In our desert climate, temperatures range from 2°C to 50°C (in the sun) during the hot season. Over the past 20 years, we’ve only experienced sub-zero temperatures once. Unlike the Mediterranean climate of coastal San Diego, our inland desert presents unique challenges due to extreme heat. Adapting to this climate, distinct from the milder coastal areas, requires careful planning.
Watering and Plant Selection
All trees and plants need water until they are established, especially the subtropical varieties I grow, which thrive with consistent moisture. We use a combination of drip irrigation and sprinklers to water them efficiently. Selecting appropriate plants is critical in this environment. While desert plants like prickly pear and rock roses require minimal water—cacti produce surprising amounts of food, and rock roses rely solely on cold-season rainfall—most plants need regular irrigation.
Creating Microclimates
Unlike northern gardeners who create warm microclimates, we focus on cooling strategies. My food forest emphasizes a dense canopy to reduce evaporation, increase humidity, and lower temperatures. Tall trees with broad canopies provide shade, while mid- and low-level trees add density. For example:
• Raspberries grow in a shaded corner under avocado, palm, hedge, and prickly pear.
• Additional raspberries, blackberries, and alpine strawberries thrive beneath plum trees.
• Currants and gooseberries are planted under a pecan tree for shade.
Tree collards, a low-water vegetable, work well once mature, though they need irrigation during establishment. Berry plants also require regular watering, but drip irrigation keeps our household water bill between $75 and $100 monthly.
Soil and Temperature Management
To protect roots from extreme heat and occasional cold, I use compost and straw mulch, which also reduces evaporation. On rare nights when temperatures drop to 4°C, followed by 40°C days, I’ve lost trees and fruit to these swings. To mitigate this:
• Thick mulch insulates roots.
• Young trees are coated with white clay or wrapped in burlap to prevent sunburn or cold damage.
• Bananas, which are cold-sensitive, have their flowers and fruit covered with burlap when temperatures dip below 5°C to prevent frost damage and ensure fruit production.
Raised Beds and Herbs
Shade cloths are essential for my raised herb beds, where I grow over 30 varieties of herbs and spices. Without shade, many would perish in the intense heat. In the food forest, the ground layer dies back during the hot season but thrives otherwise. I grow long-rooted vegetables like daikon radishes, turnips, beets, and rutabagas, as well as brassicas (kale, collards, broccoli), leafy greens (mustard, lettuce), herbs, and edible flowers. Pigeon peas, planted this year, have adapted well to our climate. Black tea, black pepper, long pepper, and coffee plants grow under shade covers until the canopy trees mature.
Chaos Gardening and Seed Starting
I practice chaos gardening by scattering a mix of expired seeds, free seeds, wildflowers, and herbs from a mason jar across the forest floor in February, when rain is forecast. A thin layer of compost protects the seeds from birds. From February to August, sprinklers supplement rainfall, and by April, a vibrant mix of flowers and vegetables emerges, supporting the ecosystem and deterring wild rabbits from eating my blueberries.
Most plants are not direct-seeded due to the heat. Instead, I start seedlings in an indoor nursery (a repurposed large shower). This allows me to:
• Germinate cold-season crops that struggle in high temperatures.
• Manage overlapping harvesting and seeding schedules.
• Transplant strong, mature plants by late October, yielding lettuce and brassicas for Thanksgiving and Christmas.
This year, I started seeding two weeks late due to a cold virus, but the process remains effective.
Future Plans
In Denmark, we relied on rainwater collection, and we plan to implement it here when time allows. This will further reduce our water usage and support sustainable gardening in our desert environment.
Final Thoughts
Your climate, with its winter season, likely requires different strategies. In Denmark, we used cold frames and greenhouses to grow fresh greens year-round. Here, shade, mulch, and careful irrigation are key to thriving in the desert. I hope this insight helps you adapt to your own gardening.
Happy Gardening