Horticulture Glosary
Ecosystem- a biological community of interacting organisms and their physical environment
Semi-natural Vegetation- vegetation that has been partly created or altered by human activity but still retains many natural features
Nomenclature- deals with the naming of plants
Taxonomy - deals with the principles on which a classification is based
Systematics - identifies the groups to be used in classification
Ephemeral - A plant that has several life cycles in a growing season and can increase in numbers rapidly
Annual- A plant that completes its life cycle within a growing season
Biennial - A plant with a life cycle that spans two growing seasons
Perennial- A plant living through several growing seasons
Tender- A plant that is damaged by low temperatures and must be protected from frost
Half-hardy - A plant that will tolerate low temperatures but must be protected from frost
Hardy- A plant that can survive the winter outdoors
Herbaceous - A plant with no permanent woody stem above ground
Woody - A plant with a permanent woody stem above ground
Evergreen - A plant that retains its leaves throughout the year
Semi-evergreen- A plant that retains some of its leaves during the winter
Deciduous - A plant that sheds its leaves in the autumn or winter
Humidity- the amount of water vapor in the air
Anemometer - an instrument for measuring wind speed
Tissue - a collection of specialized cells carrying out a particular function
Protoplasm - all of the living matter of a cell, nucleus and cytoplasm
Viable Seed- a seed that has the potential for germination given the required external conditions
Imbibition - the process of a seed absorbing water like a sponge taking up water
Osmosis - the process of cells taking up water, often doubling the size of a dry seed
Plant Development- processes that cause the changes in the plant during its life cycle
Epigeal - seed germination where the cotyledons are raised above ground
Hypogeal- seed germination where the cotyledons remain below ground
Dormancy- a period of time where the plant is inactive
Viability - ability to live or grow
Phototropism- the orientation of a plant or other organism in response to light, either toward the source of light ( positive phototropism ) or away from it ( negative phototropism )
Photoperiodism - the physiological reaction of organisms to the length of day or night
Weed- a plant growing in the wrong place at the wrong time
Pest- an animal that is harmful to plants or crops
Disease- a condition that impairs normal physiological function in a plant
Pesticide- used to cover all crop protection chemicals, which include herbicides (for weeds), insecticides (for insects), acaricides (for mites), nematicides (for nematodes), and fungicides (for fungi)
Topsoil - the uppermost layer of soil normally moved during cultivation. Typically it is 10 to 40 cm deep and darkened by the decomposed organic matter it contains
Subsoil- the layer below that normally cultivated and lighter in color because of its low organic matter level
Soil Texture - the relative proportions of the sand, silt and clay particles in the soil
Colloids- particles that are less than 0.001 mm in diameter and are kept permanently in suspension by the bombardment of vibrating water molecules
Soil Structure - the arrangement of particles in the soil
Infiltration - the process of water soaking into the soil
Surface Run-off- water that flows over the surface of the soil
Ponding - accumulation of water on the soil surface
Field Capacity (FC) - the amount of water remaining in a soil after free drainage has occurred
Available Water - the water held in the soil between field capacity and permanent wilting point and is available to plants
Soil Moisture Deficit (SMD) - the amount of water needed to restore a soil to field capacity
Fertilizers- concentrated sources of plant nutrients that are added to growing media
Major Nutrients- essential minerals required in relatively large quantities
Micronutrients- essential minerals needed in relatively small quantities, usually measured in parts per million