Plant Science Terms - F
Fallow - a system in which land is left unplanted without a crop for one or more growing seasons to accumulate moisture and restore nutrients
Family - a sub-order in the classification of plants
Fasciation - distortion of a plant that results in thin, flattened, and sometimes curved shoots
Fastigiate - (of a tree or shrub) having the branches sloping upward more or less parallel to the main stem
Feeder roots - fine roots and root branches with a large absorbing area (root hairs.) Responsible for taking up the majority of a plant’s water and nutrients from the soil
Fertility (soil) - presence of minerals necessary for plant life
Fertilization - fusion of male and female germ cells following pollination; the addition of plant nutrients to the environment around a plant
Fertilizer - any substance added to the soil (or sprayed on plants) to supply those elements required in plant nutrition
Fertilizing - to add nutrition to your plants using either commercial or non commercial fertilizers or compost
Fertilizer analysis - minimum amount of nitrogen, phosphorus (as P2O5), and potassium (as K2O) in a fertilizer expressed as a percentage of total fertilizer weight as stated on the label. Nitrogen (N) is always listed first, phosphorus (P) second, and potassium (K) third. An example would be as 16-4-8
Fertilizer ratio - the smallest whole number relationship in relative proportion of N, P2O5, and K2O. The ratios of 16-4-8 and 8-2-4 are both 4:1:2, which means 4 parts nitrogen to 1 part phosphorus to 2 parts potassium
Fibrous root - a root system that branches in all directions, often directly from the plant’s crown, rather than branching in a hierarchical fashion from a central root. (See also Taproot.)
Field capacity - amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. This usually takes place 2–3 days after rain or irrigation in pervious soils of uniform structure and texture
Field signature - distribution pattern of the disease over all plants of the same species
Filament - stalk supporting a flower’s anthers
Filler - plants that fill in the middle area of a container connecting the spillers and fillers and making the container look full
Flag or Flagging - loss of turgor and drooping of plant parts, usually as a result of water stress. Can be seen as branch loss in a tree
Flecking or stippling - numerous very small chlorotic or necrotic points
Floating row covers - covers, usually of a cloth-like material, placed over growing plants and used to protect the plants growing beneath from undesirable pests and climate
Floricane - second-year growth of cane berries. Produces fruit on laterals
Floriculture - study of growing, marketing, and arranging flowers and foliage plants
Flower - a shoot of determinate (limited in number) growth with modified leaves that is supported by a short stem; the structure involved in the reproductive processes of plants that bear enclosed seeds in their fruits
Flower bud - a type of bud that produces one or more flowers
Foliar fertilization/feeding - fertilization of a plant by applying diluted soluble fertilizer, such as fish emulsion or kelp, directly to the leaves
Foot-candle - a unit of measure of the intensity of light falling on a surface, equal to one lumen per square foot and originally defined with reference to a standardized candle burning at one foot from a given surface
Force - to bring a plant into early growth, generally by raising the temperature or transplanting it to a warmer situation. Tulips and paper whites are examples of plants that often are forced
Forcing - manipulation of environmental factors which makes it possible to produce a marketable pot plant or cut flower out of season
Form - a naturally occurring characteristic different from other plants in the same population; growth habit (shape) of a plant
Formal - a garden that is laid out in precise symmetrical patterns; a flower, such as some camellias, that consists of layers of regularly overlapping petals
Foundation seed - seed stock handled to most nearly maintain specific genetic identity and purity under supervised or approved production methods certified by the agency
Frass - excrement of insect larvae
Frond - specifically, the foliage of ferns, but often applied to any foliage that looks fernlike, such as palm leaves
Frost-Free Date - average date in spring when your area no longer experiences frost and the average date in fall for when your area experiences the first frost. This date is important for knowing when to plant in spring. Knowing both spring and fall frost dates will help you determine the length of your growing season
Frost pocket - a depression in the ground into which cold air drains but from which it cannot escape, thus causing it to be an area very subject to freeze injury
Fruit - an expanded and ripened ovary with attached and subtending reproductive structures that develops after fertilization occurs
Fruit rot - decay of fruit. May be firm or soft
Fruiting body - any spore-producing structure of a fungus. Many are small and dark. Some grow on the surface of leaves or stems
Fruiting habit - location and manner in which fruit is borne on woody plants
Full Sun - 6 or more hours of direct sun a day
Full Shade - less than 4 hours of direct sun a day
Fumigation - application of a toxic gas or other volatile substance to disinfect soil or a container, such as a grain bin
Fungicide - a compound toxic to fungi
Fungus (Fungi) - a plant organism that lacks chlorophyll, reproduces via spores, and usually has filamentous growth. Examples are molds, yeasts, and mushrooms