We returned to our cold frame on White Mountain Peak to make repairs, improvements, and spring plantings
We almost didn’t make it. A late spring blizzard had dumped a foot of fresh snow on the site earlier in the week. By the time we got there the sun was shining and the snow was melting.
The frame was a little beat up from the winter. Part of the hardware cloth rodent-fence was torn off, and the middle window frame was warped and ajar.
A surprise awaited us when we opened it up. The plastic garden thermometer in the right chamber (the one that was sealed tight) had melted! It looked a lot like one of Salvador Dali’s clocks. When we checked the data logger in that chamber we learned that the temperature had exceed 185 degrees F. As Matt pointed out, water boils at that temperature at this altitude! No wonder nothing was living in this chamber. So, we learned that ventilation on hot days is crucial.
Fortunately, we came prepared for this. We replaced the left and central chambers with windows that have much stronger frames and better ventilation systems. We also added analog minimum/maximum recording thermometers and a gravity-fed drip irrrigation system with a 75 gallon capacity.
The data loggers also recorded high temperatures of 165 degrees F in the middle chamber and 112 degrees F in the chamber that had no window glazing! The last measurement was simply impossible to believe. Belatedly, we realized that all three of our blue plastic data loggers were exposed to the direct rays of the sun. They had given us readings that were too high.
How could we have made such a simple mistake? But, live and learn. We build little sun shades for our data loggers out of reflective bubble wrap.
Most of what we had planted last August in the middle chamber had sprouted and started to grow, but it was all dead now. Or was it? A close examination of the brown tufts of winter wheat revealed green blades. We left the winter wheat to try to recover in its new cooler and moister environment. We also planted radishes, assorted salad greens, marigolds and a variety of potato called “Alaska Frostless.”
What we learned:
- Extreme heat is more of a problem than extreme cold. Ventilation is the key to success. It got so hot in the sealed chamber that water would have boiled.
- Nothing grew in the unsealed chamber, so the window glazing does help maintain an environment suitable for plants.
- We have to keep our thermometers and data loggers in the shade (we ought to have known that.)
- We don’t seem to have any trouble with rodents.
- Our MicroDAQ data loggers worked great.
- All three chambers recorded approximately the same minimum air temperature (-5 to -9 degrees F), so we need some way to better heat or insulate the chambers on cold winter nights.
- Winter wheat shows promise for a fall planting.
Our work done (for now), we enjoyed campfires at the University of California’s Crooked Creek Facility (elev. 10,000 feet) and went for walks in among the bristlecone pines. We’ll be back in September if not sooner.