How many days after rain should I wait to perform core aeration? I plan on doing it every weekend, and every weekend it rains. I called in sick today, hoping the forecast wouldn't be right--and, it rained all last night. This rain is also keeping me from performing the soil tests for lawn and garden. Everything's turning green and I am ready to get hopping. But I don't want to go putting down a lot of weed and feed et cetera without aerating and testing.