Regional Gardening Reports :: National Gardening Association

In the Garden:
Northern California Coastal & Inland Valleys
June, 2010
Regional Report

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Cymbidium orchids respond to cool night time temperatures and regular fertilizer.

Cool vs. Hot

Do you realize how lucky we are to live in California? I have just returned from a visit to my mum who lives in North Carolina where the weather was a sticky 88 degrees. I can't imagine working outdoors in that kind of heat, but I guess our bodies can adjust to anything, given enough time.

Plants can also adapt to an unfamiliar environment to a certain extent. The reason beefsteak tomatoes don't do well here is because our nighttime temperatures are too cool for the big tomatoes to develop, as opposed to areas in the south where it stays warm all night long.

Extended periods of high temperatures increase the rate of reproductive development. Pollen development is also triggered by heat. In other words, it takes heat to set fruit. That's why it is inadvisable to plant your tomatoes too early in the season. Cool evening temperatures will inhibit a warm season plant from growing. Those big, meaty beefsteak tomatoes take a long time to develop the sugars and acids that make them so yummy. Luckily for us, there are hybrid tomato varieties that thrive without constant high temperatures, 'Early Girl' and 'San Francisco Fog' for example. 'Big Beef' is a hybrid that seems to do well in the inland valleys and will perform well with some night time chill.

High night time temperatures in the south and along the east coast are important to the native plants of those regions. On the other hand, cool night time temperatures are vital to plants indigenous to mountain regions. Take the cymbidium orchid for example. Here in the west they are hardy and grow like weeds, blooming year after year with a minimum of care. It is not our pampering that makes them so successful, but the cool evening air. You couldn't grow a cymbidium where the nights are hot unless you had a climate-controlled greenhouse.

Cool season annuals are more sensitive to hot weather than warm season annuals. Pansies, nemesia, sweet peas, Icelandic poppies and snapdragons are examples of plants that thrive in cool weather. The damage from heat on cool season plants is done on a cellular level. I know just how they feel... On a hot day it sometimes seems that you just can't drink enough water to keep yourself going. Plants are the same; the roots can't pull water fast enough from the soil to supply the leaves with the necessary moisture to keep up with evaporation and transpiration. The result is that the foliage wilts. This is why it's so important to know if a plant is suited to your particular environment. If you are unsure, ask your nursery professional.

This past winter I fertilized the potted cymbidiums with whatever I could find, which included some fruit tree fertilizer spikes, intended to be pounded in the ground around the drip line of apple, peach and cherry trees. I broke each fertilizer spike into three or four pieces and set a chunk in each potted cymbidium. In mid February the flower spikes began to form on the plants. By March they were blooming furiously and now, at the beginning of June, they are still going strong. Was it my magic touch with the found fertilizer or was it the cool spring temperatures? I don't know for sure, but I'm glad to be living where the nights are cool. I think the cymbidiums are too.

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Today's site banner is by nmumpton and is called "Gymnocalycium andreae"