Successful gardening begins with a good plan. Choosing the right plants for the climate and soil conditions makes the difference in enjoyable successful gardening and a frustrating struggle to get plants to grow. While we cannot change our climate, there is much we can do to change our soil if we are willing to work at it. You should begin your plan by evaluating your soil type. Soil is made up of four parts: the mineral fraction, the organic fraction, water and dissolved minerals and air. The texture of the soil relates to the amount of sand, silt and clay the soil contains. The mineral fraction is composed of three types of particles; sand, silt and clay. Coarse sand grains are large enough to see and feel. Fine sand grains are less obvious unless they occupy 10% or more of the soil. You can’t detect slit grains by feel but they make the soil feel smooth and soapy but only slightly sticky. Clay, on the other hand, is very sticky when wet. A simple field test to help classify soil is to rub moist soil between your thumb and fingers.The particle size contributes a great deal to the soil properties. Particle size and arrangement affect all water percolation, water retention, aeration, how nutrients are supplied and release, and resistance to temperature changes or chemical charges. The texture of the soil relates to the amount of sand, silt and clay the soil contains. In general, loamy soils have the most desirable properties because they area blend of different soil textures. They have good moisture content and retain nutrients well as well as being very workable.

Clay soils and Clay Loamy Soils
Generally speaking clay and clay loamy soils retain water and nutrients more but don’t drain well. Adding organic matter reduces the stickiness of the clay. Clay also maintains soil temperatures better. Wet clay can be rubbed into a smooth unbroken smear. Clay loam’s particles cling together resulting in a grittier smear.

Sandy Soil and Sandy Loam
Sandy soils have excellent drainage but need more water and nutrients. Additionally, sandy soils need more protection from heat and cold. Adding organic matter reduces the graininess of sandy soils while increasing the soil nutrients. In your simple field test, moist sand particles will not hold together and feel hard and gritty. Loamy sand particles stick together but still have a gritty feel.

Silt Soil and Silty Loams Silt particles are in the middle of size between fine sand and clay. Silty loam soils make a rough broken smear when squeezed between the thumb and fingers.Besides soil texture other important factors figure into making your soil the best it can be. The pH of the soil and the fertility should be examined as well. We know that most plants do best when the soil pH is between 6.1 and 7.5. The lower the number the more acidic and the higher the number the more alkaline. Here on the west coast, with our heavy rainfall amounts, our soils tend to be more acidic as rains leach out much of the naturally occurring alkaline chemical elements. If this is the case a gardener can choose to grow more acid-loving plants like camellias, azaleas or hydrangeas which require a soil pH of about 4.5 to 5.5. The other choice a home gardener might make is to add lime to the soil to raise the pH level. Gardeners should also check the fertility of their soil in preparing a gardening plan. Determining the levels of nitrogen, phosphorus and potassium will help you decide on your type of soil amendments as well as being necessary to maintain the health of your plants. Soil fertility testing and pH tests can be performed with home test kits or by sending a sample off to a soil lab. In gathering your soil sample for either test, you need to collect soil from the root depth by digging a small hole at several sites within the area to be tested. Mix the soil samples together and follow the instructions on your test kit or bag your soil and send it off to the lab. Although home test kits are more cost-effective, outside labs give you much more detailed information about your soil. Soil structure should also be considered when choosing a soil amendment. Soil structure in its simplest definition is the size, shape and arrangement of the particles and aggregates and the size, shape and arrangement of the spaces between and the way they combine or clump together. Aggregation is the way the “peds” or soil crumbs or clumps cling together in a mostly permanent way. The shape of the particles defines how the particles fit together, much like pieces in a puzzle. While it is difficult if not impossible to change the soil texture, changing the soil structure is within our means. The introduction of organic soil amendments into the soil has a marked effect on soil and thus, plant growth and health. Soil amendments are materials that are incorporated into the soil by tiller or shovel to improve the structure. Organic amendments or “natural” amendments are derived from plant material so they naturally decompose. Mineral amendments like coarse sand or fine lava rock will improve drainage and aeration but will do little to change the soil fertility or structure. One of the important ways that organic material improves soil structure is that as it decomposes, the soil microorganisms that feed on the organic material secrete a sticky substance that is an important factor in “ped” formation. Soil microorganisms also release nitrogen into the soil from the breakdown of organic materials. The nitrogen that is release feeds the plants. Organic particles also help prevent platy soils from concreting together when they get wet. The wet organic particles retain moisture for the soil. When making your decision about soil amendments there are other factors to consider. To most home gardeners availability and price will be big considerations. Another thing to consider is how long a material lasts in the soil; if it decomposes rapidly will you be replacing it every season? Some “raw” products actually use nitrogen to break down, there by robbing plants of nitrogen. Using a “nitrogen-stabilized” product provides immediately available nutrients for your plants without the need to pull nitrogen from them to begin the decomposion process. Products like redwood sawdust are long lasting, taking as long as 10 years to completely decompose in the soil. Amendments using fir barks are considered more nutrient-rich and contain higher mineral levels. Lastly, consider what you are planting. Is you amending soil for containers or for large plants? Some larger sized plants like more aeration so larger sized amendments work better. Some people prefer a coarser amendment for heavier more compacted soils. Amendments that use sawdust are of a finer texture, and usually work better where seedlings and smaller plants are grown and amendments containing shavings are generally coarser and provider better aeration.