Growing degree day

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Growing degree day

Growing degree days (GDD) are a heuristic

Heuristic

Heuristic is an adjective for methods that help in problem solving, in turn leading to learning and discovery. These methods in most cases employ experimentation and trial-and-error techniques....
tool in phenology

Phenology

Phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate....
. GDD are used by horticulturists

Horticulture

'Horticulture' is the industry and science of plant cultivation. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, Crop , plant breeding and genetic engineering, plant biochemistry, and plant physiology....
and gardeners to predict the date that a flower will bloom or a crop reach maturity.

In the absence of extreme conditions such as unseasonal drought

Drought

A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation ....
or disease, plants grow in a cumulative stepwise manner which is strongly influenced by the ambient temperature. Growing degree days take aspects of local weather

Weather

Weather is a set of all the Phenomenon occurring in a given atmosphere at a given time. Weather phenomena lie in the hydrosphere and troposphere....
into account and allow gardeners to predict (or, in greenhouse

Greenhouse

A greenhouse is a building where plants are cultivated.A greenhouse is a structure with a glass or plastic roof and frequently glass or plastic walls; it heats up because incoming solar radiation from the sun warms plants, soil, and other things inside the building....
s, even to control) the plants’ pace toward maturity.

are calculated by taking the average of the daily maximum and minimum temperatures compared to a base temperature, T_base, (usually 10 °C).

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Encyclopedia

Growing degree days (GDD) are a heuristic

Heuristic

Phenology

Phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate....
. GDD are used by horticulturists

Horticulture

Drought

Weather

Greenhouse

GDD calculation

GDD are calculated by taking the average of the daily maximum and minimum temperatures compared to a base temperature, T_base, (usually 10 °C). As an equation:

GDDs are typically measured from the winter low. Any temperature below T_base is set to T_base before calculating the average. Likewise, the maximum temperature is usually capped at 30 °C because most plants and insects do not grow any faster above that temperature. However, some warm temperate and tropical plants do have significant requirements for days above 30 °C to mature fruit or seeds.

For example, a day with a high of 23 °C and a low of 12 °C would contribute 7.5 GDDs.

A day with a high of 13 °C and a low of 10 °C would contribute 1.5 GDDs.

