2011 Michigan peach harvest date prediction

The harvest of Michigan peaches is expected to be behind last year, but in line with the long term average.

Here is the 2011 prediction of Redhaven harvest onset for Michigan peach growing regions. The goal is to help growers, shippers, marketers and buyers plan their season. For Michigan, the start of significant peach volume is with the Redhaven season. Although the acreage of this variety in Michigan has declined with the availability of new varieties, it still is the most widely grown peach variety in Michigan and a handy benchmark time point.

The estimate is based on records collected on commercial Redhaven harvests in Berrien County since 1995. The Redhaven harvest onset model is based on weather data at the SW Michigan Research and Extension Center (SWMREC) Enviro-weather station approximately four miles southwest of Benton Harbor, Michigan. Regression analysis was used to determine a relationship between degree days and onset of harvest. The resulting predictive equation is D = -0.0386x + 234.9, r2 = 0.752, where x is the cumulative degree days (DD) base 50°F from January 1 through June 3 and D = the estimated harvest day of year (e.g. January 1 = 1 and December 31 = 365 in a non-leap year). The estimation is for the onset of the main season Redhaven harvest, not including fruit with split pits that ripen several days earlier than peaches without split pits.

For 2011, the estimated onset of Redhaven for Berrien County is predicted to be August 4, about one day earlier than the long-term average of August 3 and six days behind of last year. Over the years, the estimated harvest dates are generally within a few days of the actual observed harvest.

The model was used to estimate Redhaven harvest (non-split pit fruit) for four locations in addition to Berrien County. The spread of harvest dates are predicted to be from August 4 in the southwest corner of Michigan to August 11 at the Northwest Michigan Horticultural Research Station, northwest of Traverse City. This is in contrast to 2010 when the difference between south to north was predicted to be only four days.

In applying this model, it is important to bear in mind that site specific factors such as soil type, proximity to Lake Michigan, crop loads, cool weather shortly before harvest can affect peach ripening.  This is seen to be a generalized picture for the region, rather than a specific farm.

Table 1. Estimated Redhaven harvest onset in 2011, 2010 and 2009 for five locations based on the MSU  peach maturity prediction model.

Enviro-Weather station location Estimated harvest date for 2011 Estimated harvest date for 2010 Estimated harvest date for 2009
Bainbridge / Watervliet(Berrien County)* August 4 July 28 August 3
Sparta August 7 July 30 August 8
Romeo August 8 July 29 August 7
Hart August 9 August 1 August 10
NW Michigan Horticulture Research Station August 11 August 1 August 12

* Data for the Bainbridge / Watervliet weather station was used in 2011 due to gaps in data at the SW Michigan Research and Extension Center site.

The estimated Redhaven harvest day can also be used to approximate the harvest dates for other varieties by adding or subtracting  harvest dates relative to this reference variety (Table 2).  For example, a rough guess is that Loring, generally ripening 12 days after Redhaven will harvest approximately August 16th in Berrien County in 2011.

Table 2.  Typical yellow melting flesh peach variety harvest windows for the Michigan climate

Older peach varieties Newer varieties with significant production Newest peach varieties

Harbinger: -33*

PF-1: -30 Queencrest: -30
Harrow Diamond: -25 PF-5B: -25 Desiree                       -26 ^^
PF-5D Big                   -22 ^^
Earlystar                     -18 ^
PF Early 8 Ball            -17 ^^ 

Garnet Beauty: -10

Early Red Haven: -10

Glenglo: -13
PF-7: -10
Summer Serenade: -10
Rising Star: -8
GaLa: -8
Brightstar                    -12 ^
PF-7A Freestone          -10 ^^
PF 8 Ball                     -10 ^^
PF 11 Peach               -  4 ^^
PF 9A-007                  -  2 ^^
Redhaven: 0
Reliance                      0
Vivid                          +2
Bellaire                      +3
PF-12A                     +3
John Boy                   +3
Blazing Star                +2
Starfire                       +3
Redstar                      +3
PF 14 New Jersey       +4
PF Lucky 12               +4 ^^
PF Lucky 13               +6 ^
Glohaven                  +8
Canadian Harmony   +10
Loring                       +12
Suncrest                   +12
PF 15A                       +6
Blaze Prince               +8
Bounty                       +10
PF 17                        +12
Coralstar                   +12
Allstar                        +18
Contender                 +18
John Boy II                    +8 ^
Gloria                           +13 ^^ LA
PF 19-007                      +16 ^^
Messina                        +17 ^^
Beaumont                     +18 ^
Cresthaven                +24
Redskin                     +26
PF 23                         +20
PF 24-007                  +22
Glowingstar                +24
PF 25                         +26
PF 22-007                     +20 ^^
SweetStar                      +20 ^
July Prince                     +24 ^^
PF Lucky 24B                +24 ^
PF 24C Cold Hardy         +24^^
Madison                    +28
Harcrest                    +28
Fayette                      +28
Encore                       +31
PF 27A                      +30
Laurol                        +41
PF 28-007                      +32 ^^
Autumn Star                    +37 ^^
Flame Prince                   +38 ^^
PF 35-007 Fat Lady         +40 ^^
Victoria                            +47 ^^
PF Big George                +56^^

* = estimated harvest days before (-) or after Redhaven. A cooler year will delay harvest dates, a warmer season will compress the harvest dates closer together.  ^ = little experience with this variety to date, ^^ = very little experience to date. LA = low acid type

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