Figure 1 Purdue agricultural centers
Soil temperatures are critical for seed germination and are closely related to occurrences of some early season soilborne disease and pest problems on vegetable crops. Plant vegetable crops after the soil is warm enough ensure good seed germination and fast crop establishment. The figures below show daily average soil and air temperatures at recorded at six locations (Figure 1) in Indiana from April 25 to May 8 that maybe helpful in assessing soil conditions for planting across the state. More information regarding recommended soil temperatures for vegetable planting can be found in the articles https://www.hort.purdue.edu/ext/ho-186.pdf and https://vegcropshotline.org/article/seedcorn-maggots-and-wireworms/
Figure 2. Daily air and soil temperatures from April 25 to May 8.