January Gardening Tasks


Franklin Laemmlen, Ph.D., Master Gardener


Author’s Note:

January is a fairly quiet month in the garden.  So far this winter the temperatures have been cold.  I have checked with a few long-term (native) residents of Santa Maria, and am informed that this is a cold winter as winters go on the Central Coast.  Cold is both good and bad, depending on what you are trying to accomplish.  The cold should help reduce and suppress insect populations, diseases will not be active, and weed growth will be prevented or at least greatly slowed.  All our fruit trees will get a good chill this winter, which bodes well for a good fruit production season in 2004.  On the other hand, if you are trying to grow something outside right now, you are, I am sure, having difficulties.  Many plants in my yard are showing frost injury, the “cool tolerant” plants are just sitting there in a state of shock.  If you are trying to germinate seed, I hope you are doing it in flats indoors because very few seeds will germinate in cold soils.


This is the time of year when you should be pruning fruit trees, roses, and any other plants that require some severe pruning.  Now is also the time to apply dormant sprays to trees and shrubs.  The dormant spray should consist of dormant oil for insect control, and a copper fungicide or calcium polysulfide for disease control.  If you have peaches or nectarines, the copper or calcium polysulfide is especially important to prevent leaf curl disease.  Use these fungicides and the oil according to label directions and apply them to thoroughly wet all the twigs, branches and trunk of the plant.  If your plants have scale infestations, the winter dormant oil spray is especially important.  However, if you are going to spray evergreen plants for insect control, do not use dormant oil, use instead a narrow range “horticultural oil,” also called a “summer oil.”  Horticultural oils are much less likely to cause phytotoxicity to plants with foliage present.


If you plan to top dress your permanent flower beds with manure or compost, the end of January and February is a good time.  The spring rains can then wash some of the nutrients into the surface layers of soil where new spring plant roots can absorb the nutrients for spring growth.


Finally, if you have plants that are showing frost injury, do not prune them now.  Wait until spring when new growth begins.  Then you will be able to trim the frozen wood back to living tissue and not destroy any more of your injured tree or shrub than necessary.

University of California Cooperative Extension Master Gardener Volunteers can provide additional gardening information upon request .Call the San Luis Obispo office at 781-5939 on Mondays and Thursdays from 1 to 5 PM.  You may also call the Paso Robles office at 237-3100 on Wednesdays from 9 AM to 12 PM.  The San Luis Obispo Master Gardeners website is at http://groups.ucanr.org/slomg/.  Questions can be e-mailed to: mgsanluisobispo@ucdavis.edu.