Definitions

growing season

growing season

growing season, period during which plant growth takes place. In temperate climates the growing season is limited by seasonal changes in temperature and is defined as the period between the last killing frost of spring and the first killing frost of autumn, at which time annual plants die and biennials and perennials cease active growth and become dormant for the cold winter months. In tropical climates, in which there is less seasonal temperature change, the amount of available moisture often determines the periods of plant growth; in the rainy season growth is luxuriant and in the dry season many plants become dormant. In desert areas, growth is almost wholly dependent on moisture. In the Arctic the growing season is short but concentrated; the number of daylight hours is so large that the total amount of sunlight equals that of a temperate growing season with shorter days. The length of the growing season often determines which crops can be grown in a region; some require long growing seasons and others mature rapidly. Plants that are perennials in a warm climate may sometimes be grown as annuals in cooler areas; by crossing hardy plant species with less hardy but more productive types, plant breeders have developed desirable new strains that mature in a shorter period. Combinations of factors affect the growing season; in the sheltered valleys and coastal slopes of the Pacific Northwest of the United States, the heavy winter rainfall and the dry summers have produced a Mediterranean type of climate where plant growth occurs during the winter and dormancy during the summer. See climate; seasons.

Period of the year, also called frost-free season, during which growing conditions for native vegetation and cultivated crops are the most favourable. It usually becomes shorter as distance from the equator increases. In equatorial and tropical regions the growing season ordinarily lasts all year; at higher latitudes (e.g., the tundra), it may last as little as two months or less. It also varies according to elevation above sea level: higher elevations tend to have shorter growing seasons.

Learn more about growing season with a free trial on Britannica.com.

In agriculture, the growing season is the period of each year when crops can be grown. It is usually determined by climate and crop selection. Depending on the location, temperature, daylight hours (photoperiod), and rainfall, may all be critical environmental factors.

In the northern U.S. and Canada, the growing season usually means the days between last and first frost, or approximately the last and first occurrence of 0° C (freezing) overnight low temperature. This is roughly May to October.

In much of Europe, the growing season is defined as the average number of days a year with a 24-hour average temperature of at least 5 °C (6 °C is sometimes used). This is typically from April until October or November, although this varies considerably with latitude and altitude.

In the United Kingdom, the growing season is defined as starting when the temperature on five consecutive days exceeds 5 °C, and ends after five consecutive days of temperatures below 5 °C. The 1961 to 1990 average season length was 252 days (8.4 months).

In some warm climates (like in the subtropical Savanna), the growing season is limited by the availability of water, with little growth in the dry season.

See also

References

Search another word or see growing seasonon Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature