Predicted Harvest Dates

Apple Maturity "Predicted Harvest Dates" Formula

Here are the formulas I use and an example of how to calculate for 2004.


Predicted Harvest Dates
McIntosh has 3 models, (take an average of the three)

30 day average of ((Minimum daily temp)-50) after full bloom date
Take this number and subtract from full bloom date + 120 days

For us this year
Full Bloom Date: May 5
Average 30 day (Min temp) – 50: -3
May 5 + 120 – (-3) = Sept 4

21 day total of ((Average Daily temp)-40) after full bloom date
Take this number and multiply by -.057 then + 144.5 + full bloom date

For us this year
21 day total: 396
* -.057=: -22.6
Add to May 5 + 144.5 = Sept 3

30 day total of average temp *-.058 + 226

For us this year:
30 day total of average temp: 1769
*-.058=: -102.6
Add to May 5 + 226 = Sept 5


Average these dates to get Sept 4 for Macs

Jonathan and Red Delicious
Take Average of (15 day Minimum temp-50)

For us this year = -.8
For Jons Full bloom date (May 6) +137 -.8 = Sept 20
For Reds Full bloom date ( May 6) +143 -.8 = Sept 26

Phil