Extreme Weather and Gardening in the Age of Climate Change

It used to be that Californians never had to consider much beyond their own tastes when selecting plants for home gardens. But times are changing along with the climate, and the impact of backyard gardens is being considered on a scale never before questioned. Does the garden conserve water and enrich the soil? Does it offer habitat protection to living things? Could it store more carbon or produce more food? Do changes in frost dates affect food production?

The insights of recent scientific studies reveal how living things constantly influence each other and their surroundings. We now understand that the soil under our feet is teeming with life, that a routine application of fertilizer and insecticides has a significant impact on the environment, and that collateral damage on non-target species can no longer be ignored. It is also clear, now, that backyard gardens play a crucial role in preserving habitat corridors for threatened species of birds, bees, and butterflies.

Here is a list of quick suggestions for gardening in a time of climate change and habitat destruction to help make each garden part of the healing of the planet. Small changes add up to a lot.

Approach climate change through mitigation and adaptation. Cut down on gas-powered tools and fossil fuel-based fertilizers to slow climate change by reducing greenhouse gas emissions.

• Plant shade trees. Plant deciduous trees on the northeast-to-southeast and northwest-to-southwest sides of your house. They reduce air temperatures by 9-12 degrees, provide shade protection from summer sun, and offer warming winter sunlight. For information on firewise tree placement, refer to our web page, Wildfire Preparedness in the Home Landscape.
• Maintain woody plants. Protect plants that sequester carbon and reduce atmospheric CO₂ 

Conserve water in your landscape. Irrigate efficiently by replacing sprinklers with drip irrigation. Decrease irrigation as plants’ needs lessen along with day length in late summer. 

• Group plants with similar water needs and sun exposure. Take into account root depth, slope, and soil type. Water each hydrozone with a separate valve if you have an automated irrigation controller or from separate hose bibs.
• Rely on low-water-use plants. Choose Mediterranean plants and California natives, which use about one-quarter of the water that high-water-use plants need.
• Keep water on your property. Install permeable hardscape such as flagstones and decomposed granite that allow water to filter into the soil and recharge the underlying aquifer. Berms (mounds), swales (valleys), and raingardens spread rainwater, giving it time to percolate down. Consider harvesting rainwater with tanks or barrels.  “Slow it, spread it, sink it, store it.”  

Incorporate compost into your garden. Employ regenerative practices using compost that provides nutrient-rich food for soil microbes and plant roots. Organic matter improves soil health, creates and maintains good soil structure, retains water, and sequesters carbon.

• Plant cover crops.Plant cover crops for fall and winter growth to prevent erosion and runoff, keep carbon dioxide in the soil, maintain soil structure, and feed the soil. Prior to spring planting, turn leguminous and grass cover crops into the soil to add organic material.
• Cover soil with mulch. Spread organic mulch to prevent erosion, moderate soil temperatures, conserve moisture, and reduce weeds. As mulch decomposes, it becomes compost and feeds microorganisms in the soil. 
• Minimize fertilizer.Understand that nutrients remain in decomposed organic matter in the soil until they are needed by plants. Compost is all the food most soils need to support plants. Excess inorganic fertilizers are easily leached from the soil and end up polluting waterways.

Be part of a "growing community." Share food, seeds, plants, and garden information with your neighbors, farmers, and friends. Engage friends and neighbors in discussions about climate change using reliable sources for information. Track daily weather trends to observe climate changes over time. Become a citizen scientist by sharing data you collect with local or online organizations.

• Grow your own food. Grow nutritionally rich, pesticide-free, fresh food to decrease airborne CO₂  generated by food transportation over long distances. Home gardening increases your own and your community's local food security.
• Stay flexible and adaptable. Try new strategies for adapting to changing conditions by using shade cloths, frost covers, and hoop houses. Plant fruit and vegetable varieties suited to changed conditions, such as fewer frost days for fruit and nut trees.

Resources:  

• Cornell Garden-Based Learning, Gardening in a Warming World, 2018
• QWEL (Qualified Water Efficient Landscaper) Reference Manual, Sonoma-Marin Saving Water Partnership, 2018. 
• WUCOLS IV, A Guide to Estimating Irrigation Water Needs of Landscape Planting in California.  2000.
• State of California Department of Water Resources Water Efficient Landscaping
• UCCE Gardening After a Flood
• UC Master Gardener Program of Sonoma County No-Till Food Gardening
• UC Master Gardener Program of Sonoma County Gardening and Drought

July 2023