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Weather data for Sanford ME.  Forecast values begin September 20, 2011
Preliminary McIntosh Harvest Date Forecasts
CAUTION:  The estimates shown below are appropriate for long-term planning only.  Harvest decisions should only be made on basis of direct orchard observations.  Accuracy of these apple maturity estimates can vary between orchards and between years in a single orchard. 
Harvest date estimates are based on temperature observations from the first 30 days after Full bloom.  Estimates for this location are based on incomplete data until Tuesday, June 21.
     
      To delay the entire harvest period (1st and later picks) up to 7-10 days, apply ReTain 28 days prior to beginning of expected harvest date for untreated fruit. 
      To improve fruit quality and storage potential of later picked apples (2nd, 3rd, 4th picks), apply ReTain 7 to 14 days prior to beginning of expected harvest date for untreated fruit.  This later timing typically will not delay the start of harvest (1st pick), but will delay maturity for later picks.

Date to apply ReTain to delay first harvest for apples which without treatment would be ready for storage harvest on September 14 is
Wednesday, August 17
Begin measuring actual McIntosh starch-iodine index no later than
Friday, August 26
    The McIntosh maturity date estimate shown below is a preliminary, early-season forecast and in no way a substitute for starch index and other direct observations as harvest nears.
The Michigan formula estimates that non-spur McIntosh will reach starch index 4.0 and start the optimum harvest window for long term storage on
Friday, September 16.   
    Cornell Bulletin 221 provides formulas for different locations to estimate date when
non-spur McIntosh not treated with ReTain will reach starch index 6.0 and the end of the optimum harvest window for long term storage.
Using the Champlain Valley NY formula,
McIntosh maturity is forecast to reach starch index 6.0 in
 Sanford ME on Friday,  September 23