Question: Most of our garden books always recommend planting in a “loamy” soil. What exactly is loam?

Answer: Soil is composed of many particles of varying sizes. Soil scientists have classified soil particles into three major groups: Sand, silt and clay. Sand particles are the largest and tend to hold little water but allow good aeration. Clay particles are very small in size and tend to pack down so that water does not drain well and little or no air can penetrate. Silt particles are medium sized and have properties in between those of sand and clay.

A loamy soil then, is one that combines all three of these types of particles in relatively equal amounts. Loamy soil is ideal for most garden plants because it holds plenty of moisture but also drains well so that sufficient air can reach the roots.

Many gardeners complain of their garden soil being compacted and or poorly drained. Heavy, compacted soil can be rescued by the dedicated gardener. Annual applications of organic matter, such as compost, animal manure, cover crops or organic mulch materials will help to improve overall soil texture. It may take several years, but eventually the soil compaction will be improved. Although adding some sand along with the organic matter is acceptable, adding sand alone is not advised. The organic matter offers several advantages that sand does not, including increased water and nutrient holding capabilities, in addition to improved aeration.

Highly sand soils can be a problem since they do not hold much water and few nutrients, as well. Adding organic materials to a sandy soil will improve its ability to hold water and nutrients. You’ll need to add at least a two-inch layer of material to make a marked improvement. This translates to about 17 cubic feet of organic matter to cover a 100 square foot area.

Remember that soil improvement is a program, not just a one shot deal. You’ll need to continue applications at least once a year for several years to really change the nature of the existing soil.

Question: Most of the garden articles I read refer to the pH requirements of the plant. What exactly does this term mean?

Answer: A pH is a reading taken from a scale that measures the chemical reaction of the soil. Simply put, the reading expresses the degree of acidity or alkalinity in terms of pH values, very much like heat and cold are expressed in degrees centigrade or fahrenheit on a thermometer. The major effect of pH on plant growth is its effect on the availability of plant nutrients and soil concentration of plant-toxic minerals. In highly acid soils, aluminum and manganese can concentrate and be toxic to plants. In highly alkaline soils, where pH is 8.5 or above, high sodium content can cause problems by inducing deficiencies of calcium or manganese.

When the pH drops below 6 (becomes more acidic), phosphorus, calcium and magnesium can become needed nutrients. When pH approaches 8 or above, iron and magnesium rapidly tend to become unavailable. The pH of a soil can be adjusted by adding specific materials. To make soils less acid, apply lime. If the pH of the soil is too high, add elemental sulfur.

Our Western Washington soils tend to be acidic and that is a real benefit for us since the majority of home garden plants grow best in moderately acid soil. Soils with a pH from 5.5 to 7.0 do not need soil amendments to adjust the pH level. An easy way for home gardeners to see just how much of an impact pH can have on plants is by doing some experimenting with their hydrangeas. Although they are usually pink or blue, their color can be intensified or changed by changing the acidity of the soil. Lime on the soil makes the flowers pink; alum makes them blue; super phosphate deepens the pink almost to red. A hydrangea in the garden may be half blue and half pink where soil on one half is acid and the other half alkaline.

To change blossom colors this year, the appropriate applications need to be made now.

Question: We almost always refer to plants in our garden by their common names. Why do some people insist on using Latin names? They are hard enough to just pronounce let alone remember.

Answer: Although it’s not something a gardener is usually eager to do, it’s a good idea to become familiar with and learn the Latin (botanical) names of plants. Referring to plants by their genus and species assures that gardeners are communicating about the same plant rather than relying on common names which are not standardized and can be confusing.

Each Latin botanical name is actually a fascinating puzzle that can tell you a great deal about the plant and how it is identified. The genus name is always a noun; mentha – it is a mint. The species name is commonly an adjective describing the genus name; piperata is like pepper (strong, pungent, spicy). So Mentha piperata is a peppery mint. The species name of a plant can tell you what color its flowers are (albus = white, coccineus = scarlet), what it smells like (foetida = fetid or stinky), perfumatissima = like perfume), where it originates (chinensis = China, virginiana = Virginia), it’s natural habitat (aquatica = water, arvensis = field), or its form and habit (reptans = creeping, gracilis = graceful or slender).

Other species names are a little more complex, as in grandiflora; the prefix grandi means large, flora means flower. Other common prefixes include leuco (white), macro (long or large), semper (always), and brevi (short).

EDITOR’S NOTE: For answers to local gardening questions, contact Master Gardener Rachel Gana at 642-8723 or e-mail her at: baiter1@pacifier.com.