when days to maturity are a range

I'm making a spreadsheet where I want to be able to automatically calculate the days to harvest; however, often this date is listed as a range of dates and I don't want to get all complicated with a formula that accounts for that range.

So now I'm staring at the wall trying to decide to pick the first date, the last date, or something in the middle??? I know this is a silly quandry, but I'd love to hear how everyone else trys to calculate their harvest date.

Which brings up another topic...that days to maturity aren't the same as days to harvest. And half the time, i can't find both of these pieces of info since I'm growing a lot of herbs.

ANd a third topic, some crops can be harvested over a range of dates so they'd have beginning harvest, and ending harvest, which I suppose I can just plug in as I go along.

I know this isn't an exact science, but I'd like to have a better idea of the timeline until I get it under my belt.

Thanks!

I think it's a range because so many variables come into play.  Amount of rain, sun, temperature, soil,wind, are all going to affect how long until the plant is mature.  I guess in your case, I would just try to take the middle.

These are biological systems that we are dealing with, not machines. Biology is ill suited to predictability and consistency.

If I plant Lofthouse Sweet Corn on May 5th, I expect to harvest it in 100 days.

If I plant the same sweet corn on June 15th, I expect to harvest it in 65 to 75 days.

Could I make a formula to calculate the growing degree days each week, and fit it to an algorithm to predict harvest dates more accurately? Sure could, but I'm growing like 100 species/varieties, and I'd spend half my time keeping records. I'd rather free up that record-keeping time to do things I value more, like singing, dancing, feasting, and loving.

I believe there are some instances of folkways where it's traditional to harvest a certain crop on a certain day of the calendar year... like in Japan there's a particular day in spring when the green tea picked that day is considered to be the best of the season. But it is localized to a very particular place, people and cultivar... and likely took many generations to assess the information and conclude that that day is the best for picking the tea. I think that if you are going to ritualize the harvest of a plant and stamp a date in the calendar, it should be a celebration. An observation of the peak wonderfulness of the crop. I don't think I have the ability to predict that for a bunch of plants I'm not extremely familiar with, in a place where they haven't been growing for very long.

I once made a spreadsheet garden schedule like you're describing.  Was a fun exercise but a couple years hands-on experience in the garden made me realize it was useless for forecasting anything.

The seed packets are grown, packed, and distributed nationwide.  The farm the seeds came from is likely in a totally different climate than my garden.  So when the seed packet says "50 days to maturity" - 50 of which days?  The day length in April when I start planting is 13 hours, by the end of June a day is 15 hours long, and in September/October when the bulk of my harvest is coming in, a day is down to 10 hours.  

So just the variation is day length accounts for a +/- 20% tolerance.  Which would mean a seed packet would have to list "40-60 days to maturity" which isn't even precise enough to be useful.

So I now ignore the DTM on the seed packet and simply group plants by planting date: spring/summer/fall, and season length - i.e full-season crop or succession crop.  For example corn, brussels sprouts, winter squash all take a full season for me, so I plan for those beds to be occupied.  Beets, carrots, green beans are half-season crops for me, meaning I can plan to turnover the bed once mid-season.  That's all the precision I need.  The vagaries of weather will determine exactly when each crop is ready to pick.

The other useful habit I got into was a garden journal - I use a note-taking app on my phone, but paper and pen work fine too.  I take pictures and write brief comments.  It's interesting to look back and note what a crop looked like on this date last year and two years ago.  Sometime despite having "the coldest April on record" followed by "the driest May in history", the garlic puttered right along and I harvested it on the same weekend I did last year!