.Well that depends. To "till", is to prepare soil for crops, you can till the soil. But "till" and "until" really mean the same thing when used in the context of time. Sometimes people write 'til, and that is the spoken and shortened version of "until". The only thing to watch out for, is it is not common nor does it sound correct to start a sentence with "till," rather use "until." Actually, just always use until to be safe.

Till, or 'till is just a shortened and less formal way of writing or saying the word until. (only 1 L) example: "until we meet again"