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How important is late afternoon, mid-late season sun?

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Kilohertz

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In planing my vineyard, where I wanted to put it, I can only fit in 20 vines, maybe 26 if I add another row. So now I need to find another location to expand to. On the other side of the property is an old raspberry garden, which was built years ago and was all set up with posts and trellis wires but has long since rotted away, plants are long gone, but the ground is nice, grass growing with really no weeds to speak of, probably large enough to plant 50 vines, but I don't need that many. :rolleyes:

My only concern is the grove of tress to the west, which right now is beginning to shade the western part of the field about 5pm, of course as summer moves on, the shading begins earlier. My thought is to put my hybrids there, mostly reds, some of the earlier ripening vines etc. Early morning and thru late afternoon is clear good sun exposure with no southern tree shade.
I know there lots of other variables, GDD etc. but in general, how important is the last hour or two of sunlight in the day?

Thanks for the guidance... from a complete newbie.

Cheers
 
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salcoco

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initially it sounds like it should not be a problem. all the sun you can get will help with ripening.
 

KevinL

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All day sun is best, but in backyard vineyards there is always going to be some shade especially if your neighbors have trees. My plot has the issue with trees on all sides. So while all but a few vines get good sun, there isn't any part of the day in which they don't get some kind of shade. I still get grapes that ripen relatively evenly. A little bit of sun being blocked from a single side won't be an issue.
 

BigH

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In terms of photosynthesis, you won't lose much. The late day sun is not nearly as powerful as the mid day sun pounding down directly on the leaves. However, there are some cons
  • Dew forms earlier on vines shaded in the evening, which means they will be wet longer overnight
  • They will spend more time in temperatures conducive to fungal growth
  • You won't get as much sun hitting the sides of clusters during ripening
Plan your rows so you can capture as much morning sun as possible. You will probably want to employ leaf pulling on the east side so you get some sun hitting the clusters.

H
 

Kilohertz

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Thanks everyone, much appreciated.

I am still in the planning stages, and still need to find a Canadian source of Marquette and a couple of other red hybrids, haven't decided yet, prefer potted, and prefer BC source. :h

I was out there at sun up this morning and it gets full morning and most of the daytime sun, last night the west half was shaded by 5pm, the east side of the area was in sun until about 6pm, sundown here now at 7:30pm. (I'm at 51*N Lat) The posts are the old raspberry farm area, will need to pull those and mow the grass, that will result in less shade. :h The total usable area will be about 60' N-S X 40' E-W

These pics were taken at 5PM.

Cheers

Looking NW
IMG_7024.JPG
Looking South
IMG_7022.JPG
 
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BigH

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Which direction is the grown sloping to on this site? aka the aspect of the site.
 

BigH

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Our property is on the south side of the valley, so standing on the top of the slope we are looking north
How many GDD does your site get per year? What is the percent grade of your slope? At 48 degrees N, a North facing slope at 10% grade gets about 10% less sun energy than flat ground in June, and 20% less in September.

A single wrong variable doesn't make a site a bad location for grapes, but you might be combining 3: Northern latitude, shade in for the final 3 hours of the day, and a north facing slope. It would be wise, IMO, to take your annual GDD total and subtract 20%. Plant varieties that will ripen with that reduced amount of heat. Marquette, Crimson Pearl, Edelweiss and Brianna may be good candidates. You might have a hard time ripening Verona, Petite Pearl and the Frontenacs.

If those are not high value trees, consider thinning them out to let some some sun in. Lastly, consider using Grapeman's modified GDC trellis if you go with east-west facing rows.

Good luck
H
 
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