A short entry by work-learn student Tamara Bonnemaison today. She was also the photographer.
Last week I woke up to the first frost of the year, and decided it was the perfect time for a morning stroll through UBC Botanical Garden. Walking through the Food Garden, I was reminded of the feeling of surveying my small farm after a frost, feeling at once relieved that the busy season was over, and disappointed at the loss of income that a frost represented. Now that I am a student, I can walk through a garden and focus instead on the pattern of ice crystals kissing the edges of leaves, and wonder at the biology that allows some plants to withstand freezing while others succumb at the slightest dip in temperature. This celeriac, Apium graveolens var. rapaceum ‘Ibis’, looked like it was only gently touched by the frost, and the knobby stem will remain delicious for many cold months.
Celeriac, also called knob celery, is a type of celery grown primarily for its flavourful knobby hypocotyl (stem below seed leaves), leaves, and roots. It is cultivated in temperate vegetable gardens and farms around the world, but is most popular in Europe. Celeriac requires a long growing season, and the taste of its gnarly-looking stem sweetens after a frost, making it perfect for wintery dishes such as these recipes for remoulade and soup. I haven’t yet tried these, but they look particularly delicious.
Celeriac has a number of the qualities that allow it to survive and stay tasty in cold weather. A report by the FAO discusses frost physiology in common vegetables, and Apium gravoeolens var. rapaceum exhibits a number of the traits that the FAO lists as ways that plant species tolerate cold temperatures. For example, the large, fleshy stem has a high heat capacity, preserving the day’s heat well into the night. Also, the entire plant is able to gradually “harden” by increasing concentrations of solutes such as sugar to lower the freezing temperature of its tissues. All that is to say that it is very convenient that starchy root vegetables such as celeriac achieve their peak late in the season, just in time for the thick soups and comfort foods that feel so good to eat in the winter.