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Light in the winter garden

We in Northern California are fortunate to live in a climate that enables us to garden all year. Our moderate temperatures enable many vegetables to grow through the winter, and at most lower altitudes, frosts are rarely severe enough to kill resistant plants and vegetables.

Newer gardeners often find their gardens less than successful, because they don’t consider another factor which is as important as temperature: sunlight.

'The Real Dirt' is a column by various local master gardeners who are part of the UC Master Gardeners of Butte County.
‘The Real Dirt’ is a column by various local master gardeners who are part of the UC Master Gardeners of Butte County.

Sunlight warms the soil, and retained heat minimizes the effects of below-freezing temperatures. Sunlight warms the plants themselves, and provides the light energy that enables the complex chemical process of photosynthesis.

The problem of sunlight for winter gardeners is that there is simply less of it. Everyone knows this, but too often we don’t consider it carefully when planning or planting a winter garden. In summer, one must often think about protecting plants from harsh, direct sunlight.

In winter, plants must be placed where they will be exposed to the maximum light available. In winter, not only are the days shorter by several hours, but the sunlight strikes the earth at an indirect angle, thus transmitting less energy for heat and photosynthesis.

In Butte County, on June 21, the longest day of the year, the sun at noon rises to almost 75 degrees above the horizon. Today, Dec. 21, the shortest day, it rises barely 25 degrees above the horizon. In addition, the December sun rises not in the east, but near southeast; it sets near southwest, not in the west.

Compared to other seasons, the winter sun rises later, describes a much lower arc through the sky, reaching barely a quarter of the way to the zenith and

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