Plant development

Common name	Latin name	Number of growing degree days baseline 10 °C
Witch-hazel Witch-hazel Witch-hazel is a genus of flowering plants in the family Hamamelidaceae, with two species in North America , and one each in Japan and China ....	Hamamelis spp.	begins flowering at <1 GDD
Red maple Red Maple *Acer rubrum* , is one of the most common and widespread deciduous trees of Eastern United States North America. It ranges from the Lake of the Woods on the border between Ontario and Minnesota, east to Newfoundland and Labrador, south to near Miami, Florida, Florida, and southwest to east Texas....	Acer rubrum	begins flowering at 1-27 GDD
Forsythia Forsythia *Forsythia* is a genus of flowering plants in the family Oleaceae . There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe....	Forsythia spp.	begin flowering at 1-27 GDD
Sugar maple Sugar Maple *Acer saccharum* is a species of maple native to the hardwood forests of northeastern North America, from Nova Scotia west to southern Ontario, and south to Georgia and Texas....	Acer saccharum	begin flowering at 1-27 GDD
Norway maple Norway Maple *Acer platanoides* is a species of maple native to eastern and central Europe and southwest Asia, from France east to Russia, north to southern Scandinavia and southeast to northern Iran....	Acer platanoides	begins flowering at 30-50 GDD
White ash White Ash *Fraxinus americana* is a species of Fraxinus native to eastern North America found in mesophytic hardwood forests from Nova Scotia west to Minnesota, south to northern Florida, and southwest to eastern Texas....	Fraxinus americana	begins flowering at 30-50 GDD
Crabapple	Malus spp.	begins flowering at 50-80 GDD
Common Broom	Cytissus scoparius	begins flowering at 50-80 GDD
Horsechestnut Aesculus The genus *Aesculus, the buckeyes* and Horse Chestnuts, comprises 13-19 species of woody trees and shrubs native to the temperate northern hemisphere, with 6 species native to North America and 7-13 species native to Eurasia; there are also several Hybrid ....	Aesculus hippocastanum	begin flowering at 80-110 GDD
Common lilac Lilac *Syringa* is a genus of about 20?25 species of flowering plants in the olive family , native to Europe and Asia.They are deciduous shrubs or small trees, ranging in size from 2?10 m tall, with stems up to 20?30 cm diameter....	Syringa vulgaris	begin flowering at 80-110 GDD
Beach plum Plum A plum or gage is a drupe tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and the side buds solitary , the flowers being grouped 1-5 together on short stems, and the fruit having a groove running down one side, and a smooth stone....	Prunus maritima	full bloom at 80-110 GDD
Black locust Black locust *Robinia pseudoacacia, commonly known as the Black Locust*, is a tree in the subfamily Faboideae of the pea family Fabaceae. It is native to the southeastern United States, but has been widely planted and naturalisation elsewhere in temperate North America, Europe and Asia and is considered an invasive species in some areas....	Robinia pseudoacacia	begins flowering at 140-160 GDD
Catalpa Catalpa Catalpa, also spelled Catawba, is a genus of mostly deciduous trees in the flowering plant family Bignoniaceae, native to warm temperate regions of North America, the West Indies, and eastern Asia....	Catalpa speciosa	begins flowering at 250-330 GDD
Privet Privet Privet was originally the name for the European semi-evergreen shrub Ligustrum vulgare, and later also for the more reliably evergreen Ligustrum ovalifolium , used extensively for privacy hedging ....	Ligustrum spp.	begins flowering at 330-400 GDD
Elderberry Elderberry *Sambucus* is a genus of between 5 and 30 species of shrubs or small trees, formerly placed in the honeysuckle family, Caprifoliaceae, but now shown by genetic evidence to be correctly classified in the moschatel family, Adoxaceae....	Sambucus canadensis	begins flowering at 330-400 GDD
Purple loosestrife Purple loosestrife *Lythrum salicaria* is a flowering plant belonging to the family Lythraceae, native to Europe, Asia, northwest Africa, and southeastern Australia....	Lythrum salicaria	begins flowering at 400-450 GDD
Sumac Sumac Sumac is any one of approximately 250 species of flowering plants in the genus Rhus and related genera, in the family Anacardiaceae. The dried berries of some species are ground to produce a tangy purple spice....	Rhus typhina	begins flowering at 450-500 GDD
Butterfly bush Butterfly bush The common name "Butterfly Bush" refers to several different species.Examples include:Clerondendron ugandensBuddleia davidiiBuddleia globosaother Buddleias...	Buddleia davidii	begins flowering at 550-650 GDD
Corn (maize) Maize Maize , known as corn in some countries, is a cereal domesticated in Mesoamerica and subsequently spread throughout the American continents....	Zea mays	1360 GDD to crop maturity
Dry bean Bean Bean is a common name for large plant seeds of several genus of the Family Fabaceae used for human food or animal feed.The whole young pods of bean plants, if picked before the pods ripen and dry, can be tender enough to eat whole, whether cooked or raw.... s	Phaseolus vulgaris	1100-1300 GDD to maturity depending on cultivar Cultivar A cultivar is a cultivated plant that has been selected and given a unique name because of its decorative or useful characteristics; it is usually distinct from similar plants and when Plant propagation it retains those characteristics.... and soil conditions
Sugar Beet Sugar beet Sugar beet , a member of the Chenopodiaceae family, is a plant whose root contains a high concentration of sucrose. It is grown commercially for sugar production....	Beta vulgaris	130 GDD to emergence and 1400-1500 GDD to maturity
Barley Barley Barley is an annual plant cereal grain derived from the grass *Hordeum vulgare*. It serves as a major animal feed crop, with smaller amounts used for malting and in health food, as well as the making of alcoholic beverages beer and whisky....	Hordeum vulgare	125-162 GDD to emergence and 1290-1540 GDD to maturity
Wheat Wheat Wheat , is a worldwide cultivated Poaceae from the Levant region of the Middle East. Globally, after maize, wheat is the second most-produced food among the cereal just above rice.... (Hard Red)	Triticum aestivum	143-178 GDD to emergence and 1550-1680 GDD to maturity
Oat Oat The common oat is a species of Cereal Agriculture for its seed, which is known by the same name . While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed.... s	Avena sativa	1500-1750 GDD to maturity
European Corn Borer European Corn Borer The European Corn Borer is a pest of grain, particularly maize. The insect is native to Europe originally infesting varieties of millet including broom corn....		207 - Emergence of first spring moths

Insect
Insect

Insects are the biggest class of arthropods and the only ones with wings. They are the most diverse group of animals on the planet. They are most diverse at the equator and their diversity declines toward the poles....
development and pest control
Pest control

Pest control refers to the regulation or management of a species defined as a pest , usually because it is perceived to be detrimental to a person's health, the ecology or the Economics....

