SOIL•Medium: The soil

mixture is the plant’s source for food, water, and support

▫The soil mix will have effect on the health, vitality, and appearance of a plant or crop

SOIL FORMATION•Begins as rock that is broken into

smaller particles

▫Snow, ice, wind, and rain

•Parent material: The original rocky material before weathering has taken place

• Lower plant forms such as lichens, moss, and fungi grow on rock matter

•Organic matter: The decay of plants and animals which is essential for soil formation

WEATHERING•Changes the consistency, chemical makeup,

moisture, content, and general composition of a soil▫Physical and chemical weathering

•Physical: Caused by heating and cooling, freezing and thawing, wind and water

•Chemical: Reaction and interaction of water, oxygen, carbon dioxide, and other substances

TOPOGRAPY• The surface features of a region

including hills, valleys, rivers, lakes, and mountains

•Causes particles to move up or down slopes and relocates the parent material

•Soil is ever changing because of:

▫Particle structures, sizes, types, amounts or organic and inorganic content, layers of soil, and pH values

SOIL COMPOSITION•Minerals: The

inorganic material in a soil▫Usually 64 elements

•Organic matter is comprised of decayed or decaying plants or animals

•Porous fraction of soil contains water and air▫Ideal ration is 50:50

SOIL PARTICLES•Particles are classed according to size•Coarse (largest particle size)▫Sand and gravel

•Medium▫Silt

•Fine (smallest particle size)▫Clay

SOIL TEXTURE•Refers to the size of

individual particles•Soil is a mixture of:▫Sand, silt, and clay

•The percentage of each particle determines the soil’s ability to drain and hold water

•Loam: Contains a percentage of sand, silt, clay, and organic matter

ORGANIC MATTERORGANIC MATTER

SOIL TEXTURE TRIANGLESOIL TEXTURE TRIANGLE

SOIL WATER•Leaching: Movement of

water and nutrients away from plant roots

•Capillary water: Held by the soil and available to plant through their roots

•Gravitational water: Moves down and away from the surface by gravity, not used by plant roots

•Hygroscopic water: Held so tightly by soil it is unavailable to plants

SOIL pHSOIL pH•pH value: The acidity or

alkalinity of a soil▫Plants have a preferred pH range▫pH scale = 0 – 14

Acidic: Below 7 Alkaline (basic): Above 7 Neutral: 7

•Soluble: Ability to dissolve•Microorganisms: Microscopic

plant or animal life that decompose organic matter in soil or media

PLANT MEDIUMPLANT MEDIUM•Requirements for a good plant medium:▫Moisture and nutrient retention▫Good porosity▫Provide support for the

plant▫Shrinking and swelling▫Must be sterilized in

greenhouses▫Has to be reproducible

•Porosity: The air space (pores) between solid particles of soil or medium

•Aeration: Movement of air through the soil

SOIL MEDIA MATERIALSSOIL MEDIA MATERIALS•Organic matter: Decomposing

remains of plants and animals▫Loosens texture and holds water

Compost: Dark soil of decomposed organic matter used as a fertilizer

Peat Moss: Partially decomposed plant matter that has high water retention

Sphagnum Moss: Dehydrated stems and leaves of acidic bog plants

Pine Bark: ¼ inch or smaller pieces of bark which absorbs nutrients and releases them slowly

NATURAL SOILSNATURAL SOILS•Topsoil is the uppermost

layer of soil and consists of:▫Air▫Water▫Minerals▫Organic Matter

•The heaviest media material used is MASONRY OR PLASTER SAND which has sharp, coarse particle

INORGANIC MEDIA INORGANIC MEDIA MATERIALSMATERIALS• Inorganic matter: Media which

contains no organic (plant or animal) particles▫Perlite: VOLCANIC rock crushed

and heated to 1800 degrees Fahrenheit Improves aeration and water holding

capacity▫Vermiculite: Mica compound

heated to 2000 degrees Fahrenheit Improves moisture retention

▫Wetting Agents: Chemicals which change the properties of water or other liquids

SOILLESS MIXTURESSOILLESS MIXTURES•Artificial soils are media mixtures where

soil has been replaced with other materials▫Developed because of the shortage of good

horticultural-grade soils▫Agricultural and roadside soils have been

treated and are harmful to plants Pesticides Construction materials Mineral salts

SOILLESS MIXTURESSOILLESS MIXTURES•Extra consistency▫Maintained from batch to batch

•Easy to use and cost less•Good drainage and aeration

•Hydroponics: Growing method which uses a mineral-nutrient water solution instead of soil▫Growing solution can be

easier than soil▫Can be expensive to set up and

maintain