I think I'm ready.
Growing Grapes in Zone 4b/5aConsiderations:
SiteSince grapes will be a long-lived plant, I needed to consider the site similar to my fruit tree plantings. I want to keep the grapes close to the garden. This will provide easy access for irrigation, pest control, early-season access for pruning and maintenance, and access for mechanical assistance (garden tractor & cart for hauling away prunings, fruit, etc. Lots of sites suggest southern slopes (but I only have northern slopes), or other south exposures (but my south exposure is in a low spot & tends to freeze early). I've chosen, instead, an area parallel to one edge of my garden, in a slightly elevated bed that I have used and not used for years. It is currently getting reclaimed from the latest weeds & I think grapes would be a good plant to establish in part of this bed. New topsoil will need to be brought in this fall, or at least a large quantity of compost (which I have cooking nearby).
CultivarsAsk any two people what grapes are best to grow & you'll get 7 different opinions.
Resources to help choose grape cultivars:
Home Fruit Cultivars for Northern Wisconsin (use the View PDF button to view online)
Home Fruit Cultivars for Southern Wisconsin (use the View PDF button to view online)
Growing Grapes for Home Use - Minnesota (has a really nice comparison chart)
Of course, check with your local nursery...if you can't seem to find a grape you were searching for, perhaps it doesn't grow well in your area!
The "Short List" of cultivars I'm planning:
Cultivar Use Ripen Color Hardiness(5a)
Edelweiss T,W,(J) early-mid White Moderate
Himrod Seedless T* early White Moderate
Marquette W Red Hardy
Reliance Seedless T*,J,(W) mid-late Red Hardy
Swensen Red T mid Red Moderate
Valiant T,J early Blue Hardy
There has been some confusion on the hardiness of specific cultivars. For example, Himrod was listed as "Tender" by U-MN, but "Very Hardy" by a U-WI test planting. In other words, I'm guessing.
TrellisingGrapes need trellises. That much everyone agrees upon. Having spent the better part of a week investigating the options, I'm no better off than simply picking one that sounds good.
Since my initial planting will have limited space (maybe 30' of row total, 6' horizontal spacing), I've chosen to make my trellises out of 8ft. T-posts & 9-ish gauge wire. I don't really need to worry about fancy anchoring of the rows, but the wire does need to have a tensioner (I will use a turnbuckle) to accommodate varying loads on the wire. I'm planning on using 3 posts, since the recommended spacing is no more than ~28 feet, and I like to over-design things anyhow.
The training system I'm planning to use is the Umbrella Kniffen, which seems to be a good system for the novice home grower still learning to prune. The vine grows vertically & shoots are looped over a wire ~6ft above ground level, then brought back down and tied to a wire ~3.5ft above ground level. Several publications explore this in detail, one is:
Growing Grapes in Wisconsin (use View PDF button to view online)
IrrigationI'm lazy. I run my garden on two sprinklers with automatic timers. The grapes will be no different, though I'm considering a dedicated drip irrigation line for the vines, integrated in the trellis. An extra wire 1.25ft above ground level will provide an anchor point for a drip irrigation line. Two 1GPH drip emitters per vine will be placed 10-12 inches to either side of the main trunk. This irrigation line will run separate from the garden system, providing deep watering for the grapes.
Schedule:2013 - Fall Site preparation, add compost, install trellis posts and wires
2014 - Spring Purchase and plant vines, install stakes for main trunk, begin training
2015 - Spring Continue training
2016 - Spring Continue training
2016 - Fall light harvest (maybe, depends on age of vines purchased)
2017 - Spring Continue training
2017 - Fall Harvest