Tuesday, March 20, 2012

Raised Bed/Cold Frame Aagaard Farms' Style!

North side, high side.
We've been talking for a couple of years about building cold frames and raised beds.  Both have big advantages for extending the season - a boon in our cold Manitoba climate where our last frost date is June 6th and our first Fall frost date is September 9th.  Yes, that's right - we've got four months to grow everything.  Manitoba has been known to get snow in mid-June and we've gotten frost as early as August 21st!  It's a good idea, especially if you grow vegetables for a living, to have protection, back up plans so to speak!  To that end, we've had great luck with our hoop houses or high tunnels over the last few years and we do plan to build a second this year.  After we fix the first one....again.  Even with a heavy-duty plastic cover, the hoop houses are prone to winter damage from the weight of snow and high winds.

Cold frames are in-ground beds with a glass or plastic cover.  The glass cover creates a solar affect, heating up the soil inside faster than the surrounding ground.  Seedlings are protected from wind and excessive moisture, the soil retains some heat in the evening and they'll provide some degrees of frost protection if the temperature dips or it snows.  If electricity is available, soil warming cables can be put in the bed to ensure good night-time temperatures!  As daytime temperatures increase, the glass covers can be opened or moved to keep temperatures at a reasonable level, then returned later in the day.

Raised beds are beds built above the existing soil.  They can be constructed of various materials and you can pretty much choose your height.  They can be built over soil that is of questionable quality and filled with a rich, nutritious mix.  They also raise the working area - a bonus for bad backs for both weeding and harvesting.  Raised beds have become popular features in retirement communities where, with a solid walkway, even people in wheelchairs can continue to garden.  They are also really useful in urban areas where they can be constructed over concrete or really depleted city soils and be really productive.  They are also visually appealing, providing some variance in height.  We've seen beds built of natural stone, old brick, reclaimed chunks of concrete, lumber and timber.  If growing food in your raised beds we would highly recommend avoiding treated wood of any kind, including railroad ties!

So, Farmer Man has been reading and thinking on these things for a couple of years.  When a neighbor offered free small bales of straw, Farmer Man saw an opportunity!  This being such a mellow winter, the snow has already melted from the area he had in mind.  He'd been thinking about an area along our front driveway, close to the road.  It's an area of poor soil, prone to erosion.  He started by discing the whole area to chop up last year's plant debris and loosen up the soil.  He next used the tractor to take one scoop of soil to create a mound.  You see, cold frames should be oriented south, to catch maximum sunlight!  He started the frame of the bed, in straw, on the mound, as the high point and back.  He then continued to lay out bales until he had a rectangle, lower in the front, south side.  The opening is about seven feet long and three and a half feed wide.  He then filled the bed with a screened mix of our own two year old compost and well-aged manure purchased last year from the Research Centre.  The opening was then covered with some old windows he had stashed.  He weighted down the windows, just to be safe.

All this just happened yesterday, two beds were created.  I went searching today for a spare thermometer and got it in place, on the shady side, so we can monitor the temperature over the next few days to get an idea of how these beds are working.  The straw bale construction is certainly being tested today, as we've had winds all day of 35 kph with gust to 55kph (about 24 mph with gusts to 40 mph)!  If temperatures seem reasonable, we'll probably start by seeding some lettuce and maybe some onions early next week!  We'll keep you posted!


  1. Replies
    1. A compilation of ideas from sources such as Elliot Coleman, Lewis Hill, Mother Earth News, Small Farm Canada and many more!

  2. I've been reading an awful lot about cold frames too lately. Straw bales apparently work very well, especially for taller crops. I checked my raised beds this evening to see if I could get working on them but they're still solid as a rock. Adding a cover to those beds so I could plant a little earlier would certainly be helpful to get a jump on my veggies.

    1. Raised beds are supposed (!) to warm up faster. Are you still really frosty?

  3. What a fascinating idea. Its amazing the innovations that can be really be done quite cheaply.