North American Fruit Explorers mailing list at ibiblio

["Lon J. Rombough" <lonrom@hevanet.com>]

Title: Re: [NAFEX] Grapes for No. IL

One of the most important aspects of hardiness in grapes is how much time the vine has to harden off.  If frost comes very soon after harvest, the vines have little time to complete hardening and may be damaged considerably by even the first frost.  I've had vines die back almost to the old wood simply because early frost took the leaves off before the vines finished hardening.  That's what makes it so hard to predict the ultimate hardiness of a variety.  Vanessa is rated as hardy to -20 at Vineland, where it came from, but they have several weeks of frost free season after harvest, and the winter cold sets in more gradually.  I would take off as much as ten degrees hardiness if frost comes less than two weeks after harvest, and even more if strong cold comes in November.  "Strong" meaning anything below 10 F.  
    Of course how you take care of the vine helps, too.  For instance, overcropping is a good way to weaken a vine and reduce it's cold hardiness considerably.
    Interlaken is one that ripens very early, which gives it more time to pump sugars into the wood after harvest, so it is able to reach it's full (if modest) hardiness more readily.
    -Lon Rombough
Grapes, writing, consulting, my book, The Grape Grower, at http://www.bunchgrapes.com
Winner of the Garden Writers Association "Best Talent in Writing" award for 2003 


> Hi Doreen, 
>
> I have lost my Vanessa due to low winter temps.  Dies off to the ground.  Being from Massachusetts, I can say our winters here are the same as yours. 
>
> Dou you want to invest 4 years in a vine, to have an oddly cold winter kill it off? 
>
> Later, 
> Tom 
>
> Doreen Howard wrote: 
> > Lon and I have been discussing what seedless grapes I should plant in my new paradise 75 miles west of Chicago near the Wisconsin border.  He tells me that some of my choices may have disease problems here.  But......don't take this personally Lon...he grows his grapes in a different climate than I do.  So, Zone 5a and 4b Midwest grape growers, I need your opinions. How will the following seedless grapes do here: InterlakenVanessaGlenoraMars My area hits -20F one out of five winters, and annual rainfall is about 30 inches.  Late summers are typically hot and very dry.  I'm an organic gardener and have beautiful loam soil.  I'll be planting the grapes facing south on a slope.  Air movement is brisk.Doreen Howard