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 MATTER

SOIL 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 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 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 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 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 MATERIALS 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 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 MIXTURES Extra consistency Easy to use and cost less 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