the hoop house for kicks.


20 Responses

  1. rock on! That’s awesome! I’ve been keeping an eye out for old windows for a while but haven’t scored any.

  2. For years my parents had some glass sitting in their basement for a slider… makes me wish it was still available. Where did you find the calculations about efficiencies?

    • Which efficiencies Ryan? The planting rates and yields are based on my own experience, the temp readings from a cheapo thermometer from a hardware store. I almost never run real calculation on my gardening projects. The energy ones get *MUCH* more analysis – mostly because I am never afraid of a cold frame exploding…

  3. You must be my long lost brother ….

    near the bottom of the post you can see my diesel jetta and my trailer with a giant haul of straw.

    my wife has wanted to make a cold frame for a number of years, we replaced most of the windows in our house this fall, so i see a straw bale / window cold frame in our future. we will blog when we get it done. thanks for sharing the way.


    • Eric – it is almost eery how similarly our minds work. I would like to think that we are reaching the same inevitable conclusions based on the available empirical evidence. *Of Course* one would drive a TDI as they are the only game in town if you need to move 5 people and tow 2400#’s while getting well over 40mpg, still have a 5 Star Crash Rating and get it all for under $7000 used. They are the vehicle du jour for the suburban generalist. I will likely be augmenting mine with a 1 Ton dump truck (to be run on methane), and I already have a mountain bike converted to street duty for in town travel (I taco road bikes –not a very subtle rider curbs are for jumping, yo!).

  4. That is excellent – I have seen this concept in books, but never anybody trying it for real. Awesome.

  5. Wind Chill was -9 today with air temps in the single digits. Cold Frame was at 47 degrees by 11am. Awwwww yeah.

  6. Fantastic! I think straw bales must be some of the most all around best double functional items in the world. BTW just found your blog and love it!

  7. Hey Eric:

    Long time. Amazing what 10 hours of daylight can do. Greens start growing again, chickens start laying. It’s like 60 degrees, seeds germinate, compost composts.

    One of things that we wanted to work with in our greenhouse was phase change materials, but to do this you need alot of sunshine in the winter, something we don’t have. I have found folks out in CO that were doing something with it, but not for greenhouse gardening. Some folks came up with some really good ideas but they were all patented. Well those patents have expired. They worked with materials that melted at low temps, like glauber salts, and then at night as they “froze” up again released their heats. Until now the patents hid the missing ingredients. We are stuck between Binghampton and Ithaca NY, the two cities with the least amount of sunshine in the US. If you have sunlight during the winter, this might work for you. Let me know and I’ll send you the info.


    Lucky Dog Farm

  8. For the past few weeks ever since a warm snap, we’ve seen lots of tracks in the snow and tunnels under the snow.

    Won’t mice love the free room (straw) and board (lettuce)?

    • Oh yes, very much! Voles are actually the bigger problem and my mini hoop house is invested. Eliot Coleman spends more time on vole control in his latest book than he does on how to grow his Candy Carrots. Trapping is a fact of life, but one “trap” in this structure should do it. I have a post that is just waiting for picture uploads detailing the Vole Hotels I built to Coleman’s plans. They seem to be working: better success in 2 days than my previous attempts in 2 months.

  9. What about a barrier on the outside of the straw bales right down to the bottom of the bales?

    • Voles are going about 8″ down to get under my portable hoop house rails and they will go through the bales. With the structures in the middle of a field an earlier start to the trapping I think I can contain them as it will be an isolated population. This population bred on me and it got silly.

  10. Joel, a few years ago when I saw some chickens catch, kill and eat a frog I freaky out. Us city slickers have a steep learning curve! The voles go into the compost piles and seem to get preferential treatment by the bacteria and macro fauna thanks to their concentrated fat and protein. 2 weeks and they’re husks. Fur/bones takes longer.

  11. […] progress at the farm.  Dropped 70 transplants into the GFC (Ghetto Fabulous Coldframe).  They are mostly oak leaf lettuce.  Its at least a week early, but the frost is out of the soil […]

  12. I love the idea … but was wondering how you get into the cold frame to tend or harvest the lettuce?

    • Its a bit of a hassle – getting the glass off is not overly hard – just slide them down. But the cold frame is almost 6′ wide with 18″ sides so you really have to step into it. A 3′ wide bed with a shorter front would work much better.

      That said, I have 150 lettuces thriving in there right now despite night temps in the teens, and it was essentially free, so I am not complaining!

  13. […] fast.  Remembering that I have two old patio door windows, and seeing this post a while ago at One Straw, I figured it was time to build another cold frame.  I scored these windows a few years ago after […]

  14. Probably not so necessary now but add some milk jugs full of water to stabilze the temps on cold nights and get an even earlier jump on the growing season!

    By the way it doesn’t look ghetto to me…looks practical!

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