Start counting from seed planting date. But beware, the days to harvest (DTH) is only an average. Some of the other variables are - your planting zone, weather, soil conditions, planting date; these will impact your DTH... For example, my Early April 2013 planted corn had about a 72 DTH; the May planted corn had a 68 DTH, the June planted corn had 58 DTH. My corn harvest is typically 3 to 4 weeks after tassel and 2 to 3 weeks after silks form.

I think it is from when it comes up, for corn. How much did you plant that you need a vacation to process it?

I count it from the seeding date.

OK, so counting days on the calendar, that puts it August 11 for 78 days. So that helps me to plan a little better. I don't have to put in for the exact dates off right now but I do have to let my boss know about when - so it will be sometime the 2nd week of August. I know what we have planted is probably not a big deal for most people - 4 30' rows, but for us old folks who move slower these days and working 12 hours a day by the time I add in my drive time, there is not enough time between when I get home and have to go to bed to do anything. Thus I will need a day or so to get it all picked and processed. Then I might need a vacation from my vacation to get rested up!!! :^)
Thanks all for your help.
Edie

Sweet corn can take either longer or shorter time than listed DTM. April plantings may take a week longer and June plantings can take a week less with really warm weather.