2. 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

3. 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

4. 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

5. 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

6. 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

7. SOIL PARTICLES Particles are classed according to size
Coarse (largest particle size)
Sand and gravel
Medium
Silt
Fine (smallest particle size)
Clay

8. 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

9. ORGANIC MATTER

10. SOIL TEXTURE TRIANGLE

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

18. 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

19. 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