Glossary - Horticulture

Basic glossary of terms used on this website.

Term	Description
Bacteria	They are minute single-celled organisms and cannot be seen with the naked eye. Their size range between 0.0005-0.005mm. Bacteria are often referred to as germs and are found in the soil, water, air and on living organisms (even your hands, feet, lips, eyes and hair). They are found in their millions and can cause serious diseases. They also help with the decomposing process of dead plant material.
Beefsteak tomatoes	Standard large tomato. These tomatoes are not long life tomatoes. Size usually larger than 80 mm (3.14 inches)
Bulk	The format in which large amounts of produce is sold. Usually in crates or by bakkie load. Produce sold in smaller packaging such as punnets are not sold in bulk except if large amounts of punnets are sold.
Crop rotation	Crop rotation may be defined as the growing of two or more crops in regular sequence on the same land during a period of two seasons or two years.
Commercial seedling mix	A growth medium sold on a commercial scale developed specifically for seedlings for optimum growth and germination.
Demand	The quantity demanded of a product is the amount that will be purchased per time period under a given set of circumstances.
Drench	To drench is to thoroughly wet a surface with water or any liquid so that there are no dry areas and all the excess water has run off or leached.
EDDHA	Ethylenediaminedi-o-hydroxuphenylacetic acid. A fertilizer for ferric iron (Fe 3+ ) in chelated format. It is used when the pH of the medium is high, above 7.5.
EDTA	Ethylenediaminetetraacetic acid. A chelated fertilizer for ferric iron (Fe 3+ ), manganese, copper and zinc. It is used when the pH of the solution is below 7.
Expenditure	Expenditure is a cost that is incurred in order to obtain a service or a product.
Fertigate / fertigation	Fertigation is the combination of applying water soluble fertilizers through an irrigation system. These systems are usually drip irrigation systems.
Fixed costs	Fixed costs are those costs that can easily be identified each month and have the same amount such as ones policies, rent and bus card costs.
Fungi / fungus	These are plants, moulds, mushrooms and yeasts. They do not have chlorophyll and are either parasites or saprophytes. Many fungi cause diseases such as blight, mildew, rust etc. Some fungi (specifically the saprophytes) are important during the rotting process of plants and they help with the release of nutrients to the soil.
Germination percentage	The germination percentage is determined through a small test using 100 seeds and under controlled environment determining how many of the 100 seedlings have germinated. If only 50 germinated the seed has a germination percentage of 50%.
Growth medium	A medium specially prepared for either seedlings to germinate in or mature plants so as to improve growth and quality of the plant.
Income	Gross re-numeration of business activity
Inert	A material, such as a rock, that will not deteriorate and lose its structure and chemical composition.
Pathogens	An organism or substance which causes disease in plants. Pathogens can be soil born or be transmitted form dead plant material.
Polystyrene	A very light material made from small white foam balls. It is mostly used in the packaging industry to transport goods that can be broken easily.
Perlite	Mixture of a clay and polystyrene and is used as seedling growth medium
Propagation	The artificial multiplication of plants by various means.
Seedling environment	It is the small micro climate that affect the seedling and its growth.
Soil ridge	A raised strip of soil. Plants are planted on the highest point of the ridge in order to improve growth due to restricting conditions such as water logging, soil borne diseases etc.
Solarization	This is done by covering the seedbed with a transparent plastic sheet for three weeks. The heat of the sun increases the temperature of the soil, killing pathogenic micro-organisms, and weed seeds
Spindly seedlings	Seedlings that have either grown with to little light or are planted to densely and have been left for to long in the seedling trays or bed.
Sterilized medium	A growth medium that is free from harmful fungi and bacteria as well as any weeds.
Supply (in marketing)	Supply is the culmination of all on farm decisions taken within the farm firm that leads to the supply of agricultural products on to the various markets.
Transplant	A transplant is a seedling that has just been planted into the soil where it will stay to grow and mature.
Thinning out	The process of removing seedlings from the plugs in seed trays so that there is only one seedling per plug. Thinning out is also applied in a seedbed so as to ensure that the seedlings do not grow to close to each other resulting in spindly seedlings.
Utility	The satisfaction one obtains from purchasing or using a product
Water holding capacity	The amount of water that a medium will hold after all the excess water has leached out
Successive cropping	When two or more crops are grown in sequence on the same land in one year.
Common name	This is name that the people of the area or country use to identify the crop.
Scientific name	This is the name that is used internationally to identify a crop
Micro sprinklers	Micro sprinklers are devices that spread small amounts of water over a wide area in order to reduce the risk of soil erosion and to prevent any damage to small plants. However they are not effective where there is a lot of wind.
Virus	These are sub-microscopic, self reproducing protein agents which infect plants and animals causing disease. A classic example is a virus called TMV or “Tobacco Mosaic Virus”. The virus is found in tobacco that we smoke and is transferred to tomato plants when handling the plants and smoking at the same time. TMV can cause serious losses in a tomato crop.
Crop season	That is the length it takes for any crop from germination until it perishes under natural conditions. It is usually less than a year. Some crop may survive more than a year such as asparagus, but the season in which they grow and in which they are harvested is less than a year long.
Seedling	A seedling is a very young plant not older than 6 weeks and has not been transplanted into its permanent position in the field.
Peat	An organic soil consisting of plant material accumulated in anaerobic waterlogged conditions in which bacteria and earthworms are absent and decay is very slow. Peat is imported from England or Canada.
Compost	The manure derived from decomposed plant remains.
Kraal manure	The manure derived from decomposed non-digested and digested animal remains. It does not include parts of the animal itself.
Pot soil or potting soil	Potting soil is never used in the vegetable industry. It is used for home gardens where plants are grown in small pots. It includes compost and soil. Potting soil is not sterilized.
Data	Data are a group of non-random symbols which represent quantities, actions, things etc.
Information	Information is data that have been processed into a from the is meaningful to the recipient and is of real or perceived value in current or prospective decisions
Convection	The transfer of heat or energy from one place to another through air or water.
Conduction	The flow of energy (heat) from a point of higher temperature to that of a lower temperature.
Radiation	All bodies radiate heat energy from their surface.
Condensation	Condensation is the process of changing vapour into liquid. It requires the extraction of heat from the vapour. Typical example is the greenhouse effect found in the mornings on the inside of the greenhouse cladding material.
C factor	The “C” factor is found in literature using British Thermal Units to express heating requirements for greenhouses. The “C” factor is the conductance between two surfaces and is measured in BTU h -1 ft -2 °F -1 .
K factor	The “K” factor is found in literature using British Thermal Units to express heating requirements for greenhouses. The “K” factor is the thermal conductivity coefficient and is measured in BTU h -1 ft -2 °F -1 .
U factor	The “U” factor is found in literature using British Thermal Units to express heating requirements for greenhouses. The “U” factor is the overall heat transfer coefficient and is measured in BTU h -1 ft -2 °F -1 .
Infiltration	In ventilation: referred to the air movement through small openings and cracks in the greenhouse structure and cladding material. Infiltration can contribute significantly to heat loss during cold periods.
Adaxial surfaces	The flat internal surface of cotyledons
Antennae	The first pair of insect appendages. These are sensory and are usually jointed.
Coalesce	Usually referring to infected leaf with bacteria and the infected parts enlarge to form one larger infection