With a change of winds in the forecast (north to south winds) and the tomatoes becoming seriously root-bound, a risk was taken with transplantation to the outside world (May 21). They wilted for the first day or so, likely complaining primarily about the drastic drop in soil temperature they experienced (i.e. 20 °C to maybe 5 to 10 °C). A cold frame was built consisting of the old windows used in the
Cold Frame #1 experiment to help warm up the soil and protect them at night. In hindsight the cold frame should have been constructed a few weeks in advance to pre-warm the soil (note to self for next year).
Note Kale & Brussels Sprouts on the left (transplant from generous neighbour) & Lovage in the center (in above photo). Peas and Swiss Chard are just starting to break the surface (can't see in this photo).
Part of the experiment was to test the cold frame in frost conditions with a sensitive plant like tomatoes. Frost was predicted that night, so last minute scrambling resulted in blankets and tarps over the windows and a 60W bulb placed inside to provide a heat source (a method used successfully by my aunt). I had plans to put a fan inside as well to circulate the heat, but due to limitations with the extension cord and time, only the light was used in the end.


The tomatoes survived the night with a frost of about -1.4 °C according to
Environment Canada measurement at the Calgary International Airport. The Middle Earth Garden is about the same elevation as the airport and within 4km or so. So the airport temperatures are likely a good approximation for now.
A high-low recording thermometer is on the list of items to purchase for future experimentation. If anyone can recommend a thermometer please let me know. All the ones I've seen so far at Canadian Tire are battery operated digital and I'm trying to find a non-battery type. Searching just now there is one at
Lee Valley. I have not been there yet as it is a bit far by bicycle. I suppose a digital thermometer with an indoor alarm for low temperature might be handy too, maybe establish trending into the computer... OK maybe too high-tech for this low-tech garden operation!