Soil Temperature Influences Planting Time

By Noel Mues, Extension Educator, Furnas County

            Check the soil temperature before planting vegetables. Stick a metal thermometer, available at most garden stores, two inches into the soil to get a reading. Since soil temperature fluctuates throughout the day, measure the temperature around 10 a.m. for most accurate results.

Plant cool-season vegetables (such as lettuce, spinach, onions, radishes and peas) when the soil temperature reaches 50 to 60 degrees F. Cool-season plants should be able to withstand late frosts, but gardeners may cover newly emerged seedlings with floating row covers of straw for extra protection on frosty nights. Uncover the plants during warm days so light can reach them. 

Warm-season plants (such as tomatoes, peppers, beans and squash) need soil temperatures from 60 – 80 degrees F to germinate well. Use a heat source at the plants’ base to speed germination of indoor transplants. Warm-season crops don’t tolerate frost, so be patient and wait until the danger of frost has passed before planting.