Garlic Agroclimatology

Soil conditions (structure, fertility and pH) are important factors in determining how well a particular crop will grow. However, a more fundamental consideration is the climate. It has been widely accepted that hardneck garlic originated several thousands of years ago in central Asia where long cold winters, damp cool springs and warm, dry summers prevail. Since that time, garlic has been distributed and grown around the globe. Be that as it may, its agro-climatic needs have changed little. The ideal weather for growing hardneck garlic remains a moderately cold winter with good snow cover, a good amount spring and fall rain, and hot sunny summer days with cool nights.

A basic understanding of the our climate here in Potter County led us to conclude that we can reasonably expect to grow a garlic crop. A hardiness zone is a geographically defined by the minimum temperatures. The most commonly used Hardiness Zones are defined by the USDA [1]. We are located in USDA Zone 5a (-20°F to -15°F) which provides us a moderately cold winter. A good snow cover is usually essential to prevent frost penetration. Our average annual snowfall is between 24 to 36 inches. The main weather hazard in Potter County is winter freeze-thaw, usually during the January. Garlic is drought-sensitive and requires about one inch of water per week during root development (fall-planting time) and during early bulb development (spring emergence and growth). Moisture needs reduce about month before harvesting when leaves start to go yellow (die-back). Our average annual precipitation is 38 to 46 inches with a monthly average for April through June of 3 to 5 inches.

Some Agroclimatology qualities of Cousin Bob’s Garlic Farm are given below [2].

Mean Annual Precipitation 38 to 46 inches
Mean Annual Air Temperature 45 to 54 degrees F
USDA Zone 5a (-20°F to -15°F)
Average date for last / First frost May 23th / September 25th
Annual Average Snowfall 24 to 36 inches
Early Morning Temperature Observation

Agroclimatology is the study of climate as to its effect on crops; it includes, the relation of growth rate and crop yields to the various climatic factors and hence the optimum climates for any given crop. Source: wiki.answers

This ambient temperature reading was made on January 24, 2011. It correlates well with our USDA zone 5a location.  At the time, we had about one-foot of snow cover to minimize frost penetration and protect the winter-dormant garlic crop.

Climate Data Sources:

[1] The 2003 US National Arboretum “Web Version” of the USDA Plant Hardiness Zone Map

[2] The Pennsylvania State Climatologist.  The Pennsylvania State Climatologist is a service to the Commonwealth by the College of Earth and Mineral Sciences and Penn State. 


About wooleylot

Garlic Farmer
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