In the Garden:
Southern California Coastal & Inland Valleys
December, 2003
Regional Report

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Plastic or fabric sheeting can be placed on top of this woven framework on frosty nights.

Frost Damage Protection

The sun's light and warmth slip to the year's low ebb this month. Evening chill is barely offset by warmish days. My average hard frost period is Thanksgiving through January 31, although my garden hasn't had any real damage in several years. Consequently, I have four-year-old pimento peppers bearing fruit from August through February! Since we never know whether we'll get temperatures down into the low 30s or high 20s, however, we should take some precautions in the garden. Here are some to consider.

Change Watering Habits for Winter
Continue to water your overwintering outdoor plants unless the rains keep the soil moist. Irrigation should be reduced, not stopped, as plant photosynthesis slows down and cold weather dries plants out. Plants that are stressed by lack of irrigation are more susceptible to frost damage.

If you're unsure whether your plants have enough water, dig down a foot or so; if the soil's not moist, water. However, plant and tree roots are not very efficient in moving moisture throughout their systems during cold weather, so be sure they aren't waterlogged.

Knock down water basins around trees and plants to lessen the chance of sitting water and the resulting root rot. Loosen the soil within the basins so water can penetrate more easily.

Cover Up
Protect citrus from cold damage by wrapping the tree trunks in newspaper and covering the foliage with old bed sheets. Cold soil and dry winds can cause the rinds of ripening fruit to develop bleached blotches, and leaves to turn yellow where the sun strikes.

Protect the the southwest sides of plants from chilling winds with plastic sheeting. Be sure the plastic doesn't touch the foliage. This can literally conduct the frost to the foliage since it doesn't have its air-envelope protection.

For overnight protection when frost threatens, cover bougainvilleas, fuchsias, hibiscus, and other subtropicals with large cardboard boxes, or drape old sheets or tarps on stakes over them.

Move container plants next to, but not touching, a south- or west-facing wall so plants can absorb reflected daytime heat but are shielded from winds. Move dish cacti and succulents and potted trees under cover for protection from cold and rain.

Remove mulch from under trees back to the drip line. The bare soil can then more easily absorb the day's heat and release it to the trees at night. This also discourages overwintering of disease-carrying bacteria and insects.



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