Necessity of hilling up for winter

[CTDrew]

I am planning a little expansion into some Cab Franc this coming year. I will be adding 50 vines of clone 1 to my hobby vineyard. I have a nice site with a sandy soil here in the CT river valley. I am in zone 6B on the new USDA zones. I am wondering if it is worth the effort to hill these up for protection in the winters or not. A commercial vineyard about 30 miles north hills up(zone 6A), and some about 40 miles south do not(zone 6B but closer to the 7A line than I am). I have a few Riesling vines that I have never had an issue with, and which I do not protect for winter. I was just wondering if anybody in a similar zone in the northeast had thoughts on what they do.

 

[Obbnw]

I am planning a little expansion into some Cab Franc this coming year. I will be adding 50 vines of clone 1 to my hobby vineyard. I have a nice site with a sandy soil here in the CT river valley. I am in zone 6B on the new USDA zones. I am wondering if it is worth the effort to hill these up for protection in the winters or not. A commercial vineyard about 30 miles north hills up(zone 6A), and some about 40 miles south do not(zone 6B but closer to the 7A line than I am). I have a few Riesling vines that I have never had an issue with, and which I do not protect for winter. I was just wondering if anybody in a similar zone in the northeast had thoughts on what they do.

I'm not in the northeast but am in a similar zone. I think when you are on the cusp or pushing the limits of the zones, your local microclimate will have a major effect.

My vines are fairly well protected, I don't have cold pools, and have decent thermal mass in walls and buildings that the vines are on so I don't worry too much. I've got a friend who is officially in the middle of a 7A zone, but his local microclimate is more like a 5A or B. He is at the bottom of the valley just uphill from the highway that essentially acts like a dam for the cold air. On cold clear nights he gets -20 temps when I have 10.

Just down the street from me is a school with a big detention basin to store runoff from heavy rains. It's mostly dry and has grass in it. In the evenings that depression can easily run 10-15 degrees cooler than the air just 50' away on the top of the berm.

So take a look around - will the cold pool? is the area protected? Any local factors that might make it warmer or colder?

Historically we have the potential for -20 temps at my house. My plan for that unlikely scenario is Christmas lights and tarps. I already have Christmas lights on 2/3 of my vines and think I have enough tarp to cover about 2/3 of the grapes with Christmas lights. Plus I have some additional lights I could add to unlighted ones. If I'm paying attention I think I can easily save half the vines and If I'm lucky more...

 

[mbrssmd]

I'm not in the northeast but am in a similar zone. I think when you are on the cusp or pushing the limits of the zones, your local microclimate will have a major effect.

My vines are fairly well protected, I don't have cold pools, and have decent thermal mass in walls and buildings that the vines are on so I don't worry too much. I've got a friend who is officially in the middle of a 7A zone, but his local microclimate is more like a 5A or B. He is at the bottom of the valley just uphill from the highway that essentially acts like a dam for the cold air. On cold clear nights he gets -20 temps when I have 10.

Just down the street from me is a school with a big detention basin to store runoff from heavy rains. It's mostly dry and has grass in it. In the evenings that depression can easily run 10-15 degrees cooler than the air just 50' away on the top of the berm.

So take a look around - will the cold pool? is the area protected? Any local factors that might make it warmer or colder?

Historically we have the potential for -20 temps at my house. My plan for that unlikely scenario is Christmas lights and tarps. I already have Christmas lights on 2/3 of my vines and think I have enough tarp to cover about 2/3 of the grapes with Christmas lights. Plus I have some additional lights I could add to unlighted ones. If I'm paying attention I think I can easily save half the vines and If I'm lucky more...

I would endorse the good advice by Obbnw on doing a close assessment of multiple factors that make up your microclimate situation. I’m often startled to come upon the differences on our property that 20 yards and a slight shift in slope can make.

Here in northern Maryland, just south of Gettysburg, the USDA just moved us from 6B to 7A. In the past 8 years of growing cab franc we had a handful of single digit below zero nights. I’ve never hilled our 50 CF vines, and have had no problem (save for the “Mother’s Day Massacre” frost a few years back but that’s a different kettle of dead fish...).

In my experience, again in this climate here, there is a strong need to make sure the vines truly shut down and go completely dormant for the winter. Otherwise, CF can be notoriously eager post-winter solstice in wanting to start their reawakening in anticipation of spring.

How much drainage provided by your sandy soil may be a factor to consider (in terms of helping that shutdown especially if it is a wet autumn). I would add that for CF good drainage (and limited soil fertility) are also key factors in minimizing generally unwanted herbaceous flavor notes.

 

[TurkeyHollow]

I am planning a little expansion into some Cab Franc this coming year. I will be adding 50 vines of clone 1 to my hobby vineyard. I have a nice site with a sandy soil here in the CT river valley. I am in zone 6B on the new USDA zones. I am wondering if it is worth the effort to hill these up for protection in the winters or not. A commercial vineyard about 30 miles north hills up(zone 6A), and some about 40 miles south do not(zone 6B but closer to the 7A line than I am). I have a few Riesling vines that I have never had an issue with, and which I do not protect for winter. I was just wondering if anybody in a similar zone in the northeast had thoughts on what they do.

Are they grafted root vines or just hybrid? A graft should be covered to protect it from the cold. If hybrid, you can double-trunk as an insurance policy against freeze damage.

 

[CTDrew]

These are grafted cab franc, not own rooted. I figure it might be wise to at a minimum cover the graft unions for the winter and likely that is what I will do. I was out visiting a few cab franc plantings west of me in the Hudson Valley of NY this past weekend, and one vineyard had gone through with a grape hoe and hilled up (like one of my local vineyards does, and like the growers in the Finger Lakes do) the other two did not. I asked my question to the vineyard manager at one of the sites that doesn’t hill up and he told me they determined it was cheaper at their site to replace a vine here and there versus the time to use the grape hoe. I did note that there were numerous obvious replacements in their vineyard so they have had some freeze kill. I suspect that as others have said the necessity of hilling up will be site specific. I have good air drainage on my site. I am on a plateau that is slightly pitched toward a very steep southerly escarpment (drops 90 feet of elevation over about 100 feet of distance. This area of the property is always the last place to get a frost. Not sure I will rely solely on that though, given the time to set up the planting!

 

[TurkeyHollow]

I (also in zone 6b) have grafted vines and covered the unions the first couple of years then decided to "roll the dice" with a few vines and was lucky (even in a somewhat cold winter). I have not covered them since. I've not yet lost a single grafted vine due to cold damage. I don't know if the variety makes any difference but these are Chardonel (a white) which are mid-wire cordon. Also fairly good drainage, they are planted in North-South rows on a slightly sloping grade facing west. We had more problems with powdery and downy mildew than anything last growing season due to all rain (after the dry start). Keep posting though - it's always good to hear what other growers in the area are experiencing.