season A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and ...

is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. While each

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydropon ...

has a specific growing season that depends on its genetic

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

, growing seasons can generally be grouped into macro-environmental classes.

Geography

Geographic conditions have major impacts on the growing season for any given area. Latitude is one of the major factors in the length of the growing season. The further from the equator one goes, the angle of the Sun gets lower in the sky. Consequently, sunlight is less direct and the low angle of the Sun means that soil takes longer to warm during the spring months, so the growing season begins later. The other factor is altitude, with high elevations having cooler temperatures which shortens the growing season compared with a low-lying area of the same latitude.

Season extension

Locations

North America

The continental United States ranges from 49° north at the US-Canadian border to 25° north at the southern tip of the US-Mexican border. Most populated areas of Canada are below the 55th parallel. North of the 45th parallel, the growing season is generally 4–5 months, beginning in late April or early May and continuing to late September-early October, and is characterized by warm summers and cold winters with heavy snow. South of the 30th parallel, the growing season is year-round in many areas with hot summers and mild winters. Cool season crops such as peas, lettuce, and spinach are planted in fall or late winter, while warm season crops such as beans and corn are planted in late winter to early spring. In the desert Southwest, the growing season effectively runs in winter, from October to April as the summer months are characterized by extreme heat and arid conditions, making it inhospitable for plants not adapted to this environment. Certain crops such as tomatoes and melons originated in subtropical or tropical regions. Consequently, they require hot weather and a growing season of eight months or more. In colder climate areas where they cannot be directly sowed in the ground, these plants are usually started indoors in a greenhouse and transplanted outside in late spring or early summer.

Europe

The

Pyrenees The Pyrenees (; es, Pirineos ; french: Pyrénées ; ca, Pirineu ; eu, Pirinioak ; oc, Pirenèus ; an, Pirineus) is a mountain range straddling the border of France and Spain. It extends nearly from its union with the Cantabrian Mountains to ...

and

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

effectively divide Europe into two different regions. The Mediterranean, which is below the 45th parallel, has growing seasons of six months or more and is characterized by hot summers and mild winters. Precipitation mainly falls between October and March, with the summer being dry. In the southern Mediterranean, the growing season is year-round. Mediterranean vegetation is often evergreen due to the mild winters. Northern Europe ranges from the 45th parallel up past the Arctic Circle. The growing seasons are shorter due to the lower angle of the Sun and generally range from five months to as little as three in Scandinavia and Russia. The Atlantic coast of Europe is moderated considerably by humid ocean air, thus winters are mild and it is rare to see freezing weather or snow. Summers are also mild and as a consequence, many heat-loving plants such as maize will not grow in northern Europe. Further inland, away from the ocean, winters become considerably colder. Despite the short growing season in Scandinavia and Russia, the extreme length of daylight during summer (17 hours or more) allows plants to put on significant growth.

Tropics and deserts

In some warm climates, such as the

tropical savanna climate Tropical savanna climate or tropical wet and dry climate is a tropical climate sub-type that corresponds to the Köppen climate classification categories ''Aw'' (for a dry winter) and ''As'' (for a dry summer). The driest month has less than of ...

s (''Aw''), the

hot semi-arid climate A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi- ...

s (''BSh''), the

hot desert climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a dry climate sub-type in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert ...

s (''BWh'') or the

Mediterranean climate A Mediterranean climate (also called a dry summer temperate climate ''Cs'') is a temperate climate sub-type, generally characterized by warm, dry summers and mild, fairly wet winters; these weather conditions are typically experienced in the ...

s (''Cs''), the growing season is limited by the availability of water, with little growth in the dry season. Unlike in cooler climates where snow or soil freezing is a generally insurmountable obstacle to plant growth, it is often possible to greatly extend the growing season in hot climates by

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...

using water from cooler and/or wetter regions. This can in fact go so far as to allow year-round growth in areas that without irrigation could only support

xerophytic A xerophyte (from Greek ξηρός ''xeros'' 'dry' + φυτόν ''phuton'' 'plant') is a species of plant that has adaptations to survive in an environment with little liquid water, such as a desert such as the Sahara or places in the Alps or t ...

plants. In the tropical regions, the growing season can be interrupted by periods of heavy rainfall, called the rainy season. For example, in Colombia, where coffee is grown and can be harvested year-round, they don’t see a rainy season. However, in Indonesia, another large coffee-producing area, they experience this rainy season and the growth of the coffee beans is interrupted.

References

{{Authority control Agricultural terminology Horticulture Seasons