Carolyn, grapes are grown higher up partly because the air circulation is better so diseases are less. Your trellis is in a very open spot so it may not matter as much how low it is but your husband is right that grapes may end up touching the ground (and rotting). Also 6' is usually the recommended spacing for a single grapevine, not three. One way you could grow those three grapes there is to just put three stakes and grow them head-trained. That means they each will have a "head" of vines at the top 4-5' off the ground, with no trellis for any sideward growth. It may not sound like you would get any grapes but the "head" size will grow over the years. In the winter they would be pruned back to short stubs. See below for a picture of a very old vine. Head pruning was the most common grape pruning system 500 years ago but it is not so common anymore. One reason why I suggest this method is with your grapes already sprouting you don't want to move them this year but they don't look to be in a good position to do some other kind of trellis. Head-pruned vines can be planted much more closely than when training vines on a trellis. Scott Here is a link that might be useful: head-trained old vines

I actually have some everbearing strawberries growing under grape vines. The timing is fine. The grapes are just beginning to grow leaves and the strawberries are flowering right now. The berries we have harvested in the past have been quite fine. A bit of grape pruning may be needed if they become overly ambitious at blocking the sunlight. This has been a compatible combination for us. Ted

podpiper: I grow grapes using a 4 arm Kniffen system. I grow concord and Canadice that way. Many years ago I grew Reliance the same way too. My vines are 8' apart (great on concord) but too far away for Canadice. I love Canadice but it is a wimpy grower. I should have spaced the Canadice 6' apart. My memory of Reliance was that it grew much more vigorous than Canadice. For wire, I believe it is #10 or #12 guage that I used. I have the bottom wire at 3' and the top wire at 5' height. If I had to do it all over, I would put the top wire at 6'. Odd, but I find the vines on the top wire always produce more fruit than those on the bottom wire. Perhaps my wires are too close and the vines on top are shading the bottom wire too much?

Thanks Fruitnut, and glad to hear about the cane pruning since easier. Are the 'somewhat higher yields' worth the trouble of GDC? Do GDC get tangled? I don't mind building it, but I would prefer easy vine maintainance unless the yields are significantly higher with GDC (1.5-2x?), or the vigor of the vines are easier to manage with GDC. If I do the single wire (which I am leaning towards) it will be one at 6 feet, and I will have 8 foot per vine. Suggestions if that is enough room per vine? Thanks campv- I have a big spool of 9 gauge already. Why is rebar better than a heavy wire? Not having to re-tension?