Wednesday, November 20, 2013

Building a Cold Frame

The month of October was swallowed whole by family matters. First my father-in-law passed away and then seventeen days later my mother-in-law slipped quietly away in her sleep. They were always good to me... to us all and I find myself tearing up just typing these words.

For me, one of the ways grief expressed itself was a terrible tiredness that made me want to avoid anything routine; including the computer, the internet and blogging. It has been weeks since I posted anything. 

Slowly, slowly I am slipping back into the comfort of old familiar habits. Now I find myself looking forward to catching up with good friends.

Wow! I can't believe it is already mid-November and fall is almost over!

The big Maple at the back of the garden always seems to be fall's swan song. It is the last tree in the yard to turn color and finishes the season with a crescendo of most brilliant yellow. 

Then there is frost and the Maple leaves fall like rain.

Last week hubby took some time off and we busied ourselves with completing a number of ongoing projects including this cold frame.

I first became interested in cold frames a couple of years ago. 

I was amazed and inspired to see how gardeners like Brenda (Gardeningbren in Nova Scotia) managed to extend the gardening season with the use of a cold frame.

Niki Jabbour, The Year Round Veggie Gardener

Niki Jabbour's blog The Year Round Veggie Gardener was also a real eye opener. 

Who wouldn't be impressed by that picture of Niki kneeling beside a cold frame in the dead of a Canadian winter?

Needless to say, when her book The Year Round Vegetable Gardener was published, I bought a copy.

Last fall hubby and I came up with a design to transform one of my raised beds into a cold frame. 

If I had a bigger garden, I probably would have built a permanent cold frame, but space in our backyard is at a premium and so I wanted to design a structure that could be a cold frame in winter and revert back to an ordinary flowerbed in summer. 

Here you can sort-of see the four raised beds last spring. (Oh how I now wish I had taken better pictures of this part of the garden last spring!) 

Overall my garden is a bit of a jungle, so I like the little bit of order and formality that the raised beds provide. 

There are lilac standards in the centre of two of the flowerbeds diagonally opposite from one another and...

decorative plant supports in the centre of the opposite pair. 

Hopefully next spring clematis will be clamouring up the plant supports and covering them with flowers about the same time that the lilac standards are in bloom. Fingers crossed anyway!

One raised bed holds my collection of herbs (as seen above). In another, I grew tomatoes and strawberries last summer. In the final two beds, I planted a mix of flowers.

Here we are in November.

Last year we constructed the sides of the box which transforms the one of these raised beds into a cold frame. Being busy, we ran out of fall before we could make the top. To get us through the last winter we ended up borrowing a few old windows from a neighbour. 

Last week, we finally completed the project and made the top doors.

The smart part of this cold frame design is that it takes less than an hour to transform the raised bed into a cold frame. You simply fit the cold frame sides into position and attach the three doors. (We store the component pieces in a shed during the summer.)

For purposes of demonstration, here we have detached one of the cold frame sides to show you how it all fits into place. In the shot above you can hubby fitting one of the sides into position to complete walls of the frame.

Because the sides fit together like a puzzle no nails are required to hold them in position. Any one of the side walls can be removed in a matter of minutes.

The final stage of the fall transformation from raised bed to cold frame involves the installation of three plexiglass doors.

It remains to be asked: why go to all this bother? I can think of so many good reasons:

A cold frame is certainly more affordable than a buying a full greenhouse, yet offers many of the same advantages. 

It also takes up a lot less space than a greenhouse and is the great option to consider for a small backyard.

As I indicated earlier in the post, a cold frames allow you to extend the growing season in a number of ways. 

My herbs are still going strong despite the fact that it's mid-November and we have had several killing frosts. And last spring the herbs sprouting new growth over a month ahead of the rest of the garden.

You can also grow a winter crop of vegetables in a cold frame (visit Niki or Brenda's blog for inspiration). 

Like a greenhouse, I found a cold frame to be a great place to start seeds. 

