How Long Does it Take for Cucumber Seeds to Germinate?

Cucumber plants are vining plants commonly grown by home gardeners. Home gardeners may start the seeds themselves as a more cost effective way to produce plants for their gardens. You can start cucumber seeds through direct seeding or planting the seeds indoors in a seed tray to get a head start on the garden. Germination times for cucumber seeds depend greatly on the soil and air temperature.

Cucumber seeds only germinate in warm weather conditions.

Soil Temperature

The ideal soil temperature for cucumber seed germination is between 70 and 85 degrees Fahrenheit. The soil should be within this temperature range regularly. Cucumber seeds can germinate at soil temperatures that are at least 60 degrees Fahrenheit, but this is not an ideal temperature, and there is a greater likelihood that the seeds will not germinate. If there is even a slight frost or a prolonged dip in temperature, then the seeds may need to be replanted.

Air Temperature

The ideal air temperature for a cucumber seed to germinate is between 75 and 95 degrees Fahrenheit. However, cucumber seeds can germinate in air temperatures that are 65 to 70 degrees Fahrenheit. The lower the air temperature, the longer the germination period. Cucumbers are a warm-weather vegetable so they will not tolerate prolonged cold weather conditions or even a light frost.

Germination Time

If there are both ideal soil and air temperatures, cucumber seeds germinate in seven to 10 days. If the soil and air temperatures are lower than the optimal temperatures, or are on the lower end of the ideal temperature ranges, then the cucumber seeds take longer to germinate. In colder conditions, the germination time can be up to three weeks.

Water Germination

You can germinate cucumber seeds by direct seeding into a home garden bed or in soil in a seed tray. However, cucumber seeds can also be started with only water, as long as the temperatures are sufficiently high. This is a very quick method of germinating cucumber seeds, although the cucumber seeds germinated in this manner may not be as hardy as those that have germinated in soil. To germinate cucumber seeds using water, wrap the cucumber seeds in a wet paper towel and place in a shallow bowl. Cover the bowl with plastic wrap, and leave it in a sunny and warm space. The cucumber seeds can germinate in as short a period as three days.