This is the second article of a series on Sustainable Landscape Design in San Diego.
Sustainable landscape design is a multi-headed concept. In the San Diego area and throughout California, the definition of sustainable landscaping – filling garden beds with plants that can be harvested and eaten -- broadens into creating a backyard (or front yard) habitat that is also environmentally sensitive. What does this broader definition really mean? Sustainable landscaping in California, considered the driest of all Mediterranean climates in the world, translates to producing edibles, while at the same time conserving water. These two goals can conflict with each other. It’s a tricky set of tasks, especially in drought years, to produce bounties for the table with plants that require regular irrigation cycles, while adhering to water restrictions. So how do we actually grow food for our table and, at the same time, proscribe to the water-wise ethic? Here are some basics.
Soil: Condition soils to absorb and retain water until roots can utilize it. California’s urban areas typically lack organic materials that must be initially brought into the site. Fully amend the soil with organic material (soil amendments) and organic fertilizers. Then set up on-site composting bins to continue the process.
Mulch: Organic mulch materials – top dresses -- must be laid as a top layer to prevent water from evaporating. As a bonus, a layer of organic mulch will reduce weeds that will be robbing water that is intended to go to desired plants.
Irrigation: Most of the irrigation in San Diego is automatic, set a clock and forget about it. In the era of so called “smart” controllers, computers do the work for us. But the hands-on approach to watering can help save water as well. Try hand-watering the old fashion way in cultivated rows and basins. Water deeply when you irrigate, check the soil moisture regularly.
Water Requirements: Install planter beds with plants that have the same basic water requirements. This should go without saying but sometimes gets overlooked, not only in the edible garden but in all types of landscape. Know your plants – plan garden beds with plants that thrive on the same water cycle.
Plants: There are those that need abundant moisture and there are those plants that survive, even thrive on less. Without sacrificing at the table, minimize those plots that need lots of irrigation, then look into those harvestable plants that grow well with less. For instance, a Bay Tree (Laurus nobilis) grows directly out my window as I write this, which I use for seasonings. It grows well without much, if any supplemental irrigation, yet would gladly drink from garden beds receiving regular irrigation if improperly placed. Select plants that grow in the same microclimate areas, factoring in soil, sun-shade, and water.
These are just a few basics to getting started. There is a lot to think about when designing the sustainable garden. I will be discussing more on the subject in future posts – Steve Harbour.