I have limited space in the house for seedlings. Last spring I was able to start some seeds inside the cold frame as early as late March/early April.

Rose Mossy Saxifrage, saxifraga x arendsii rose selection

I also found that the cold frame is a great place to park tender plants for the winter.  Thanks to the shelter it provides, the top of this birdbath planter came through the ravages of a Canadian winter beautifully.

Sometimes I have trouble over wintering Mediterranean herbs like thyme, but last year I had no problem with the most of the plants inside of the cold frame. (The exception were a few thyme plants that were right in the corners. There are some very small gaps where the structure fits together and they were big enough to allow cold drafts to sneak inside and affect the plants right in each corner.)

With under an hour to make the transformation, I have to say that I am rather proud of how easy we have made it to use a cold frame each fall and winter.

For more project details please see the Cold Frame How-to.

Cold Frame How-to

Here is the plan drawing that we used for the four raised beds:

The basic raised bed is 7' x 4' and is constructed using 2 x 12 cedar boards with 4 x 4 cedar post in each corner (Note: Cedar is one of the best choices for wood that will be in contact with soil).

Pine sides fit into position like a jigsaw puzzle to transform the raised bed into a cold frame each fall. (Note: The cold frame box does not touch the soil and so we opted to build it with less expensive pine.)

Here you can see a photo showing all the sides in position without the obstructed view with the top in place: 

Because the sides fit together like a puzzle no nails are required to hold them in position. Any one of the side walls can be removed in a matter of minutes.

The final stage of the fall transformation from raised bed to cold frame 
involves the installation of three plexiglass doors.

1. Here you see the first completed cold frame door in position. We opted to use plexiglass for the doors rather than glass because it is not as breakable. Also for amateurs like us, plexiglass was a lot easier to work with! 

We were able to get readymade plexiglass panels (30" x 60") at the Home Depot which were almost the perfect size. We just had to shorten each plexiglass panel by 6 inches.

The door frames were made using four pieces of 1 x 2 Pine. To construct the door frames cut 2 x 54" lengths and 3 x 26.5" pieces (the competed door width will be 30").

2. The construction of the doors is very basic. Simply screw L-brackets into place at each corner of the door. The window's centre support bar is held in position with a metal T-bracket at each end. Then finishing nails are added at each corner for extra stability.

We designed the plexiglass panels to sit on top of each door frame rather than being inset (as in a standard window frame). We wanted any rainfall or snow to be able to slide cleanly off the surface of each door.

Now place your plexiglass panel on top of the frame and clamp it into position. You need to cut off the extra 6" overhang. Using a T-square and an Exacto knife score the plexiglass along the outside edge of the frame. Hubby carefully scored the line 6 times to ensure a good clean cut. 

4. Grab a scrap of wood and place it along the inside of your scored edge. Now press down on the overhang and it should snap cleanly free.

5. Attach the plexiglass to the frame with 3/4" #8 Robertson screws (3/4" Phillips will work just as well). We placed a screw approximately every 6.5".

 Just a couple more steps!

6. Now attach a handle to the centre front of each door. We used an inexpensive 5 3/4" handle.

7. On the back on the cold frame attach each door with two 3.5" T-hinges approximately 6" in from the sides of each door. These T-hinges are the one semi-permanent part of the cold frame that will have to be removed to dismantle the cold frame each spring.

Condensation on the inside of the plexiglass doors provides plants with moisture. 

The cold frame is not heated of course, and so during the winter it will get cold in there, but the enclosed structure will always be much warmer than the surrounding environment.

And the Winner Is...

I am sorry about the long delay in announcing a winner for the Fine Foliage book draw.

The book's publisher St. Lynn's Press has graciously given me a review copy for this giveaway. To assist me with the draw I recruited my son Daniel (that's his handsome hand in the next photo).

And the winner is....

Alana whose blog is named All is Amazing.  Congratulations Alana!

Alana, I will be in touch with you shortly to get your mailing address. I am sure you are going to find lots of great inspiration in for next spring in the pages of Fine Foliage.