It’s best to wait a few weeks after tilling before planting any seeds. The soil needs time to aerate and gather nutrients. In fact, any microorganisms you disrupted when tilling will need some extra time to reestablish themselves and develop valuable nutrients. The same goes for disking. It’s important to turn over the soil and allow it to breathe before planting. Crops can be hard on the soil and soil needs time to rest before it can effectively grow anything new.