Advice on Soil Prep for small backyard vineyard

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Jul 23, 2019
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Hi all.
I am new to the forum and brand spanking new to attempting to grow grapes for wine making. My goal is to plant about 20 vines in my back yard and make what I can from their yield. My sentimental pipedream is to be able to grow vinifera vines (graft/rootstock) taken from my late uncle’s vineyard in the Willamette Valley, Oregon, the idea being to attempt to grow variety(s) known to grow well in my area (southeastern Pennsylvania). My uncle left the vineyard to a local university to do research, and while I do have access to vines, I can only take what they can part with at any given time (usually during late winter pruning).

My plan-B, and more pragmatic approach, would be to attempt to grow hybrids that are known to do well in my neck of the woods. Either way, I am planning to do this as a phased approach with the first phase being to plant test vines (two vines each of three varieties known to grow here) and see how they do after a year, and select the variety that does the best in my little terroir. Planning to plant the test vines in spring 2020, and as such I am gearing up to prep my soil. I have had the soil tested and am looking for advice on the next steps.

I am more than willing to wait an additional year if that is what it takes to properly prepare the ground. I am a geologist by day, and as such appreciate soil primarily from a textural perspective. I am planning to conduct a perk test, and have access to coarse material to enhance drainage if necessary (soil is clayey, and derived from schist. My intent is to excavate 3 feet wide by three feet deep for the length of the rows to work the soil, enhance drainage and add necessary amendments.

The chemical amendment of soil sends me into uncharted waters. The results of my soil testing are as follows:
OM (%): 2.2
ENR (lbs/A): 68
Phosphorous (M3/ppm): 9
Potassium (ppm): 68
Magnesium (ppm): 155
Calcium (ppm): 563
Sodium (ppm): 30
pH: 5.3
Acidity (H meq/100g): 2.0
C.E.C (meq/100g): 6.4
Percent base saturation: K 2.7, Mg, 20.2, Ca 44.0, Na 2.0, H 31.2
Sulfur (ppm): 24
Zinc (ppm): 3.1
Manganese (ppm): 32
Iron (ppm): 153
Copper (ppm): 0.8
Boron (ppm) 0.3

The following is the advice I was given by the lab based on these results:
"The soil PH is 5.3 which is very low. I would suggest applying 2 tons per acre of Calcium lime and incorporate into the soil as soon as possible. In addition I would broadcast 140 units of Phosphorous and 3 lbs. or Boron per acre in a blended fertilizer. Vinifera are very sensitive to low PH and show many deficiency symptoms at this PH. It will be important to monitor plant nutrient status with petiole sampling once vines are established."

The plot in my yard is nowhere near an acre, so that was kind of amusing advice to get (I did specify it is a small backyard project, but oh well) . I can do the math to figure out the quantities based on my actual plot size.

So my questions are:

Is my pH really “very low”? It is my understanding that the optimal soil pH for most grape varieties is 5.5 to 6.5, and as such, I’m not quite sure why my pH at 5.3 is considered “very low”.

How should amendments be worked into the soil? They mention broadcasting, but not quite sure if it should also be worked deeper?

How should soil amendment be timed with respect to a target planting of test vines next spring?

Should I re-test the soil prior to planting to ensure the amendments have resulted in the target values?

One idea I was considering to enhance sun exposure to the vines is to stagger them with respect of one row to another (so that the vines won’t be side by side in a row, but rather staggered. Are there any issues with this approach?

Sorry to be so long winded, and I appreciate any advice (or be pointed in the right direction to further research). I have home brewed before, and plan to use the time between now and the time my own vines are <hopefully> productive, to make wine starting with kits and working to fresh grapes. At any rate, it has been exciting to plan this, and I hope I can implement it as best as possible.

Many Thanks, and Cheers!

What is growing in the area where you plan to plant the vines? Does the soil have healthy growth currently? I would say break the vine area into a 1000 or 2000 square foot area or areas. Then break down your acre nutrient recommendations to a 1000 k level. About the best you can do is till it in now as best as your able and then do an annual soil test. The Boron and other micro nutrients shouldn't be passed over. You can use something like Milorganite as a carrier, and blend the (20 mule team Borax) micros into the fertilizer. Then apply with a lawn broadcast spreader. Best to lightly spritz the fertilizer before you mix in the micros. Some of the micros you might be better applying monthly throughout the growing season.
No matter how you treat the soil now, you are dealing with tons and tons of material. Deficiencies might easily show up later and it could be helpful to do petiole analysis down the road and apply nutrients foliar. Say hello to agriculture, on a micro scale.
I am brand new myself although my approach is less ambitious on the time scale but I'm using some natives as test mules to get experience dealing with pest and whatnot. It is my understanding that 5.5-6.5 is a range and the tastier mountain dwelling grapes are on the high side of the range whereas the lower elevation forest/river dwelling grapes are on the lower more acidic side.

Also a difference between tolerated and preferred too. I may have to link up with you if that's ok, I have a few different native soil types I'm experimenting with.

Most recent is a high sand content mix. While it was not considered at first it seems the pest find the media unfavorable(minus the Japanese beetles).

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