\u00a0\u00a0\u00a0 Before we think about planting, it is a good idea to consider what kind of soil we are planting in. <\/span><\/span><\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0 Most of our soils in the Pacific Northwest arise from the interplay between volcanoes & glaciers.\u00a0 Volcanoes bring magma up from underneath the earth\u2019s surface.\u00a0 The magma becomes lava as it erupts from a volcano and then cools to become igneous rocks.\u00a0\u00a0 Glaciers erode the rocks as they move down the mountain.\u00a0 These massive rivers of ice grind rocks into smaller and smaller pieces.<\/span><\/span><\/span><\/p>\n

\u00a0\u00a0\u00a0 The Puget Sound was created from the action of glaciers advancing and retreating over many Ice Ages.\u00a0 Just 20,000 years ago, the Puget Sound was covered in a mile-high sheet of glacial ice.<\/a><\/span><\/span><\/span><\/p>\n

\u00a0\u00a0\u00a0 The type of soil you have in your yard will influence your success in growing different plant species.\u00a0 The figure above shows the USDA classification system for soil particles.\u00a0 For growing plants, we are mainly interested in the portions that are sand, silt or clay.\u00a0 Sand, by itself drains quickly and is not able to retain many nutrients.\u00a0 Silt is intermediate in size between sand and clay.\u00a0 Clay, by itself, prevents water from draining, but clay particles are good at holding nutrients. <\/span><\/span><\/span><\/p>\n

\u00a0 \u00a0\u00a0Soils are also classified by the relative percentages of sand, silt and clay as indicated by the Soil Textural Class Triangle. Loam soils, the most ideal, have about 33% sand, a 25% clay and 42% silt.<\/span><\/span><\/span><\/p>\n

\u00a0\u00a0 \u00a0\u00a0You can \u201cguesstimate\u201d your soil class by doing a feel test.\u00a0 For the feel test you take a small amount of soil and squeeze it in your hand.\u00a0 When you open your hand, you look to see how well the soil holds together.\u00a0 If it holds together, try to pinch the cast between your forefinger and thumb to a make a flattened ribbon to determine the amount of clay.\u00a0 If your soil has too much sand or clay, you may want to consider incorporating appropriate constituents to improve its structure.<\/span><\/span><\/span><\/p>\n

\u00a0 \u00a0\u00a0\u00a0The pore space between the particles is important for drainage and for gas exchange. Sometimes soils become compacted due to heavy traffic either by foot or by machines.\u00a0 Rototilling helps to loosen, aerate and mix soil but only to the depth of the rototiller. (It also helps to make removing weeds easier.) Some gardeners shun rototilling and depend upon natural systems to keep their soil pliable.<\/span><\/span><\/span><\/p>\n

\u00a0\u00a0 \u00a0\u00a0\u00a0Composted organic matter is also an important component of soils.\u00a0 It is any material derived from a living organism.\u00a0 It adds nutrients, increases nutrient-holding capacity, moisture retention and encourages microbial activity.\u00a0 A soil high in organic matter usually has a dark, rich color.\u00a0 Organic matter may be added to soils as green manures (cover crops) that are plowed in prior to planting, or by incorporating animal manures or compost.\u00a0 Many soil mixes used in horticulture, especially potting mixes, are \u201csoil-less.\u201d\u00a0 They may contain compost, peat moss, bark, perlite, pumice and\/or vermiculite. \u00a0\u00a0A \u201cgreen\u201d alternative to peat (which is mined out of ancient bogs) is coconut fiber (coir).\u00a0 <\/span><\/span><\/span><\/p>\n

\u00a0\u00a0 Another important factor affecting plant growth that people often overlook is soil pH; pH is the relative acidity or alkalinity.\u00a0 It affects what nutrients are available for uptake by plants.\u00a0 Most plants prefer a slightly acid soil (pH 5.5-7.0).\u00a0 On a scale from 0 to 14, Seven is neutral, the pH of distilled water; less than 7 is acid; greater than 7 is alkaline.)\u00a0 It is a good idea to test your soil, especially for pH.\u00a0 Test kits list recommended pH ranges for various crops and will tell you how to calculate the amount of amendments, such as lime, that should be added to your bed.<\/span><\/span><\/span><\/p>\n

\u00a0\u00a0 The microfauna, (bacteria, algae, fungi, insects, and worms) of soil also is important.\u00a0 \u00a0Charles Darwin studied and wrote a book about worms, \u201cThe formation of vegetable mould, through the action of worms<\/em>.\u201d The book is about the important role that worms play in decomposing and translocating organic matter in the soil and aerating the soil.\u00a0 He writes: \u201cI was thus led to conclude that all the vegetable mould over the whole country has passed many times through, and will again pass many times through, the intestinal canals of worms. Hence the term “animal mould” would be in some respects more appropriate than that commonly used of “vegetable mould.” <\/i><\/span><\/span>\u00a0Many bacteria, fungi and insects are also \u201cdecomposers.\u201d\u00a0 Some bacteria help plants by \u201cfixing\u201d nitrogen; absorbing it from the air and making it available to plants.\u00a0 Some fungi, such as mycorrhizae assist plants with nutrient and water uptake.\u00a0 Algae play a role in dissolving minerals.<\/span> <\/span><\/p>\n

\u00a0\u00a0\u00a0 <\/b>Epiphytes, plants that grow in trees do not need soil\u2013they are able to absorb water and nutrients directly from the air.\u00a0 <\/b>Most plants that we grow, however, are terrestrial plants, plants that grow in soil.\u00a0 (I have never been very interested in \u201chigh-tech\u201d horticulture such as hydroponics\u2014such systems are expensive, involve mixing a concoction of water soluble chemicals and are unnecessary as long as there is space to grow plants naturally in soil). <\/span><\/span><\/span><\/p>\n

\u00a0\u00a0 The plants and trees also affect the fertility of the soil as layers of organic matter are deposited and decomposed by the action of microorganisms.<\/b><\/span><\/span><\/span><\/p>\n

Feature Photograph: Mt. St. Helens<\/em><\/p>\n

\u00a0<\/b><\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0\u00a0\u00a0 Before we think about planting, it is a good idea to consider what kind of soil we are planting in. \u00a0\u00a0\u00a0\u00a0 Most of our soils in the Pacific Northwest arise from the interplay between volcanoes & glaciers.\u00a0 Volcanoes bring magma up from underneath the earth\u2019s surface.\u00a0 The magma becomes lava as it erupts from<\/p>\n","protected":false},"author":1,"featured_media":185,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"_links":{"self":[{"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/posts\/183"}],"collection":[{"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/comments?post=183"}],"version-history":[{"count":5,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/posts\/183\/revisions"}],"predecessor-version":[{"id":608,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/posts\/183\/revisions\/608"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/media\/185"}],"wp:attachment":[{"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/media?parent=183"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/categories?post=183"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/habitathorticulturepnw.com\/wp-json\/wp\/v2\/tags?post=183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}