Tuesday, January 1, 2013

New Climate

Growing Cymbidiums back in the DC region had its challenges. The summer nights were hot and humid. The winter lows were too cold, necessitating protection either in a heated greenhouse or being brought inside the house and kept under lights. Below is a graph of the 2012 temperatures from a weather station closest to my previous home. Heat- and warmth-tolerant Cymbidiums grew well outside for most of the year; whereas, the cool-growing Cyms melted in the summer heat.

Now that I'm back in San Francisco, one would think it will be much easier to grow the Cyms. However, San Francisco has a multitude--by some reports over seventeen-- of different microclimates, illustrated below.

My simple goal for the Cyms since their move is to just survive and produce new growths. Most are complying, but I think I've lost two or three plants. For myself, the goal is to learn about my new microclimate and its changes throughout the year. Below is an equivalent graph of the 2012 temperatures per the weather station closest to my present locale. You can see that the temperatures are fairly even throughout the year. Given that my local temps infrequently go above 70F, I no longer have a strong need for heat-tolerant Cymbidiums, and I'll be curious if my existing heat- and warmth-tolerant Cyms will flower for me in their new environment.

I think the more challenging variable is managing light levels due to the abundance of fog. The graph below illustrates how much light levels change from day-to-day. If I lived in one of the sunnier microclimates just east of my home, the April thru August daily light levels would average about 2000 to 3000(!) watts/m2 higher. The peak above 8000 watt/m2 in early June represents a sunny day, and indicates just how much light I'm losing to the fog the rest of the summer season.

Below is a graph of light readings on a sunny day: a nice smooth curve. Such a rare occurrence here.

Below is a graph of light readings on a foggy day. You can see how variable the light levels can be throughout a single day.

Here is another example of a foggy day, with the fog burning off late morning, but yielding a foggy afternoon variably interrupted with sunshine.

Here the fog burned off late morning and yielded a relatively sunny afternoon.

It is going to be a challenge to provide adequate shading for the Cyms when they are exposed to direct sun but also allow for sufficient lighting when under fog. There are already some sun-burnt leaves here and there while I find the right balance of shading and the plants acclimate to their new environment.

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