Part 1: Building The Cold Frame
I blame my Dad for my creative stubbornness. If I can dream it, I must be able to build it. He gave us full reign of the tiny workshop in our basement and let me tell you, I created many a pieces of furniture out of his wood scraps. They weren't very functional, but I could create anything I imagined. I still operate under that premise. It doesn't always turn out right, beautifully or even as what I originally intended it to be, but it always teaches me something...and pushes me on to my next experiment.
So this fall, inspired by an article in the Hobby Farm magazine and an old sheet of glass, I embarked on a cold frame experiment. I sorted out scraps from my husband's piles of wood, built a frame around the glass and set to work.
You should know that I'm not big on following rules, using plans or even measuring things (this is how I cook, too). As a proud ENFJ, I do a lot of "eye-balling" and following my gut. The organic process feels more exciting when I succeed and more educational when I fail. Call me crazy, but that's how I'm wired. So here is the rest of the story in pictures...
1. DIG THE HOLE - I picked a spot in the backyard where it gets direct sunlight for most of the day and dug a hole about 10 inches deep.
TIP: Always over-estimate the dimension in case you discover enormous roots, rocks or things that make you have to shift a bit one way or the other.
2. PUT IN THE FRAME - I built four walls and assembled them one at a time inside the hole. I used random scraps in a very simple design and chose not to weatherize.
TIP: Weatherize the wood that will be in the ground - paint, tar, or some kind of protection is good to make the frame last longer.
3. BODY COMPLETE - I originally intended to paint the body, but once I got going I grew to like the look of the bare wood. We have fairly mild winters in Arkansas so I decided to take the risk of not painting it. Most cold frames are built with a slanted roof to maximize sunlight. I wanted to experiment with a lazier option so once it was assembled, I tilted the entire frame forward and pushed dirt in the back to secure it in place.
TIP: Painting the frame black will help to keep it warmer and protected from the elements.
4. STAPLE ON TRASH BAGS - I used four heavy-duty trash bags - one for each side. Hang the bag over the frame so that the bulk of it is on the outside. Secure them with a generous amount of staples leaving at least an inch of the bag on the interior edge.
TIP: Hang the bags upside down so that the staples go into the seamed - strongest - edge of the bag. It also lets the air out more easily.
5. INSULATE WITH BAGS! - I was having a hard time trying to decide what to use for insulation when I spotted a huge bag of plastic grocery sacks. Once upon a college Spirit Week, my roommate and I dressed as twins wearing plastic Old Navy bags. Let's just say I was VERY warm on that cool autumn day... So trash bags won this insulation contest. I layered them in thick using a staple gun, starting at the bottom and working my way up. As I worked my way around the sides I could already feel the temperature beginning to rise.
6. INSULATION COMPLETE - I broke a sweat squatting inside this thing on a chilly day so that was encouraging. It took two large black trash bags full of sacks to cover the inside of this frame - which is roughly 4x3x2 feet.
7. FLIP THE BAGS - Say goodbye and good luck to the plastic bags as you flip the black trash bags over into the cold frame. It doesn't matter if the trash bags go all the way to the ground or completely cover the plastic bags - this just helps to insulate and creates a nice surface for the soil to rest up against.
8. CREATE A LIP - Cut boards to fit the top edges and secure them in place. This hides the trash bags and all your staples. Make sure this lip creates the proper size window to support the piece of glass that will go on top.
9. FILL THE FRAME - There are all sorts of recommendations about how to fill a cold frame. I took the compost route in hopes that the plants on top would benefit from the natural heat being created down below. I just used what I had in the yard plus some borrowed (aged) manure from these cattle I know. I started with a few sticks for aeration, then layered in carbon and nitrogen sources until it was over half full. On top of all that I put in a mixture of soil from the yard, finished compost and a bit of sand.
TIP: Manure is great for adding nitrogen to compost piles, but I've been told that it should have about 90 days to rest before you plant any edible crops on it.
TIP: If you do the compost method, fill it up extra full to account for the shrinkage that will take place as it does its thing.
10. ADD THE GLASS TOP - I used two hinges on the back to secure the framed glass in place. I also added an L-shaped piece molding (using 1 inch finishing nails) on the front edge to create a bit of a surface for easy opening.
11. PLANT! - Once the glass top is secure and the body is full of rich soil, plant your seeds. I mostly experimented with a lettuce mix, cabbages and kale but planted a few beets and carrots just to see how they did.
12. WATER - Once the weather gets cold, try not to open the frame. I read that watering once a week would be sufficient, but I discovered that it was definitely not enough. Give it a good long soak.
TIP: Try to water early on a sunny day so that the frame has the rest of the day to warm up again.
13. EXTRA WARMTH - For really cold areas, you should look into hooking up some sort of heat lamp and thermometer to regulate temperature. Without a heat lamp and temps in the 30's, my cold frame maintained temps in the 50's and 60's depending on the sunlight. I used a blanket to cover the top of the frame on nights when I knew it was going to get below freezing. We got hit with a massive snowstorm on Christmas Day. Thousands of trees suffered damage - including the large pine above the cold frame. Luckily, no damage to anything on our property. And the greens in the cold frame looked fresh and perky through it all. |
| A photo of the largest seedling through the steamy glass. |
Overall, I think this experiment was a success.
January 2013
Part 2: Cold Frame Face-Lift
On February 1st I decided it was time to give the cold frame a face-lift. The soil and compost had compacted so much that light was only reaching a small strip of plants in the back. Because these plants were doing well, it seemed worth it to take the time to improve the living conditions of all of the plants in the cold frame.
I started by carefully removing all of the plants from the frame. Then I added soil until it was about 6 inches from the top. I was amazed at how much soil it took to fill the frame. The biggest seedlings were then replanted with more space to mature and the smallest seedlings were transplanted into the greenhouse. It's not quite two weeks later and the plants in the frame have doubled in size. The ones in the greenhouse are perking up a bit, but haven't had the same kind of transformation.
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| Here you can see how drastic the face-lift was. |
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| 10 days later, the plants are showing rapid growth. |
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