Sunday, January 10, 2016

Ten Below Zero on the French Riveria

We woke to a temperature of -10 degree Fahrenheit this morning here in Minnesota. It has been relatively mild until now and this is the first severe cold of this season.

It is no surprise to the hardy Scandinavians settled this area that we would have this kind of cold. We often see -20F or even -30F earning us a Zone 4 designation on plant cold hardiness scale.

We had a 12 inch blanket of snow two weeks ago so all the fall planted garlic, onions and even parsnips are settled in snuggly for the winter. Snow is an amazing insulator, and will modify the climate near the soil by 20-30 F (as it protects the plants from icy fingers of cold, and facilitates the grounds natural +40F temperature percolating upward near the surface. If the cold snap is brief we may hardly have any frost in the soil.

Snow also transmits a significant amount of light. Snow grains are strongly forward scattering in the wavelengths that the plants need and it is not unusual for photosynthesis to continue at levels high enough to sustain plant foliage under the snow. Thus frost hardy spinach will be mushed down (a technical term meaning to be flattened against the ground). But still green and lush. In fact the plants will often boost chlorophyll production to compensate for the lower light conditions, so the leaves may be darker green than normnal.

Many of the "locals" do not realize that South East Minnesota is at the same latitude as the southern coast of France. WHAT, how can that be. The French Riveria is a mild climate European hot spot for vacations. Yep, check it out, a  google search or a quick look at any old globe will confirm these facts.

In our next post we will explore why this matters.

No comments:

Post a Comment