Q. We have a water shortage in our area. How much water do my plants really need to survive?
Pat M., Cambria
A. Water is essential for plant processes such as photosynthesis, nutrient uptake and transpiration, all of which directly affect a plant’s growth and development. During drought conditions when soil moisture is lacking, a plant’s growth and development are negatively affected.
Most garden plants need supplemental water when the rains have not sufficiently supplied adequate soil moisture. This is where you, the gardener, come in. Here are a few tips to keep your plants alive during a drought:
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▪ An individual garden plant needs about 1 inch of water each week. Then, delve deeper into various watering guides to determine how much water your larger plants and trees need. Wouldn’t it be wonderful if we could count on rainfall to provide it? But, alas, as custodians of our gardens we must provide for their minimal needs.
▪ Water only when the soil is dry. Use your hands or a trowel to check for moisture. When soil looks or feels dry 2-3 inches down, it’s time to water shallow-rooted annuals. However, if you’re caring for larger perennial plants or trees, dig deeper to evaluate the available soil moisture as these plants are deeper rooted than flowering annuals.
▪ Different plants have different water requirements. Shallow-rooted annuals, perennials, vegetables and newly planted landscapes will have different watering needs than larger, more established plantings. Trees and shrubs that are suited to our climate may need only occasional deep watering. The type of soil you have will dictate how often to water. For example, sandy soil dries out more quickly than clay.
▪ Water in the morning to give plants a chance to dry before dark. You’ll lose less moisture to evaporation and discourage fungal diseases.
▪ Be sure to follow any local ordinances or recommendations for landscape water use.
For more information on water-wise gardening, visit the University of California Garden Web — http://cagardenweb.ucanr.edu/Drought_/ — or the landscape watering guide for San Luis Obispo County at http://www.slowaterwiselandscaping.com/Watering-Guide/
Lee Oliphant is a UCCE Master Gardener.
Got a gardening question?
In San Luis Obispo call 781-5939, Arroyo Grande, 473-7190 and Templeton, 434-4105. Visit us at http://ucanr.org/sites/mgslo/ or email us at email@example.com. Follow us on Instagram at slo_mgs and like us on Facebook. Informative garden workshops are held the third Saturday of every month, 10 a.m. to noon at 2156 Sierra Way, San Luis Obispo. Garden docents are available after the workshop until 1 p.m. To request a tour of the garden, call 781-5939.