A Simple, Cheap Cold Frame for Growing Veggies in Cold Weather and Season Extension
homesteading·@sagescrub·
0.000 HBDA Simple, Cheap Cold Frame for Growing Veggies in Cold Weather and Season Extension
As of last fall I am a firm believer in the power of season extension! I have been experimenting for the first time with low tunnel hoops. You can read about what has worked and what hasn't [here](https://steemit.com/homesteading/@sagescrub/cold-hoops-poly-low-tunnels-for-fall-season-extension-a-successful-experiment) and [here](https://steemit.com/homesteading/@sagescrub/cold-hoops-mid-winter-update-more-insights-from-the-poly-low-tunnel-experiment). Some money out of my pocket, several handfuls of hours of effort and I learned a lot. ## But season extension doesn't have to be costly or complicated. I want to share with you an example of how a cold frame can be hobbled together with resources you already have or that you can easily scrounge up on Craigslist for free or very little money, especially if you start looking for those resources now, well ahead of next Fall.  I'm not claiming this is the most beautiful cold frame but it sure didn't take a lot of planning or resources to put it together. The farmers here used some extra old weathered wood that was sitting around and some translucent sheet of fiberglass as a cover.  ## Why a cold frame? I'm going to refer back to Eliot Coleman. When I read [The Winter Harvest Handbook](https://www.amazon.com/gp/product/1603580816/ref=as_li_tl?ie=UTF8&tag=sagescrub-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=1603580816&linkId=7434c810eff0877ecc258eff20562a7a) last fall it transformed the way I looked at growing in the shoulder seasons. Actually it shaped the way I look at it because I had no idea what was possible. This book is highly recommended if you want season extension with your veggies. I took away a lot from this book but the one thing that Eliot burned into my brain is that with one covering of your veggies you gain the equivalent microclimate of 1 1/2 zones warmer. With a second inner covering you gain another 1 1/2 zones warmer for a total of 3 zones warmer! How amazing is that! Here is a direct quote: *"When you enter the protection of one of our cold greenhouses, you can take off your parka because the microclimate you encounter is that of a location approximately on and one-half USDA zones to the south. When you reach your hand under the row covers you have moved another one and one half zones south where the Main winter definitely does not prevail. Outdoors the climate is Zone 5; under the inner layer, the climate is Zone 8."* Eliot goes into detail about his experimentation with different materials inclding different types of poly (polyethylene) hoop covers, different spun-bonded row cover fabrics (e.g. agribon), cold frames, etc. He did a lot of research for us to take away some of the most efficient use of materials. ## The important thing is to get your crops covered with something translucent or clear. For now, I've ignored all the specifics about the most efficient materials. I focused on the fact that one covering gives me 1 1/2 zones warmer microclimate!  So the combination of this cold frame inside this greenhouse is approximately 3 zones warmer. Well I'm pretty sure we didn't acheive the maximum efficiency Eliot did. But it's pretty darn good for a hobbled together cold frame. Note the bricks that hold the cover down to make a better seal and to help keep mice out, if any show up. Hopefully not many [thanks to the cats](https://steemit.com/homesteading/@sagescrub/working-cats-on-the-homestead-helping-control-the-gopher-mouse-and-rodent-populations). In the above photo check out all the snow piled up on the side of the greenhouse which is adding extra insulation.  It's really easy to take the bricks off and lift off the lightweight cover. The frame itself is also lightweight and easy to move. In this case the wood we used is rather thin and light. That might be part of the consideration for the design of your cold frame.  As you can see it doesn't take an engineering degree to put together a simple cold frame. This one won't win any design awards, but it works and that's the first priority on this farm!  ## Now this is the exciting part for me! See those little sprouts? Those are lettuce sprouts from the seeding I did in late October after weeding out the greenhouse. We decided to seed some lettuce, onions, austrian snow pea cover crops and a few others expecting that we'd get a head start on spring planting and that they would start coming up in early spring. Well it turns out we got even more head start than expected because many of the seeds have germinated and little sprouts are there sloooowly establishing themselves well ahead of spring. Don't get me wrong, they won't do much until it warms up a little more. But we might be harvesting lettuce as early as late march or early spring. WOW!!  This is also testament to the ability of these two layers (greenhouse + cold frame) to carry some cold hardy veggies straight through the winter if you had the foresight to sow your veggies in late summer or early fall. And you could have fresh greens, onions, and roots all winter long. I should also note that the soil in the greenhouse is not frozen, and it's definitely not frozen in the cold frame. This is while the ground outside has been frozen for almost a month now.  I pushed up soil and mulch around the sides of the cold frame on the outside and inside to reduce airflow and help keep the box insulated. ## I also would recommend strategic placement of your cold frame (or greenhouse or hoops). Try to avoid placing it at a low point where cold air can collect so that it doesn't get colder than it has to. Think of cold air like water, flowing through channels and valleys.  For example you can see from this photo that the veggie bed the cold frame is placed on is higher than the pathway. This is partially due to building up the soil with compost and mulch and partly due to the pathway being compacted from frequent walking while the beds stay fluffy since we avoid walking on them as much as possible. ## Even 1 or 2 inches higher than the low point can make a huge difference being a few degrees warmer. You can use slope and terrain to your advantage, creating "berms" or channels of earth, rocks, other terrain or structures for air to flow around your cold frame or greenhouse. Cold air flowing past your cold frame would be better than cold air pooling next to or above your cold frame. Walking around the greenhouse it was also exciting to discover that the onions, spinach and other greens - some planted and some volunteers - have started coming up already. Well ahead of our target of early spring germination :P  ## So to recap * One cover can give you 1 1/2 warmer zone microclimate while 2 covers can provide 3 zones warmer microclimate! * A cold frame design can be as simple or complex as you want * This simple cold frame was free, easy to hack together and nearly immediately available to use. * There are some tradeoffs to the simplistic design (in our case none of these mattered but they might for you): ** There is no hinged cover so venting or accessing the inside is slightly less efficient ** The cold frame is not angled so you can't take full advantage of a lower winter sun ** Aesthetics might be lacking, depending on *your* point of view! * Eliot Coleman is the man when it comes to growing shoulder season and winter veggies. Consider checking out [The Winter Harvest Handbook](https://www.amazon.com/gp/product/1603580816/ref=as_li_tl?ie=UTF8&tag=sagescrub-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=1603580816&linkId=7434c810eff0877ecc258eff20562a7a) or any of [Eliot's other excellent books](https://www.amazon.com/Eliot-Coleman/e/B000APSTD0/ref=sr_ntt_srch_lnk_1?qid=1515291361&sr=8-1&_encoding=UTF8&tag=sagescrub-20&linkCode=ur2&linkId=4c70010ab47463b8979358b407a0990f&camp=1789&creative=9325). * Consider craigslist diving to find resources to build your cold frame. * The exact material of the cover is less important than having a cover in the first place. You could use any translucent or clear material including plastic (such as polyethelene or other clear plastic), fiberglass, discarded or unused windows or sliding doors, other glass panes. If this post inspires your future project, please let me know how it goes! I'd love to learn from you :)
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