Experts tackle readers’ garden questions.
Q: Wife and I are arguing about proper way to water our plants. We have a small orchard, garden and extensive landscaping with palms and sagos. When I water late in evening or early morning, I spray the whole plant. Wife says to only direct water to base or ground and not water branches or leaves. Which is better? I’m especially concerned about our sago palms as we have several of them, both in pots and in the ground. Neither of us thinks it’s good to spray whole plant when direct sun is hitting the plant.
Steven Parks, Granite Bay
Sacramento County Master Gardener Carmen Schindler: Your wife gets the kudos for being correct. Ideally, plants should be watered in the soil using a drip irrigation system around their drip lines (the outer circumference of the tree or shrub canopy). If using a spray system, adjust sprinklers or install deflectors to prevent the trunks from getting wet.
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Follow these best tips for all plants, including trees:
▪ Apply water to the soil around the base of a plant, avoiding the trunk or branches.
▪ Mulch, mulch, mulch! A layer of three to four inches of mulch will reduce water evaporation and weeds, and protect roots from heat.
▪ Water infrequently and deeply to encourage deeper root growth, which results in plants with greater drought tolerance.
▪ Use a drip irrigation system, grouping plants with similar water needs together on one valve.
▪ Occasional spraying of foliage to remove dust or an insect infestation is beneficial.
The California Center for Urban Horticulture (CCUH) at the University of California, Davis, UC Division of Agriculture and Natural Resources (ANR) and Ewing Irrigation have devised a unique watering system called the Tree Ring Irrigation Contraption (TRIC). TRIC is a kit that homeowners can put together themselves for about $100 for one large tree. For more information, visit the CCUH website at ccuh.ucdavis.edu.
In addition, too much or too little water can damage landscape plants. Inadequate water causes foliage to wilt, discolor and drop. Prolonged moisture and poor drainage can result in smaller leaves, dieback or limb drop, and susceptibility to root rots, mineral deficiencies or toxicities, wood-boring insects and other pests that eventually can kill plants. Excessive moisture smothers and kills roots, leading to discolored and dying foliage.
Maintain adequate, but not excessive, water in the soil to ensure plant survival and good growth. Examine plants regularly for symptoms of water stress. Monitor soil moisture around each plant’s root zone and adjust irrigation according to seasonal needs. Soil around young plants during hot weather may need to be monitored daily; every few weeks may be adequate when monitoring around mature trees during more favorable weather.
Just before dawn or early morning is generally the best time to irrigate. Evaporation is lower during these hours and usually there is little or no wind to disrupt the pattern of the sprinklers. In addition, water pressure is more favorable during this period. Irrigating in the evening also can minimize evaporation, but avoid overhead sprinkling if foliar (leaf) diseases are a problem because leaves will remain wet longer than watering at dawn.
For additional tips on good irrigation practices, go to the UC ANR website at ucanr.edu. For information on watering the backyard orchard, visit the UC Master Gardener Program website at homeorchard.ucanr.edu.
Carmen Schindler is a UC Cooperative Extension Master Gardener for Sacramento County.
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to email@example.com. Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:
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