The coronavirus quarantine has sent many of us into our gardens for sanctuary, escape, enjoyment, and new beginnings as well as to grow food and feed your family. If you are a longtime gardener, this is a great time to prepare your garden for climate change. If you are brand new to gardening, get things started with climate change in mind.
What can we expect from climate change? You have probably heard climate scientists talk about warmer temperatures, but there is much more to climate change.
Rainfall overall may not change but the rainfall pattern will. Rainstorms will not be as frequent, so we will have longer dry periods in between. When the rains do arrive, they will be far more intense. We have already received hints of that. Do you remember the rains we had back in mid-April? My home weather station recorded more than 9 inches of rain in a week and 4.5 inches of rain on one day. That one day’s rainfall was more rain than in all of 2018!
How can you prepare your garden for heat, intense rainfall, and longer dry periods?
- Plant water-wise plants. They require little irrigation and have a better chance of surviving the long, hot, dry periods between winter rains. Our native plants, succulents, plants from other Mediterranean climate regions of the world, and plants from dry regions of Baja California, Mexico, are the best choices.
- Upgrade your garden’s irrigation to in-line drip. In those long, dry periods, ornamental plants will likely need watering. In-line drip irrigation (not point-source irrigation, which involves individual emitters at each plant) is the most efficient and effective irrigation and is very low maintenance. This kind of drip irrigation wets the entire root zone, so there is no need to add emitters over time. Run in-line drip irrigation for an hour or more each time, but not very often. Water-wise plants need the soil to dry out in between watering.
- Install a rainwater collection system. Every square foot of your roof collects 0.6 gallons of water per inch of rainfall. That translates to 1,200 gallons of water for a 2,000 square-foot roof during a 1-inch rainfall. Collect that water in a cistern or tote. Then use it to water your garden in dry periods.
- Create dips and swales to capture rainfall on your property. In the old days, the goal was to direct water off your property as soon as possible. Now, the goal is to keep as much water on site as possible. Create swales, dry streambeds, dips, and depressions in your landscape. In these places, water can collect, sit, and sink into the soil slowly over time, making it available to plant roots between rainstorms.
- Spread a 3- or 4-inch-thick layer of mulch. As wood-based mulches break down, they support the important soil microbes that move water and nutrients to the plants’ roots. Improved soil texture is a mulch byproduct, as is the soil’s ability to soak up and hold water like a sponge. A layer of wood-based mulch or rock mulch insulates the soil to hold in moisture between rainstorms or between watering. In a rainstorm, mulch also helps slow erosion by buffering the impact of raindrops hitting the soil. Just remember to leave some bare dirt somewhere in your garden (at least 5-by-5 inches) for bumblebees and other ground-dwelling native bees. They seldom sting and are very important pollinators.
- Plant trees. Climate change is largely the result of increased carbon dioxide in the atmosphere. Trees capture and store that carbon dioxide; their shade cools our homes while the water that trees release cools the atmosphere. Trees help stem soil erosion, filter particulates and pollutants from the air, and create the oxygen we breathe. The best time to plant a tree was yesterday. The second-best time is today. Let’s plant trees!