Information on how many weeks it takes to grow transplants is available in our January 7 newsletter at: https://hnr.k-state.edu/extension/info-center/newsletters/2020/Jan7_2020_01.pdf
Below are examples of some common vegetables grown for transplants and a recommended date for seeding. Dates are Saturdays as this is when many homeowners have the most free time. The dates are not set in stone, and a week earlier or later will not ruin the plants. Also, you may want to seed a week or two earlier if you are in southern Kansas and possibly a week later if you are in northern Kansas. Calendars can be reused year after year by a slight reset of the dates. Also keep notes on how well the transplants did so you can tweak the planting schedule. Your conditions may result in plants that need a bit more or a bit less time.