Crimson or red clover can sprout quickly with the first light rain. If they stay damp for a couple days they are fine. If they bake in the sun with no rain for a few weeks they can die. Smaller clover seed like ladino or dutch white can take 3-7 days to sprout, so they usually wait for better conditions. Red clovers/crimson grow very quickly, perennial white clovers take there time, but are worth the wait.