The Growing Temperature for Cucumbers

Germination

• Cucumber seeds germinate at a temperature from 50 to 105 degrees Fahrenheit. According to Cornell University Extension, however, it is best to wait until soil reaches a temperature of 65 F before you sow the seeds. Germination time decreases with higher temperatures, with optimal germination occurring at 80 to 90 degrees. At those temperatures, seeds germinate in three days, whereas seeds planted in cooler soil may not germinate for 10 or more days.

Seedlings

• Cucumber seedlings do not tolerate cold spring breezes or chilly nights. Transplant cucumber seedlings to a garden after all danger of frost passes. Although seedlings will survive as long as temperatures are above freezing, their growth is slowed or inhibited if temperatures remain below 70 F during the day or below 60 F at night.

Growth

• Cucumber plants prefer temperatures from 70 to 95 F but require supplemental watering as the temperature soars. They consume large amounts of water to support their massive vines and prolific fruit. As the temperature rises, step up supplemental watering to keep up with their needs. When their soil feels dry, provide enough water for it to reach 1 inch below the surface of the soil.

Techniques

• Warming garden soil in early spring provides a head start on the growing season. Spreading black plastic over the soil as soon as it is tilled will warm the soil. Once the soil is warm, cut holes in the black plastic and plant cucumbers in the holes. Covering young cucumbers with floating row-over or protective caps until the outside temperature remains in the 70s F is beneficial.