HOW CALICHE FORMS Wondering where that layer of caliche comes from?
First, calcium combines with carbon dioxide dissolved in the soil’s water to form insoluble calcium carbonate. Over time, soil particles become cemented together by calcium carbonate to create solid deposits known as caliche. Your digging may unearth random chunks of caliche mixed in with soil and rocks or concrete-like layers of caliche several inches to several feet thick. WHY CALICHE IS BAD Caliche creates several problems for gardeners. First, roots cannot penetrate through it. Shallow root systems are susceptible to drought stress as well as uprooting during windstorms. In addition, plants must survive on the limited nutrients found in the soil above the caliche layer. Second, water cannot soak through a tight caliche layer. This results in poorly drained, wet soil, which doesn’t provide the aeration that roots require. Think of a root ball in a planting hole set above caliche in the same way that a plant sits in a container without drainage holes. When water is unable to penetrat