Growing degree days are also used by some farmer

Farmer

A farmer is a person who raises living organisms for food or raw materials....
s to time their use of pest controls so they are applying the treatment at the point that the pest is most vulnerable. For example:

Black cutworm larvae have grown large enough to start causing economic damage at 165 GDD
Azalea Lace Bug emerges at about 130 GDD
Boxwood leaf miner emerges at about 250 GDD

Several beekeeper

Beekeeper

A beekeeper is a person who keeps honey bees for the purposes of securing commodities such as honey, beeswax, pollen; pollination fruits and vegetables; raising Queen and bees for sale to other farmers; and/or for purposes satisfying natural scientific curiosity....
s are now researching the correlation between GDD and the lifecycle of a honeybee colony.

Baselines

10 °C is the most common base for GDD calculations, however, the optimal base is often determined experimentally based on the lifecycle of the plant or insect in question.

5.5 °C wheat
Wheat

Wheat , is a worldwide cultivated Poaceae from the Levant region of the Middle East. Globally, after maize, wheat is the second most-produced food among the cereal just above rice....
, barley
Barley

Barley is an annual plant cereal grain derived from the grass Hordeum vulgare. It serves as a major animal feed crop, with smaller amounts used for malting and in health food, as well as the making of alcoholic beverages beer and whisky....
, rye
Rye

Rye is a Poaceae grown extensively as a grain and forage crop. It is a member of the wheat tribe and is closely related to barley and wheat. Rye grain is used for flour, rye bread, rye beer, some rye whiskey, some vodkas, and animal fodder....
, oat
Oat

The common oat is a species of Cereal Agriculture for its seed, which is known by the same name . While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed....
s, flaxseed, lettuce
Lettuce

Lettuce is a temperate annual plant or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold, raw, in salads, hamburgers, tacos, and in many other dishes....
, asparagus
Asparagus

Asparagus officinalis is a flowering plant species in the genus Asparagus from which the vegetable known as asparagus is obtained....
6 °C stalk borer moth
7 °C Corn rootworm
8 °C sunflower
Sunflower

The sunflower is an annual plant in the family Asteraceae and native to the Americas, with a large flowering head . The stem can grow as high as 3 meters , and the flower head can reach 30 cm in diameter with the "large" seeds....
, potato
Potato

The potato is a starchy, tuberous crop from the perennial plant Solanum tuberosum of the Solanaceae family. The word potato may refer to the plant itself as well....
9 °C Alfalfa weevil
10 °C maize
Maize

Maize , known as corn in some countries, is a cereal domesticated in Mesoamerica and subsequently spread throughout the American continents....
(including sweet corn), sorghum
Sorghum

Sorghum is a genus of numerous species of Poaceae, some of which are raised for grain and many of which are used as fodder plants either cultivated or as part of pasture....
, rice
Rice

Rice is a staple food for a large part of the world's human population, especially in tropical Latin America, and East Asia, South Asia and Southeast Asia, making it the second-most consumed cereal grain, after maize....
, soybeans, tomato
Tomato

The Tomato is an herbaceous, usually sprawling plant in the Solanaceae or nightshade family, as are its close cousins Nicotiana, potatoes, aubergine , chilli peppers, and the poisonous Atropa belladonna....
, Black cutworm, European Corn Borer
European Corn Borer

The European Corn Borer is a pest of grain, particularly maize. The insect is native to Europe originally infesting varieties of millet including broom corn....
, standard baseline for insect and mite pests of woody plants
11 °C Green Cloverworm
12 °C many other crop calculations
30 °C the USDA
United States Department of Agriculture

The United States Department of Agriculture is the United States federal executive departments responsible for developing and executing Federal government of the United States policy on farming, agriculture, and food....
measure heat zones in GDD above 30 °C; for many plants this is significant for seed maturation, e.g. reed
Phragmites

Phragmites australis, the common reed, is a large perennial plant Poaceae found in wetlands throughout temperate and tropical regions of the world....
(Phragmites) requires at least some days reaching this temperature to mature viable seeds

GDDs may be calculated using either Celsius or Fahrenheit, though they must be converted appropriately; 5 GDD^C = 9 GDD^F

Growing degree day

GDD calculation

Plant development

Baselines

See also

Bibliography External links